EFFECTS OF WATER POLLUTION
SAN FRANCISCO BAY
by
GENE E. WILLEKE
This research was supported by grant WP-01194-01
from the Federal Water Pollution
Control Administration
Report EEP-29
October 1968
PROGRAM IN ENGINEERING-ECONOMIC PLANNING • STANFORD UNIVERSITY
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EFFECTS OF WATER POLLUTION
IN SAN FRANCISCO BAY
By
Gene E. Willeke
PROJECT ON ENGINEERING-ECONOMIC PLANNING
STANFORD UNIVERSITY
STANFORD, CALIFORNIA
Report EEP-29
October 1968
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This report was originally prepared as a
copyrighted dissertation submitted to the
Department of Civil Engineering and the Committee
on the Graduate Division of Stanford University
in partial fulfillment of the requirements for
the degree of Doctor of Philosophy.
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ACKNOWLEDGMENTS
Of the many persons who contributed in one way or another to the
research reported in this thesis, several made particular contributions
that I wish to acknowledge.
The impetus to study the interfaces between civil engineering and
the social sciences came, in large part, from my wife, Carol. She has
also been an important critic when necessary.
Professor Ray K. Linsley further encouraged this probing into the
social sciences and suggested the consideration of survey research as a
principal tool. His comments have always been helpful.
Of the several social scientists who influenced this study,
Professors William J. Paisley and Wilbur Schramm have certainly been
among the most helpful.
Mr. Aaron Levy and Miss Joie Hubbert of Field Research Corporation
had both the insight to grasp the nature of my research effort and the
professional competence to carry through the field work, with the help
of a good staff and good interviewers, in a remarkable way.
For guidance in the intricacies and details of computer program-
ming and use, I am indebted to Mr. John Arrington and Dr. Ray
Funkhouser.
Mr. James McCarty was very helpful in problem definition and in
providing background on San Francisco Bay.
Thanks are due to a friendly critic, Mr. James W. Meek, who could
often understand concepts I could not yet communicate in words.
For funding, I am grateful for the support of the Federal Water
Pollution Control Administration (Grant WP-01194-01).
iv
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For assistance in typing, I am grateful to Miss Carol Streit,
Mrs. Barbara Miner, and Mrs. Beatrice Sanders.
Finally, I am very grateful to the 914 persons whose names I do
not know but whose freely given responses are reported and analyzed in
the following pages. Their contribution has been a public service that
will perhaps recompense them for giving a portion of their time and
their thought to answer what may have appeared to be unimportant
i>
questions.
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TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS iv
LIST OF TABLES vii
LIST OF ILLUSTRATIONS x
CHAPTER
I. INTRODUCTION 1
II. VARYING PERCEPTIONS OF SAN FRANCISCO BAY 10
III. CONSEQUENCES OF PERCEIVED POLLUTION OF SAN
FRANCISCO BAY 40
IV. POLICY AND PROGRAM IMPLICATIONS 71
V. SUMMARY • 85
APPENDIX
A. SURVEY ADMINISTRATION 90
B. DATA SUMMARY 125
C. DEMOGRAPHIC VALIDITY CHECKS 144
D. STATISTICAL TECHNIQUES 147
BIBLIOGRAPHY 151
vi
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LIST OF TABLES
Table Page
II-l. Appealing and Unappealing Aspects of San Francisco
Bay 10
II-2. Typical Category Coding Examples, Appealing and
Unappealing Aspects of San Francisco Bay 11
II-3. Unappealing Aspects of Bay vs. Evaluation of Bay
Water Quality 14
II-4, Household Income vs. Unappealing Aspects of the
Bay 15
II-5. Unappealing Aspects of the Bay vs. Evaluation of
the Bay Area as a Place to Live 17
II-6. Terms Coded as Pollution 18
II-7. Information About Bay Pollution vs. Evaluation of
Bay Water Quality 22
II-8. Recent Information About Bay Pollution or Fill vs.
Evaluation of Bay Water Quality 23
II-9. Amount Heard About Bay Pollution or Fill vs.
Information About Bay Pollution 23
11-10. Amount Heard About Bay Pollution or Fill vs.
Information About Bay Pollution 24
11-11. Sex vs. Evaluation of Bay Water Quality 25
11-12. Sex vs. Participation in Recreational Activities
on the Bay 25
11-13. Predictor Set for Evaluation of Bay Water Quality . . 26
11-14. Evaluation of Bay Water Safety vs. Willingness to
Eat Fish Caught in the Bay 29
11-15. Evaluation of Bay Water Safety vs. Evaluation of
Bay Water Quality 30
11-16. Information About Bay Pollution vs. Evaluation
of Bay Water Safety 32
11-17. Recent Information About Bay Pollution or Fill vs.
Evaluation of Bay Water Safety 32
vii
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LIST OF TABLES—Continued.
Table page
11-18. Amount Heard About Bay Pollution or Fill vs.
Evaluation of Bay Water Safety 33
11-19. Harm Caused by Contact with Bay Water vs.
Evaluation of Bay Water Safety 34
11-20. Frequency of Seeing Bay vs. Attitudes Toward
the Bay 36
11-21. Summary of Recreational Use of the Bay 37
11-22. Participation in Recreational Activities on the
Bay vs. Attitudes Toward the Bay 38
1II-1. Reasons for not Engaging in Activity on San
Francisco Bay 42
III-2. Effects of Perceived Pollution on and Participation
in Recreational Activities, by Activity 44
III-3. Percent of Persons Interested in Participating
in Recreational Activity on the Bay 47
III-4. Evaluation of Bay Water Safety vs. Effects of
Perceived Pollution on Recreational
Activities 48
III-5. Willingness to Eat Fish Caught in Bay ys. Effects
of Perceived Pollution on Recreational
Activities 49
III-6. Evaluation of Bay Water Quality vs. Effects of
Perceived Pollution on Recreational
Activities 49
III-7. Information About Bay Pollution vs. Effects of
Perceived Pollution on Recreational
Activities 51
III-8. Recent Information About Bay Pollution or Fill
vs. Effects of Perceived Pollution on
Recreational Activities 51
III-9. Amount Heard About Bay Pollution or Fill vs. Effects
of Perceived Pollution on Recreational
Activities 52
viii
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LIST OF TABLES—Continued.
Table Page
111-10. Location of Recreational Activity on the Bay 53
III-ll. Sex vs. Effects of Perceived Pollution on
Recreational Activities 54
111-12. Age vs. Effects of Perceived Pollution on
Recreational Activities 55
111-13. Household Income vs. Effects of Perceived
Pollution on Recreational Activities 55
111-14. Education vs. Effects of Perceived Pollution
on Recreational Activities 56
111-15. Household Composition vs. Effects of Perceived
Pollution on Recreational Activities 56
111-16. Employment Status vs. Effects of Perceived
Pollution on Recreational Activities 57
111-17. Length of Residence in Bay Area vs. Effects
of Perceived Pollution on Recreational
Activities 57
111-18. Predictor Set for Effects of Perceived Pollution
on Recreational Activities 60
111-19. Evaluation of Bay Water Quality vs. Willingness to
Eat Fish Caught in Bay 63
111-20. Evaluation of Bay Water Safety vs. Willingness to
Eat Fish Caught in Bay 64
111-21. Amount Heard About Bay Pollution vs. Willingness
to Eat Fish Caught in Bay 65
111-22. Information About Bay Pollution vs. Willingness
to Eat Fish Caught in Bay 66
111-23. Education vs. Willingness to Eat Fish Caught
in Bay 67
IX
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LIST OF ILLUSTRATIONS
Page
Figure III-l. Schematic Diagram of Questioning
Procedure
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I. INTRODUCTION
BACKGROUND
In recent years, water pollution control has become an increasingly
important focal point of water resources management in the United
States. This has occurred for a variety of reasons, including the
decreasing quality of our water resources in key localities, the
increased desire and capacity to use these resources—particularly for
recreational purposes—and the fact that often an aroused public has
demanded cleaner water.
In meeting these demands for cleaner water, water quality control
investigators frequently are confronted with the question of what,
precisely, are the effects of polluted water on recreational activities.
The question can be further elaborated and the following list of more
specific questions is not untypical:
a. Are people being affected by polluted water at the present
time? If so, how many people are affected and in what ways?
b. What are the relationships, if any, among water quality levels
and degrees of impairment for recreational use?
c. Given a present situation of recreational use impairment by
low quality water, what changes in water quality would effect
increased recreational use of a water body?
d. What actions, other than improving water quality, could be
taken to bring about increased recreational use of a water
body?
e. Can the effects of water pollution on recreational activities
be quantified, so that these effects can be compared with
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the costs of improving water quality?
This is only a partial list, but it poses important questions that
require the attention of both the private and public sectors of society.
The quesjtions have a larger significance in that very similar questions
are being asked in other areas of engineering, including air pollution,
transportation, urban development, housing and solid waste disposal.
This list of questions provides a framework for the objectives of
the research program. The methods of study are in large part those of
the social sciences. The research effort is not, however, an attempt to
advance the social sciences; rather, it is an engineering study, an
attempt to use the social sciences—theory and method—to aid in the
solution of an important problem.
Several decades ago, health and esthetics were the primary reasons
for water quality control. Concerns about health were directed toward
drinking supplies. The concern with esthetics was framed in terms of
"common decency" (Public Health Activities Committee, pp. 75-76).
Stream and lake conditions were often vile, an evaluation with which
both conservationist and industrialist alike might have agreed, although
their judgments about what should be done, if anything, may have been
widely divergent.
Occasionally, other issues such as fish kills, the discharge of
highly toxic substances into water, and prolific algae growths have also
been targets of pollution control efforts.
Considerable progress has been made over the years in quality
control. The safety of drinking water supplies is no longer considered
a problem. To all intents and purposes, it has been solved, primarily
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by the treatment of raw water before distribution and secondarily by
the treatment of municipal and industrial wastes before discharge into
receiving waters. With exceptions, the requirements of "common decency"
have generally been met. Despite these achievements, quality control
efforts have increased, rather than decreased, and are, at present,
concerned with problems more closely related to improving the quality
of the environment. Suitability of water for recreational activities
and higher esthetic standards have taken the place of the old justifi-
cations for quality control programs. The shift to higher standards
of water quality has been accompanied by decision problems that are in
many ways more difficult than those of several decades ago (Fair,
Geyer, and Okun, 1966).
Domestic and industrial wastes receive many kinds and levels of
treatment. Considering the case of municipal sewage, at least five
kinds of treatment can be identified in current practice: 1) Primary
treatment, involving settling and/or screening, is the lowest level of
treatment. Settleable solids are removed and a portion of the biochemi-
cal oxygen demand (BOD) is removed. 2) Beyond primary treatment, the
usual step is secondary biological treatment. Secondary biological
treatment removes a much higher percentage of BOD, nearly all the
settleable solids, and a substantial percentage of pathogenic micro-
organisms. 3) Disinfection may be used after primary or secondary
biological treatment with the particular intent of destroying or
reducing the population of pathogenic micro-organisms. 4) Tertiary
treatment processes have received little use until recent years and
their use is not widespread. These processes include filtration,
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oxidation, and chemical treatment. They are used for further removal
of pathogens, BOD, nutrients, and other materials. 5) Chemical treat-
ment is sometimes used after primary treatment to effect a degree of
treatment intermediate between primary and secondary biological treat-
ment .
In cases where oxygen considerations are of most importance, the
decision to use a higher level of treatment than is presently being
given may not be difficult. Low oxygen levels in receiving waters are
accompanied by a number of undesirable conditions that both cause
economic loss and offend "common decency". If oxygen considerations are
not of great importance, it is much more difficult to decide that a
higher level of treatment than is presently being given should be
applied to domestic sewage. If challenged to identify those water uses
affected by existing levels of water quality and to indicate the
magnitude of abuse effects, it is difficult or impossible to produce
such evidence.
Recreational use of San Francisco Bay is a prime example. Recent
quality reports on San Pablo Bay, Northern and Central San Francisco
Bay show that dissolved oxygen levels are relatively high (7-9 mg/1)
and that dissolved oxygen is not considered a major problem in these
parts of the Bay (Storrs, et al., 1964). There are no defensible
bacterial standards that can be used to show that recreational use of
the Bay need be inhibited by high bacteria counts (Public Health
Activities Committee, 1964, pp. 68-69). Yet, the higher levels of
sewage treatment being asked for by regulatory authorities are those
whose major effects are to reduce BOD, bacteria counts, and a
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heterogeneous group of additional substances. Chlorination or other
disinfection practices that were initiated by the East Bay Municipal
Utility District and the City of San Francisco at its S. F. Plant in
1966 (State Policy, 1967, p. 1-8) are entirely concerned with bacterial
reduction. It may properly be asked whether the quality standards being
promulgated and considered by regulatory authorities are justified and
whether the expenditures for additional treatment facilities are likely
to be accompanied by the enhancement of the general welfare; in
particular, the enhancement of recreational activity and esthetic
enjoyment of San Francisco Bay.
It would be desirable, if possible, to express the answer to this
question in terms of monetary values that could be directly compared
with the costs of constructing treatment facilities and other quality
control measures. Because the water uses most likely to be affected
are recreational and esthetic in character, difficulty would be
expected in achieving this goal. (It is not suggested that economic
evaluation of the magnitude of these effects is impossible, although
such an evaluation was not attempted in the present investigation.)
The anticipated difficulty of measurement in monetary terms stems
in part from the fact that standards of esthetic judgment vary among
individuals. An important factor is the standard of comparison, which
might be a mental picture of another body of water—the Pacific Ocean,
Lake Tahoe, Clear Lake, etc.—or a formal set of quality standards.
In addition to varying standards of judgment, individuals have varying
perceptions of their environment. Water considered "clean" by one
individual might be considered "dirty" or "polluted" by others.
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Although judgments are important in perception, the amount of infor-
mation and the way it has been selected, organized and interpreted are
more important (Berelson and Steiner, 1964, p. 88).
OBJECTIVES
To proceed with the investigation of the ways in which water
pollution as perceived by people living in the Bay Area affects
recreational behavior and personal habits, a more specific list of
objectives was formulated in terms of the following questions:
1. What attitudes and opinions do Bay Area adults have about the
present quality of Bay water and about the effects this water
could have on a person?
2. What sources are used in acquiring information about the Bay,
what sources are credible, and what sources are considered to
have a responsibility for informing the public about the Bay?
3. How many persons refrain from participation in recreational
activities on San Francisco Bay because of their perception of
some aspect of water quality?
4. How much confidence do persons have in the ability of society
and technology to cope with Bay pollution?
5. Is pollution of San Francisco Bay an issue of importance to
the Bay Area public?
6. What are the implications for policies and programs of the
findings of this investigation?
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RESEARCH PLAN AND METHODOLOGY
Collecting information on individual perceptions and judgment
standards of San Francisco Bay requires direct contact with individuals.
To obtain this information, a survey of a representative sample of
adults was conducted in the nine Bay Area counties during September-
October, 1967.
The respondents were selected in a four-stage process. In the
first stage, the geographic study area was divided or stratified into
three parts:
a. North Bay—Marin, Solano, Napa, and Sonoma counties;
b. East Bay—Contra Costa and Alameda counties; and
c. Peninsula—San Francisco, San Mateo, and Santa Clara
counties.
In the second stage, key addresses for each of the three regions
were selected from telephone directories by a systematic random
procedure.
The third stage was conducted in the field, and consisted of the
selection of clusters of five households, including the household at
the key address, by a systematic procedure.
The final stage was the selection of a person within the household.
This determination was made in the field by the interviewer on a quota
basis. In each cluster of five households, not less than two nor more
than three, men could be included. Further details of sample selection
and research administration are given in Appendix A.
The final sample consisted of 914 respondents, with 204 cases in
the North Bay, 326 cases in the East Bay, and 384 cases on the
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Peninsula. These proportions were approximately those desired. The
North Bay and East Bay samples are larger relative to the Peninsula
sample than would be indicated by the respective populations of these
areas. Disproportionate sampling was used to ensure a sufficiently
large sample in each of the areas to make possible better interpretation
of contingency tables for each of the areas, if desired.
The sample was determined to be representative of the population
of the Bay Area on the basis of demographic comparisons with the 1960
U.S. Census. With allowances for trends since 1960, the sample has
similar distributions of ethnic groups, education, household income, and
age. Details are given in Appendix C.
The questionnaire, included in Appendix A, is the operationaliza-
tion of the research objectives. Every effort was made in its
construction to deal with possible threats to validity. The question-
naire was pretested in two stages. Question 36 was pretested alone and
the complete questionnaire was pretested on a different sample.
GENERAL NOTES
The total sample was a stratified sample. The probability of a
household being included in the sample was not proportionate to the
population of the region. Because of this fact, the tabulations in the
text often have an N other than 914. Many of the tables have an N of
763 or 765. These two figures are approximately equal to the maximum
subsample of the total sample that can be obtained while maintaining
the probability of a household being included in the sample propor-
tionate to the population of the subregion.
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The sample of 763 or 765 was divided into random halves for some
analyses, so that conclusions based on one sample could be checked on
the other. Therefore, an N of about half this number appears in some
of the analyses.
Where the text says a figure or set of figures is based on the
total sample, an N of 914 should be assumed, if it is not explicitly
mentioned.
Unless otherwise specified, an asterisk, "*", as a table entry
signified a percentage less than 0.5 percent.
Explanatory footnotes are placed at the end of the chapter in
which they appear. Literature references are at the end of the report.
All chi-square tests are tests of the hypothesis of no relationship
between the variables.
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II. VARYING PERCEPTIONS OF SAN FRANCISCO BAY
APPEALING AND UNAPPEALING ASPECTS OF THE BAY
The first insights into public attitudes toward the Bay come from
Questions 4 and 5 at the beginning of the questionnaire. These ques-
tions ask, in turn; "What are the most appealing things to you about the
San Francisco Bay itself?" and "What are the most unappealing things
about the Bay?"
Responses were categorized into six relevant groups. The cate-
gories and the percent of responses falling in each category for the
full sample are shown in Table II-l. Table II-2 gives typical examples
TABLE II-l. APPEALING AND UNAPPEALING ASPECTS OF
SAN FRANCISCO BAY.
Appealing Unappealing
Water Pollution 0% 51%
View 73 8
Water Characteristics (General) 23 10
Recreation Opportunities 13 5
Climate 9 6
Commercial Factors 5 8
Nothing in Particular 8 28
Irrelevant Responses 3 4
N = 914
10
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TABLE II-2. TYPICAL CATEGORY CODING EXAMPLES, APPEALING AND
UNAPPEALING ASPECTS OF SAN FRANCISCO BAY.
VIEW
Appealing Unappealing
Like to look at the Bay Too cluttered with buildings
Like to see the skyline Unesthetic
Lights Skyline destroys view
Ships Not good to look at
Boats Signs
Scenery Cars too close to Bay
Seagulls Tract houses
Specific spots on the Bay Signs
WATER CHARACTERISTICS (GENERAL)
Appealing Unappealing
Color of water Salt flats
Beauty of water Swamps
Variety of water Mud flats
Clean looking Water too shallow
Sparkling Too cold
Peaceful Too rough
Relaxing
Calming
Like smell
Salt water
RECREATION OPPORTUNITIES
Appealing Unappealing
Water skiing Not good for water skiing,
Fishing fishing, swimming, sailing
Boating Beaches inaccessible
Sailing Beaches unmanaged
Beaches Need more recreation areas
CLIMATE
Appealing Unappealing
Cooling effect Fog
Fog Smog
Fresh air Humidity
Temperate weather Dampness
Windy
11
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TABLE II-2—Continued
COMMERCIAL FACTORS
Appealing Unappealing
Good for shipping Port facilities antiquated
Economic privileges Industries dirty looking
Travel Shoreline too industrialized
Bridges mean fast travel Too much traffic
Harbors Freeways near Bay
Fishing industry (commercial)
NON-BAY ANSWERS
Appealing Unappealing
Golden Gate Park Don't like Bay area
Skyways Specific non-Bay features of
Freeways BaY area
Chinatown Husband jumped from Golden
Zoo Gate Bridge
WATER POLLUTION
Unappealing
Refuse
Debris
Dirty water
Garbage
Filling
Oil on water
Murky
Stagnant
Odor
Dumps
Wastes
Kills fish
Dirty beaches
12
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of responses coded in each category. These responses were not entirely
confined to the Bay itself, but included the land in the Bay area and
its cities. There can probably be no clear line of division between
public perception of the Bay and of the surrounding region.
People in the nine-county Bay area are, in general, favorably
disposed toward San Francisco Bay. They more often cite things they
like, than dislike, about the Bay, as shown in Table II-l. More than
one-fourth of the respondents found nothing in particular unappealing
about the Bay, compared with 8 percent who found nothing in particular
appealing about the Bay.
There is a diversity of reaction to the Bay. Almost as many people
dislike the climate as like it. Twenty-three percent like the charac-
teristics of the water, while 10 percent dislike them. Five percent
like the commercial aspects of the Bay; 8 percent dislike them. Almost
three-fourths of the people like the view; 8 percent dislike it.
Thirteen percent find the recreation opportunities appealing; 5 percent
do not. Such a diversity is to be expected although, a priori, one
could not have predicted the percentages.
Over half of the people cite water pollution as an unappealing
aspect of the Bay. Later in the questionnaire, 50 percent of the
respondents said they thought the Bay was polluted. They are not all
the same persons who gave a response coded as water pollution in the
former question (Table II-3). Twenty-three percent of those who
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TABLE II-3. UNAPPEALING ASPECTS OF BAY vs. EVALUATION OF
BAY WATER QUALITY.
Unappealing Aspects of Bay
Pollution All Other Total
61%
23
16
100%
397
40%
39
21
100%
366
51%
31
18
100%
763
Bay is Polluted
Don't Know, Not Sure
Bay is Not Polluted
Total
Number of Cases
N = 763, Chi-square = 34.9, 2 degrees of freedom, .001 level of
significance.
mentioned something coded as pollution in the former question did not
know for sure in the latter question whether the Bay was polluted and 16
percent said that it was not, while 40 percent of those who did not
mention pollution in the former question did believe that it was
polluted when asked about it later. This comparison indicates that the
concept of pollution probably differs somewhat in the two questions.
There is a high degree of regional uniformity in response to the
questions on likes and dislikes. The only major difference is that in
the East Bay, 16 percent of the respondents dislike some water charac-
teristic, compared with 8 percent and 7 percent in the Peninsula and
North Bay, respectively.
Annual family income was the only demographic variable signifi-
cantly related to the citing of pollution as an unappealing feature of
the Bay (Table II-4). Persons from households in the lowest income
14
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TABLE II-4. HOUSEHOLD INCOME vs. UNAPPEALING ASPECTS OF THE BAY.
Unappealing Aspects
of Bay
Pollution
All Other
Total
Number of Cases
Under
$5.000
28%
72
100%
162
$5,000-
7,499
43%
57
100%
131
$7,500-
9,999
52%
48
100%
141
$10,000-
14,999
46%
54
100%
180
Over
$14,999
48%
52
100%
88
Refused
33%
67
100%
61
Total
42%
58
100%
763
N = 763, Chi-square = 22.1, 5 degrees of freedom, .001 level of significance,
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group (less than $5,000) mentioned pollution less frequently than did
those in all higher income groups. The group that refused to give their
income was more like the lowest income group than the others, for this
question.
General satisfaction with the Bay Area is coupled with an apparent
desire to improve it. Question 36, part 11, states "The Bay Area is a
wonderful place to live and should stay just as it is." Thirty-seven
percent of the respondents agreed or strongly agreed with this item, and
forty-two percent disagreed or strongly disagreed, with twenty-one
percent undecided. This item provides less information than would be
desirable because it asks first whether the Bay Area is a wonderful
place to live (with which one might agree, despite undesirable features)
and, second, whether the Bay Area should stay just as it is (with which
one might disagree on many grounds despite liking the Area as a place
to live in comparison with other places).
The responses to the above item, considered together with Question
5 (unappealing aspects of the Bay) take on added significance. A
negative response to Question 36, part 11, probably should be inter-
preted to mean that people generally do like the Bay Area but would not
like it to stay just as it is. The nature of desired changes is not
apparent, however, 50 percent of those who mentioned pollution as an
unappealing aspect of the Bay, disagreed that the Bay Area should stay
as it is, compared with 35 percent of those mentioning other unappealing
aspects (Table II-5). This would indicate that pollution is one of the
factors about the Bay Area that people would like to have changed.
16
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TABLE II-5. UNAPPEALING ASPECTS OF THE BAY vs.. EVALUATION OF THE
BAY AREA AS A PLACE TO LIVE.
The Bay Area is a Unappealing Aspects of Bay
wonderful place to
live and should
stay lust as it is
Strongly Agree
Agree
Undecided
Disagree
Strongly Disagree
Pollution
11%
22
17
41
9
All Other
15%
27
26
28
5
Total
13%
24
21
35
7
Total 100% 100% 100%
Number of Cases 470 444 914
N = 914, Chi-square = 28.1, 4 degrees of freedom, .001 level of
significance.
PERCEPTION OF BAY WATER QUALITY
Terminology
The concept of pollution, as applied to San Francisco Bay in this
survey, has meanings that differ somewhat from question to question.
Most of the variation results from the meaning of the concept to the
respondent in the context of the questions rather than to definitions
used in the coding process. All the meanings are similar, but the
differences are sufficiently important to merit consideration in the
interpretation of survey results. If this is not done there are a few
inexplicable anomalies.
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Table II-6 gives examples of the responses to particular questions
TABLE II-6. TERMS CODED AS POLLUTION.
Unappealing Aspects of the
Bay (Question 5)
Major Recreational
Activities (Questions 7,
8, 10, 11, 13, 14, 16,
17)
Would you eat fish caught
in the Bay? (Question
18b)
Terms
refuse; debris; dirty water; garbage;
filling; oil on water; murky;
stagnant; odor; dumps; wastes; kills
fish; dirty beaches
polluted; dirty; garbage or debris
floating on water; scum; unsanitary;
makes you sick
fish unsafe; undesirable; polluted
because they've been in Bay water;
wouldn't eat if knew; fish have oily
taste; bad odor; garbage or sewage
in Bay; fish aren't clean or healthy;
would eat if assured of safety
(questionnaire is in Appendix A) that were coded as water pollution.
Unappealing aspects of the Bay (Question 5) and the group of questions
on major recreational activities (7, 8, 10, 11, 13, 14, 15, 16, and 17)
are most similar in coding. For these questions, any response concern-
ing an aspect of water quality other than temperature was coded as
pollution. Question 18b, "Would you eat fish caught in the Bay?", used
the same approach but this question was limited to fish and the
responses considered relevant from a pollution standpoint were somewhat
different as can be seen from the table.
In all other cases, the meaning of pollution must necessarily be
different, because the word is used as a stimulus to which the inter-
viewee responds. The response depends entirely upon the interviewee's
18
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conception of the term, and varies, therefore, from person to person.
The varying meanings of the term pollution necessarily imply that
a certain amount of irreducible error will be present in some of the
interpretations. An example has already been given (Table II-3). Of
those persons who cited pollution as an unappealing aspect of the Bay,
16 percent said later in the questionnaire that the Bay was not polluted
now, and 23 percent either did not know or were not sure whether the Bay
was polluted. Unless one makes the unlikely assumption that the
opinions of this many persons have changed radically in the course of
the interview, one must necessarily assume that there are differences
in meaning or perception.
Question 24, "How do you think someone could tell whether the Bay
were polluted or not?", provides information on what the respondent
considers pollution. Visual evidence or odors were mentioned by about
79 percent, and scientific analysis by 27 percent, of the respondents.
The terms used by the respondents in describing the signs of pollution
are similar to those used in the coding of the questions listed in
Table II-6: debris; garbage; dead fish, birds, and animals; oil; foam
on water; filth; odor; dirty, murky, scummy water; muddy; slimy; etc.
Quality control agencies normally characterize pollution primarily
by a formal set of chemical, biological, or physical measurements, such
as dissolved oxygen, BOD, suspended solids, nitrogen, phosphorus,
bacteria counts, etc., rather than by visual and odor criteria.
The value of a formal set of quality requirements is beyond
question as a basis for evaluating quality trends and issuing quality
control orders. Agreement on these requirements by the parties
19
-------
concerned provides a mechanism for compliance (social pressure,
supplemented by the possibility for legal action).
A disadvantage of most formal characterizations of pollution is
that they may have little relationship to pollution as perceived by the
public. Formally "clean" water may be considered "polluted" and vice
versa by the public, leaving recreational activities virtually
unbenefitted by the standards.
Evaluation of Present Condition of the Bay
Of the 50 percent of the respondents who thought the Bay was
polluted, 25 percent rated the Bay extremely polluted, 55 percent rated
it somewhat polluted, and the remainder rated it only slightly polluted.
These figures indicate the extent of the variation in perception of Bay
water quality. The variation should have an important influence on
quality control planning and implementation, particularly in obtaining
public support for quality control measures. These problems are
considered in Chapter IV.
Appraisals of Bay water quality could not readily be made from the
evaluations given by the respondents in this survey. As an assessment
of Bay quality, the scale of severity of pollution is at best ordinal,
with the three categories representing low, medium, and high quality.
It may not meet the practical requirements of an ordinal scale and
certainly does not meet formal requirements because of varying defini-
tions, a problem that could not really be solved without a uniform
standard of comparison. However, these personal evaluations are very
influential on decisions about personal use of the Bay, because it is
20
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the characterization of a condition by a person that influences his
action. It is quite immaterial whether the Bay is crystal clear,
bacteria free, and odorless, or murky, odorous, and filled with bacteria,
except as these features are influential in forming the characterization
of the Bay.
The Public Health Activities Committee of the American Society of
Civil Engineers (1963, p. 67) cites evidence that bathers do not always
perceive water to be hazardous, even in the presence of quarantine signs
and guards to enforce the quarantine. If a person believes the Bay is
extremely polluted, his activities or lack of them on the Bay are
influenced by this belief rather than by the actual state of the water
(actual state being a perception of the water through the eyes or
instruments of someone else). This would be a trivial observation if
it were not for the fact that opinions about the relative degree of
pollution of the Bay will be seen to be one of the best predictors of
whether a person's recreation activities have been affected by percep-
tion of Bay pollution.
Perception of Bay water quality is most closely related to the
information variables. It is no surprise that perception should depend
upon information. The degree of association between perception of Bay
water quality and the particular measures of information in this study
provide strong confirmation of the relationship (Table II-7). Persons
who have heard the Bay is polluted are much more likely, than are those
who have not, to believe that the Bay is polluted. The table shows
that information is not the only factor shaping perceptions of Bay
quality. One-third of the persons who had heard the Bay is polluted
21
-------
TABLE II-7. INFORMATION ABOUT BAY POLLUTION vs. EVALUATION OF BAY
WATER QUALITY.
Heard Bay
is Polluted
66%
24
10
100%
502
Don ' t Know ,
Not Sure
32%
50
18
100%
34
Never Heard
Bay is Polluted
20%
43
37
100%
227
Total
50%
32
18
100%
763
Bay is Polluted
Don't Know,
Not Sure
Bay is Not
Polluted
Total
Number of Cases
N = 763, Chi-square = 157.4, 4 degrees of freedom, .001 level of
significance.
either were not sure or did not think it was polluted now.
The relationship between evaluation of Bay water quality and
Question 27a, "Have you heard anything recently about Bay pollution or
Bay fill?", is not as strong but is still significant (Table II-8).
Persons who have recently heard something about Bay pollution or Bay
fill are more likely to believe the Bay is polluted.
There is a strong association between the evaluation of Bay water
quality and Question 29, "How much have you heard about Bay pollution
or Bay fill?" (Table II-9). The more a person has heard about Bay
pollution or Bay fill, the more likely he is to say the Bay is polluted.
The internal consistency between the questions "Have you ever heard
that San Francisco Bay is polluted?" and "How much have you heard about
22
-------
TABLE II-8. RECENT INFORMATION ABOUT BAY POLLUTION OR FILL vs.
EVALUATION OF BAY WATER QUALITY.
Heard
Recently
60%
26
14
Haven't Heard
Recently
38%
38
24
Total
50%
32
18
Bay is Polluted
Don't Know, Not Sure
Bay is Not Polluted
Total 100% 100% 100%
Number of Cases 462 301 763
N = 763, Chi-square = 35.6, 2 degrees of freedom, .001 level of
significance.
TABLE II-9. AMOUNT HEARD ABOUT BAY POLLUTION OR FILL vs.. EVALUATION
OF BAY WATER QUALITY.
Amount Heard
Great
Deal Somewl
Bay is Polluted
Don't Know, Not Sure
Bay is Not Polluted
Total 100% 100% 100% 100% 100%
Number of Cases 132 238 198 195 763
N = 763, Chi-square = 151.7, 6 degrees of freedom, .001 level of
significance.
23
Great
Deal
84%
11
5
Somewhat
65%
24
11
Not
Much
41%
33
25
Hardly
Any
22%
50
28
Total
50%
32
18
-------
Bay pollution or Bay fill?" is shown in Table 11-10. If Question 26a,
TABLE 11-10.
AMOUNT HEARD ABOUT BAY POLLUTION OR FILL vs.
INFORMATION ABOUT BAY POLLUTION.
Heard Bay is
Polluted
Don't Know,
Not Sure
Never Heard Bay
is Polluted
Total
Number of Cases 132
Amount Heard
Great
Deal
90%
2
8
100%
132
Somewhat
84%
1
15
100%
238
Not
Much
65%
6
29
100%
198
Hardly
Any
28%
9
63
100%
195
Total
66%
4
30
100%
763
N = 763, Chi-square = 194.6, 6 degrees of freedom, .001 level of
significance.
"Do you think the Bay is polluted?", is dichotomized into "Yes" and
"Not yes", either of these information variables used as predictors
predicts correctly in over 70 percent of the cases. Thus, the value of
these two questions as predictors is apparent. If the trichotomy is
maintained in Question 26a, each predicts almost 60 percent of the
cases correctly.
Of the demographic variables, only sex is significantly associated
with a belief that the Bay is polluted (Table 11-11). Males more
frequently say that the Bay is polluted than do females, but the real
difference is that a higher percentage of females do not know or are
24
-------
TABLE 11-11. SEX vs. EVALUATION OF BAY WATER QUALITY.
Male
56%
24
20
Female
47%
37
16
Total
50%
32
18
Bay is Polluted
Don't Know, Not Sure
Bay is Not Polluted
Total 100% 100% 100%
Number of Cases 382 381 763
N = 763, Chi-square = 16.4, 2 degrees of freedom, .001 level
of significance.
sure. Because males have higher rates of participation in recreational
activities on the Bay (Table 11-12), it might be suggested that the
issue is more relevant to males than to females.
TABLE 11-12. SEX vs. PARTICIPATION IN RECREATIONAL
ACTIVITIES ON THE BAY.
Male Female Total
Boating or Sailing on Bay 41% 24% 32%
Swimming on Bay 17 9 13
Water Skiing on Bay 312
Fishing on Bay 34% 12% 22%
Number of Cases 177 197 374
25
-------
A multivariate discriminant analysis was performed to determine
the combination of predictors that best discriminate between persons
who believe the Bay is polluted and those who do not. Demographic,
information, credibility, and Bay recreational use variables were used
in the predictor set (Table 11-13). Two of the information variables—
TABLE 11-13. PREDICTOR SET FOR EVALUATION OF BAY WATER QUALITY.
A. Demographic Variables
Age
Education
Income
Sex
Ethnic Group
Length of residence in Bay Area
B. Information Variables
How much have you heard about Bay pollution or Bay fill?
Have you ever heard the Bay is polluted?
Have you heard anything recently about Bay pollution or fill?
Have you received enough information about Bay pollution or fill?
C. Contact with Bay
Frequency of seeing Bay
Have you ever gone boating or sailing on the Bay?
Have you ever gone swimming on the Bay?
Have you ever gone water skiing on the Bay?
Have you ever gone fishing on the Bay?
D. Credibility Variables
Credibility of federal government
Credibility of state government
Credibility of local government
Credibility of newspaper editorials or articles
Credibility of television documentaries
Credibility of private conservation organizations
Credibility of scientific experts
Credibility of close friends
26
-------
"Have you ever heard the Bay is polluted?" and "How much have you heard
about Bay pollution or Bay fill?"—discriminate between the two groups
as well as the full predictor set. It is interesting to note that the
discriminant functions developed for one random half of the 765-case
subsample actually correctly assigned a higher proportion of cases for
the other random half though the differences are not great. The overall
accuracy of group assignment was 71 percent. For persons who thought
the Bay was polluted, the average accuracy was 80 percent and for
persons who did not think the Bay was polluted, 62 percent.
The nature of the discriminant function is such that persons who
have heard the Bay is polluted and who have heard more about Bay pollu-
tion or Bay fill are more likely to think the Bay is polluted. The
discriminant analysis and contingency table analysis reach identical
conclusions. The additional information provided by the discriminant
analysis is that the addition of other variables from this predictor
set does not noticeably improve the relationship. This would be hard
to demonstrate with contingency tables alone, because of the large
number of three-way cross tabulations required to exhaust the combina-
tions of variables taken three at a time that are logically related to
the criterion of discrimination (the belief that the Bay is or is not
polluted) and that can be shown to be significantly related to the
criterion in bivariate tabulations.
Respondents who said the Bay is polluted were asked a series of
questions to elaborate on this response, including Question 26c, "What
do you think causes San Francisco Bay to be polluted?" The average
number of causes mentioned per respondent was 2.1. City sewers,
27
-------
industrial wastes and chemicals, and garbage dumping or Bay fill were
each mentioned by 50-60 percent of the respondents.
Perhaps the most important aspect of this response pattern is that
no single source of wastes received an overwhelming majority of the
responses. Although a certain amount of scapegoating may be present in
these responses, the majority of the respondents seem to have a percep-
tion of the causes of Bay pollution close to the reality of a complex
system with multiple causes.
Apprehensions About The Bay
Some persons have apprehensions about the Bay which will be seen
later to have a strong influence on the degree to which participation
in recreational activities on the Bay is affected. Two questions were
used to measure these apprehensions, Question 20a, "At the present
time, do you feel that contact with Bay water could be harmful to a
person in any way?" and Question 18a, "Would you eat fish caught in the
Bay?" The latter question will be discussed further in Chapter III,
but certain aspects of the relationship between these and other varia-
bles will be considered at this point.
Twenty-seven percent of the respondents thought contact with Bay
water could be harmful to a person. Of these persons, 95 percent
thought the harm would take the form of some medical ailment, external
(such as skin irritations) or internal (such as intestinal disorders or
a generalized, non-specific sickness). A third of the persons who
thought the Bay could be harmful thought that it could be extremely
harmful, 40 percent thought it could be somewhat harmful, and the
28
-------
remaining one-fourth either thought it could be only slightly harmful
or did not make a judgment.
In answer to Question 18a, 12 percent of the respondents gave a
qualified response and 16 percent said they would not eat fish caught
in the Bay. About 60 percent of the persons who gave either a qualified
or negative response gave a reason coded as related to water pollution
for not eating fish caught in the Bay.
The relationship between these two attitude questions that express
apprehension about the Bay is shown in Table 11-14. Persons who believe
TABLE 11-14. EVALUATION OF BAY WATER SAFETY vs. WILLINGNESS TO
EAT FISH CAUGHT IN THE BAY.
Would Eat Fish
Caught in Bay
Would Eat Fish
Under Certain
Conditions
Would Not Eat Fish
Caught in Bay
Total
Contact
Could Be
Harmful
59%
15
26
100%
Don't Know,
Not Sure
66%
17
17
100%
Contact
Could Not
Be Harmful
81%
12
100%
Total
72%
12
16
100%
Number of Cases
205
209
349
763
N - 763, Chi-square = 36.4, 4 degrees of freedom, .001 level of
significance.
contact with Bay water could be harmful to a person are more likely not
29
-------
to eat fish caught in the Bay than are those who believe contact could
not be harmful. Conversely, (though the figures are not shown in Table
11-14) persons who would not eat fish caught in the Bay are more likely
to believe that contact with Bay water could be harmful to a person.
The direction of association cannot be specified.
Opinions about the degree of threat posed by the Bay are strongly
associated with perception of the present condition of the Bay (Table
11-15). Of those persons who think contact with Bay water could be
TABLE 11-15. EVALUATION OF BAY WATER SAFETY vs. EVALUATION
OF BAY WATER QUALITY.
Bay is Polluted
Don't Know, Not Sure
Bay is Not Polluted
Total
Number of Cases
Contact
Could Be
Harmful
86%
10
4
Don't Know,
Not Sure
43%
45
12
Contact
Could Not
Be Harmful
36%
34
30
Total
50%
32
18
100%
205
100%
209
100%
349
N = 763, Chi-square = 161.0, 4 degrees of freedom, .001 level of
significance.
100%
763
harmful to a person, twice as many also think the Bay is polluted as is
the case among persons who do not believe contact with Bay water could
be harmful.
Questions 18a, 20a, and 26a, (Would you eat fish..., Could contact
30
-------
be harmful..., Is Bay polluted...) seem to form a cluster of attitudes
and perceptions, highly interrelated, and all associated in the same
direction with measures of the consequences of perceived Bay pollution,
as will be discussed in Chapter III. These questions are, in turn, all
strongly associated with the information variables.
As Question 18a will be discussed more thoroughly in Chapter III,
only the relationship of Question 20a with other variables will be
explored here. There were no strong associations between Question 20a
and the demographic variables. A few relationships were statistically
significant—sex, ethnic group, and education—but of no practical
significance, maximum variations being a few percentage points.
The importance of information sources is underscored by the
relationships shown in Tables 11-16, 11-17, and 11-18. In all these
tables, it can be seen that increasing amounts of information about the
Bay are associated with greater likelihood of believing that contact
with Bay water could be harmful to a person. Although the content of
messages is not studied in this survey, it is clear that a negative
tone is prevalent in the information that has been communicated about
the Bay. In the light of published reports about the Bay in recent
years, the content of the communicated messages is probably unneces-
sarily negative, because the Bay seems generally of good quality. This
matter is discussed further in Chapter IV.
One would expect that persons who have become ill or suffered
harmful effects from contact with Bay water would be more likely to
believe that contact with Bay water could be harmful to a person. The
relationship is shown in Table 11-19. There is indeed a significant
31
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TABLE 11-16. INFORMATION ABOUT BAY POLLUTION vs. EVALUATION
OF BAY WATER SAFETY.
Heard Bay Don't Know,
is Polluted Not Sure
Contact Could Not
Be Harmful
38
47
Have Not
Heard Bay is
Polluted Total
Contact Could Be
Harmful
Don ' t Know ,
Not Sure
36%
26
12%
41
10%
27
27%
27
63
46
Total
100%
100%
100%
100%
Number of Cases
502
34
227
763
N = 763, Chi-square = 66.4, 4 degrees of freedom, .001 level of
significance.
TABLE 11-17. RECENT INFORMATION ABOUT BAY POLLUTION OR FILL vs..
EVALUATION OF BAY WATER SAFETY.
Heard
Recently
Haven't Heard
Recently
Contact Could Be Harmful
Don't Know, Not Sure
Contact Could Not Be
Harmful
35%
26
39
15%
30
56
Total
27%
27
46
Total
100%
100%
100%
Number of Cases
462
301
763
N = 763, Chi-square = 39.6, 2 degrees of freedom, .001 level of
significance.
32
-------
TABLE 11-18. AMOUNT HEARD ABOUT BAY POLLUTION OR FILL
vs. EVALUATION OF BAY WATER SAFETY.
Amount Heard
Contact Could Be
Harmful
Don't Know, Not
Sure
Contact Could Not
Be Harmful
Total
Number of Cases
Great
Deal
50%
21
29
100%
132
Somewhat
35%
24
41
100%
238
Not
Much
18%
34
48
100%
198
Hardly
Any
10%
29
61
100%
195
Total
27%
27
46
100%
763
N = 763, Chi-square = 85.1, 6 degrees of freedom, .001 level of
significance.
33
-------
TABLE 11-19. HARM CAUSED BY CONTACT WITH BAY WATER vs.
EVALUATION OF BAY WATER SAFETY.
Have Become Don't Have Suffered
111 or Suffered Know, No Harmful
Harmful Effects
69%
0
31
100%
13
Not Sure
14%
64
21
100%
14
Effects
27%
27
46
100%
887
Total
27%
28
45
100%
914
Contact Could
Be Harmful
Don't Know,
Not Sure
Contact Could
Not Be Harmful
Total
Number of Cases
N * 914, Chi-square = 22.5, 4 degrees of freedom, .001 level of
significance.
relationship, though it is not as striking as might be expected.
Moreover, one-third of those who have suffered harmful effects do not
believe that contact with Bay water could be harmful to a person.
Though the number of cases involved, using the full 914-case sample, is
small, even here one can see the variability of response to a stimulus,
the stimuli being on the one hand suffering harmful effects from Bay
water and, on the other, the questions posed in the survey.
EXTENT OF CONTACT WITH THE BAY
Two measures of the extent of actual contact with the Bay are
included in the questionnaire. The first, Question 3, is entirely of
34
-------
visual contact, "How often do you see or look at any part of either San
Francisco Bay or San Pablo Bay?" The second measure is of participation
in recreational activities on the Bay, either in the past year or at
some time prior to last year.
The distribution of responses to Question 3 is distinctly bimodal,
with modal points at the extremes:
Frequency Percent viewing Bay
Every day 24%
Two or three times a week 10
About once a week 10
Two-three times a month 12
About once a month 13
Less often than once a month 32
The median frequency of seeing the Bay is two-three times a month.
Relationships between frequency of seeing the Bay and the variables
measuring attitudes toward the Bay are shown in Table 11-20. Persons
who see the Bay more often are more likely to believe the Bay is pol-
luted.
A summary of participation in recreation activities on the Bay is
given in Table 11-21. Less than half the respondents have never
participated in any recreation activity on the Bay while almost half
have participated in one of the four major activities.
Relationships between participation in recreational activities on
the Bay and attitudes toward the Bay are shown in Table 11-22. In this
table, participation means participation at some time, not necessarily
last year. Some of these relationships are significantly different from
zero as measured by the chi-square test, but few are large enough to be
of any practical consequence. In all cases, persons who have at some
35
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TABLE 11-20. FREQUENCY OF SEEING BAY vs. ATTITUDE TOWARD THE BAY.
Bay is polluted
Contact with Bay
water could be
harmful to a person
Would not eat fish
caught in Bay
Number of cases
Every 2-3 Times
Day a Week
57% 58%
32 27
13% 8%
Once a
Week
59%
28
23%
2-3 Times
a Month
52%
26
17%
Once a
Month
43%
22
13%
Less Often
Than Once
a Month
46%
25
22%
Total
51%
27
17%
175
74
71
96
98
249
763
Chi-square - 23.0, 10 degrees of freedom, .02 level of significance.
"Relationship is not significant.
-------
TABLE 11-21. SUMMARY OF RECREATIONAL USE OF THE BAY.
Percent Participating
Major Activities
None
One
Two
Three
Four
Boating or Sailing
Swimming
Water Skiing
Fishing
Other Recreation Activitie
At Any Time
53%
28
14
4
*
34
13
2
22
s 32
Last Year
79%
16
5
*
0
13
4
*
10
__
Major Activities plus other Activities 60
N = 914
37
-------
TABLE 11-22. PARTICIPATION IN RECREATIONAL ACTIVITIES ON THE BAY vs.
ATTITUDES TOWARD THE BAY.
Water Other
Boating Swimming Skiing Fishing Activitieg Total
Bay is Polluted 58% 59% 50% 63% 50% 50%
Contact With Bay
Water Could Be
Harmful to a
w Person 31 27 28 34 26 27
oo
Would Not Eat
Fish Caught in
Bay 12% 13% 11% 14% 12% 16%
Number of Cases 308 116 18 202 295 914
-------
time participated in a recreation activity on the Bay are somewhat less
likely to say that they would not eat fish caught in the Bay. Only the
differences for boating, fishing, and other recreational activities are
statistically significant. In all cases, persons who have used the Bay
at some time are at least as likely as the population as a whole to say
that the Bay is polluted and that contact with Bay water could be harm-
ful to a person. The most striking observation is that people who have
fished on the Bay at some time are much more likely to say that the Bay
is polluted than are those who have not. It may be concluded that, in
general, contact with the Bay does not cause a person to consider the
Bay unpolluted.
39
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III. CONSEQUENCES OF PERCEIVED POLLUTION
RECREATIONAL ACTIVITIES
Questioning Procedure
Five questions formed the operationalization of the process of
determining whether a person had been affected by pollution. These
five questions were embedded in a longer series of questions that is
shown schematically in Figure III-l and completely in the questionnaire
reproduced in Appendix A. Each person was given an opportunity to give
reasons for his non-participation or reduced level of participation in
each of four recreational activities on the Bay (boating or sailing,
swimming, water skiing, and fishing). Responses to the questions were
recorded verbatim and included a wide variety of reasons. Consistent
with the goals of the survey, they were grouped into three categories:
a. Water pollution
b. Other water characteristics
c. All other
By receding of the questions, other questions such as access to the Bay
or the more specific issue of water temperature could have been studied
but were not considered germane to the consideration of the effects of
pollution alone. Multiple responses to these questions were accepted
and coded. It is therefore possible in every case to ascertain whether
pollution, e.g., was cited in conjunction with some other factor.
Overall Effects of Pollution
Table III-l summarizes the responses given to the questions dealing
with the four major recreational activities. Shown in this table are:
40
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FIGURE III-l. SCHEMATIC DIAGRAM OF QUESTIONING PROCEDURE.
Have you gone fishing anywhere in the past year?
Yes
How many days
did you fish?
How many days did you fish on
L. Berryessa Clear Lake Bay N. Calif. Other
1 or more
Where do you usually
fish in Bay?
Are days fished in Bay
more than half of total
days fished last year?
Yes
I
END
No
Zero
i
Why didn't you
fish in Bay
last year?
END
Why didn't you
fish in Bay
more often?
No
Have you ever fished
in Bay?
Yes
Why didn't you
fish in Bay
last year?
END
Yes
Why havent't
you been fishing
in Bay?
END
No
Would you be
interested in
fishing in the
Bay?
No
Why aren't you
interested in
fishing in the
Bay?
END
END
-------
TABLE III-l. REASONS FOR NOT ENGAGING IN ACTIVITY ON SAN FRANCISCO BAY.
(All figures are in percent of total respondents)
Swimming
Water
Skiing
Fishing
Boating or
Sailing
Single plus
multiple
responses
1.
2.
3.
Water pollution
Other water
characteristics
All other
reasons
20.2%
36.0
56.3
5.4%
14.1
85.0
2.4%
6.4
83.4
1.6%
7.5
78.7
Single responses only
4.
5.
6.
Water pollution
Other water
characteristics
All other
reasons
10.6
21.0
45.6
2.9
8.5
80.0
1.7
3.9
80.8
.9
5.0
76.4
Multiple responses only
7.
8.
Water pollution
and other water
characteristics
Water pollution
and all other
reasons
6.6
2.3
1.5
1.0
.3
.4
.4
.2
9. Water pollution,
other water
characteristics,
and all other
reasons .7 0 0 .1
10. Ratio of water
pollution alone to
total water
pollution 52% 54% 71% 56%
42
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a) the total proportions of persons citing reasons for non-participation
or reduced participation (alone and in conjunction with other reasons);
b) the proportions of persons who cited reasons in only one of the three
categories; and c) the ratio of the proportion of persons citing only
water pollution to the total proportion of persons citing water pollu-
tion.
Line 1 shows that swimming is the activity most affected by Bay
pollution, with 20 percent of the respondents having cited it. Water
skiing is next, with 5 percent, one-fourth of the proportion whose
swimming activities have been affected. Fishing and boating or sailing
are last with about 2 percent each.
Lines 4 and 10 show that the majority of the persons citing pollu-
tion give it as the only reason.
Lines 2 and 3 show that in all cases, both other water character-
istics and all other reasons outrank pollution as reasons for non-
participation or reduced participation in the activity on the Bay.
Many of these factors other than pollution are of potential interest
in the management of the Bay, but, apart from the fact that certain
proportions of the respondents mentioned one or more of these other
factors in conjunction with water pollution, they are not of particular
relevance to the present investigation.
The percentages of persons who said that pollution has affected
their recreational activities are compared in Table III-2 with the
percentages of persons who participated in the activity last year,
anywhere and on the Bay. This table shows that the number of persons
for whom water pollution is a reason for not swimming in the Bay is
43
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TABLE III-2. EFFECTS OF PERCEIVED POLLUTION ON AND PARTICIPATION IN
RECREATIONAL ACTIVITIES, BY ACTIVITY.
Water Boating or
Swimming Skiing Fishing Sailing
Total Affected by
Pollution 20% 5% 2% 2%
Affected by Pollution
(Only reason) 11 3 2 1
Participated in
Activity on Bay
last year 4 * 10 13
Participated in
Activity Anywhere
last year 30 7 28 27
Ever Participated in
Activity on Bay 12% 2% 22% 33%
N = 763
two-thirds as large as the total number of persons who went swimming
somewhere besides swimming pools last year. The number of persons who
cited pollution as the only reason is almost as large as the number of
persons who have ever been swimming in the Bay, and is five times as
large as the number who went swimming in the Bay last year. These
figures do not include teenagers and children under 12 years of age.
(Younger persons were not included in the survey because of the desire
to study a wide range of attitude and information factors.)
If the conservative assumption is made that the proportion of
persons under 18 years of age whose swimming activity is affected by
pollution is at least as great as that of the population as a whole,
44
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approximately 1,000,000 persons in the Bay Area are affected. This
estimate is considered conservative because a higher proportion of
younger persons swim (Outdoor Recreation Resources Review Commission,
1962, p. 214) and because the present survey shows that as age
decreases, the proportion of persons affected increases.
These figures do not imply that if perceived pollution were
removed as a reason for not swimming in the Bay, 20 percent of the
population would then swim in the Bay. It is conceivable that those
persons who cited other reasons in addition to pollution would refrain
from swimming in the Bay because of these reasons. It is also con-
ceivable that persons who have expressed perceived pollution as the
only reason might, after attempting to swim in the Bay, find other
reasons such as access and water temperature to be sufficient deterrents
to swimming in the Bay.
Two issues are involved. One is the effect of perceived pollution
on recreational activities. The other is the possible increase of
recreational use of the Bay. It must be concluded by definition that
perceived pollution is affecting all the persons who cited it as a
reason for not swimming in the Bay (20 percent of the respondents). If,
at some time in the future, as a result of a combination of circum-
stances, perceived pollution were not considered a deterrent to swimming
in the Bay, the effect of perceived pollution would be reduced to zero.
Potential increase in swimming use of San Francisco Bay, however,
cannot be accurately estimated from this survey and from assumptions
about future water quality conditions in the Bay. It can only be said
that if perceived pollution is eliminated as a basis for not swimming in
45
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the Bay, there is virtually certain to be an increased tendency for
swimming in the Bay. Other deterrents, such as access and temperature,
may be so strong that the actual increase in swimming could be small or
zero.
It should be appreciated that the operational definition of a
pollution effect is a particular kind of measure. It is not an
exhaustive definition. E.g., if increased swimming use of the Bay were
a desired program goal, further analysis of the detailed structure of
responses, particularly those in which pollution and other reasons were
given, would be required.
Referring again to Table III-2, it is seen that the percentage of
persons citing pollution as a reason for not water skiing in the Bay is
high relative to the percentage of persons who water skiied anywhere
last year and who have ever water skiied on the Bay. It is just as true
for water skiing as for swimming that the elimination of perceived
pollution as a reason for non-participation does not imply an increase
of water skiing in the Bay equal to the proportion of persons giving
pollution as a reason.
Fishing and boating or sailing are affected to a relatively small
degree, compared with the proportion of persons who: a) used the Bay
last year for the activities; or b) have participated in the activity
somewhere last year; or c) have participated in the activity on the Bay
at some time.
An additional set of figures is useful in evaluating potential
demand for recreational activities on the Bay. Persons who did not
participate in the activity anywhere during the past year and who have
46
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never used the Bay for the activity were asked whether they would be
interested in using the Bay for the activity. These responses overlap
those used for determining whether a person had been affected by
perceived pollution (Table III-3). These figures indicate that the
TABLE III-3. PERCENT OF PERSONS INTERESTED IN PARTICIPATING IN
RECREATIONAL ACTIVITY ON THE BAY.
Boating 18%
Swimming 5
Water Skiing 12
Fishing 12%
N = 914
potential demand is relatively large for each of the activities,
except swimming. The figure for swimming is misleadingly low because
over 10 percent of the respondents were not interested in swimming in
the Bay because of water pollution.
In order to make effective use of the information that certain
proportions of the population are refraining from participation in an
activity on the Bay because of pollution, it is desirable to know more
about the relationship of this response to other responses. It is of
importance to know whether these persons differ from the rest of the
population and, if so, how and to what degree.
The variables of most importance in determining whether a person's
recreational activities have or have not been affected by Bay pollution
47
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are the attitude and information variables. One of the most important
is Question 20a, "Do you feel that contact with Bay water could be
harmful to a person in any way?" (Table III-4). The proportions of
TABLE III-4. EVALUATION OF BAY WATER SAFETY vs. EFFECTS OF PERCEIVED
POLLUTION ON RECREATIONAL ACTIVITIES.
Contact Could Contact Could
Activity Affected be Harmful Not Be Harmful
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
to a Person
42%
40
14
4
4%
and Don't Know
17%
15
3
2
1%
Total
24%
20
5
2
2%
Number of Cases 205 558 763
persons whose recreational activities have been affected by perceived
Bay pollution are in all cases much higher—by a factor of 2-4—among
persons who believe that contact with Bay water could be harmful to a
person.
A similar pattern is seen for the relationship between whether a
person's recreational activities have been affected and whether he
would be willing to eat fish caught in the Bay (Table III-5) . In all
cases, the proportion of persons whose recreational activities have
been affected by pollution is at least 60 percent higher among persons
who would not eat fish caught in the Bay than among persons who would
48
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TABLE III-5. WILLINGNESS TO EAT FISH CAUGHT IN BAY vs. EFFECTS OF
PERCEIVED POLLUTION ON RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Would Not
Eat Fish
35%
30
9
9
4%
Would Eat
Fish
19%
18
4
*
1%
Total
24%
20
5
2
2%
Number of Cases 222 541 763
be willing to eat fish caught in the Bay.
Evaluation of the present condition of the Bay is likewise very
distinctly related to whether a person's recreational activities have
been affected (Table III-6). In all cases, the proportions of persons
TABLE III-6. EVALUATION OF BAY WATER QUALITY vs. EFFECTS OF PERCEIVED
POLLUTION ON RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Bay is
Polluted
33%
30
10
5
3%
Don't Know,
Not Sure
14%
13
2
1
1%
Bay is Not
Polluted
14%
14
1
0
1%
Total
24%
20
5
2
2%
Number of Cases 390 235 138 763
49
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whose recreational activities have been affected by pollution is more
than twice as great among persons who think the Bay is polluted as
among persons who do not think the Bay is polluted or are not sure.
These three indicators of perception of Bay water quality are good,
but not perfect, predictors and the reasons are apparent. A person
could think the Bay is polluted or believe contact with Bay water could
be harmful to a person or not wish to eat fish caught in the Bay and
yet have no interest in any of the recreational activities for reasons
other than perceived Bay pollution.
Because perception is closely associated with information and
because effects of pollution on recreational activities depend,
apparently, on perception, one would expect to find a relationship
between the information measures and the proportions of persons whose
recreational activities have been affected by perceived Bay pollution.
Tables III-7 through III-9 show the relationship for three of the
information measures. Increasing information is associated with
greater proportions of persons being affected.
The interpretation of the significance of the information measures
could proceed in two ways. It could be said that as persons come to
"know the facts", they avoid the Bay. It could also be said that the
information content of messages used by persons to form opinions about
the Bay is negative and that this is why people have a negative opinion
of the Bay. Up to this point, it is irrelevant whether a negative
information content is appropriate for description of Bay water quality.
In terms of formal quality characteristics, those for which
numerical evaluations can be made by scientific analysis, there is
50
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TABLE III-7. INFORMATION ABOUT BAY POLLUTION vs.. EFFECTS OF PERCEIVED
POLLUTION ON RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Heard
Bay is
Polluted
29%
26
8
4
2%
Don't Know,
Not Sure
6%
6
0
0
0%
Have Not
Heard Bay is
Polluted
15%
14
2
0
2%
Total
24%
20
5
2
2%
Number of Cases 502 34 227 763
TABLE III-8. RECENT INFORMATION ABOUT BAY POLLUTION OR FILL vs. EFFECTS
OF PERCEIVED POLLUTION ON RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Heard
Recently
30%
26
8
3
2%
Haven't Heard
Recently
15%
15
3
2
1%
Total
24%
20
5
2
2%
Number of Cases 462 301 763
51
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TABLE III-9. AMOUNT HEARD ABOUT BAY POLLUTION OR FILL vs. EFFECTS OF
PERCEIVED POLLUTION POLLUTION ON RECREATIONAL
ACTIVITIES.
Amount Heard
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Great
Deal
38%
35
11
7
4%
Somewhat
32%
29
8
4
2%
Not Very
Much
22%
20
3
1
2%
Hardly
Any
7%
6
3
1
1%
Total
24%
20
5
2
2%
Number of Cases
132
238
198
195
763
little in the published record that could be interpreted as justifying
a negative information content (and it should be appreciated that such
a statement must necessarily be somwhat subjective and depend upon a
particular point of view). The State of California cites some quality
problems (State Policy, 1967, pp. 1-6 through 1-8), but the worst
problems are indicated as being in the southern portion of the Bay and
in San Pablo Bay. The Bay is used most for recreational activities in
the zones of best quality, between San Mateo Bridge and the Richmond-San
Rafael Bridge (Table 111-10). It is quite likely that, based on formal
characterization of Bay water quality, the information content of mes-
sages about the Bay is unduly negative.
As pointed out in the previous chapter, formal characterizations
of water quality do not normally deal adequately with the factors that
52
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TABLE 111-10. LOCATION OF RECREATIONAL ACTIVITY ON THE BAY.
Zone
Boating or Water
Sailing Swimming Skiing Fishing
A (South of San Mateo
Bridge)
B (San Mateo Bridge
to Bay Bridge)
C (Bay Bridge to
Richmond-San
Rafael Bridge)
D (North of Richmond-
San Rafael Bridge)
Total
Number of Cases
10%
20
42
28
100%
120
11%
31
44
14
100%
27
**%
**
N.A.
8%
25
41
26
100%
88
N = 914
**The one person who had water skiied on the Bay did not say where he
had skiied.
are of most concern to the public at large. It is therefore quite
possible that even if chemical and bacteriological analyses of the Bay
revealed water of high quality, the factors noticed by the public might
be very much in evidence. The State does in fact mention (State
Policy, 1967, p. 1-10) that oily wastes are discharged into the Bay,
though the extent of the discharge and the water affected by it are not
detailed.
The relationships between several demographic characteristics and
53
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the proportions of persons who reduce or refrain from participation in
one or more recreational activities because of perceived pollution of
San Francisco Bay are shown in Tables III-ll through 111-17. The
TABLE III-ll. SEX vs.. EFFECTS ON PERCEIVED POLLUTION ON
RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Male
27%
25
6
4
2%
Female
21%
18
6
1
1%
Total
24%
20
5
2
2%
Number of Cases 382 381 763
54
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TABLE 111-12. AGE vs.. EFFECTS OF PERCEIVED POLLUTION ON RECREATIONAL
ACTIVITIES.
Activity
Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Number of Cases
Under
25
31%
28
10
4
2%
89
TABLE 111-13. HOUSEHOLD
25-34 35-44 45-54 55-64
30% 26% 27% 19%
27 24 24 16
13 5 4 5
2136
5% 2% 1% 1%
149 168 142 85
INCOME vs. EFFECTS OF PERCEIVED
65 or
older Total
11% 24%
10 20
0 5
2 2
0% 2%
130 763
POLLUTION ON
RECREATIONAL ACTIVITIES.
Activity
Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or
Sailing
Number of
Cases
Under
$5000
15%
12
3
3
1%
162
$5000- $7500- $10000 Over
7499 9999 14999 14999
20% 26% 34% 28%
19 24 31 26
5 10 7 6
3423
2% 4% 2% 1%
131 141 180 88
Refused Total
15% 24%
13 20
3 5
0 2
0% 2%
61 763
55
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TABLE 111-14. EDUCATION vs. EFFECTS OF PERCEIVED POLLUTION ON
RECREATIONAL ACTIVITIES.
High
Activity Less Than
Affected High School
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
16%
14
4
2
1%
School
Graduate
23%
21
5
3
2%
Some
College
27%
24
8
4
4%
College
Graduate
34%
32
8
2
1%
Total
24%
20
5
2
2%
Number of Cases 204 239 186 134 763
TABLE 111-15. HOUSEHOLD COMPOSITION vs. EFFECTS OF PERCEIVED
POLLUTION ON RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Children
Under 18
28%
25
7
3
3%
No Children
Under 18
20%
19
4
3
1%
Total
24%
20
5
2
2%
Number of Cases
404 359 763
56
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TABLE 111-16. EMPLOYMENT STATUS vs. EFFECTS OF PERCEIVED POLLUTION ON
RECREATIONAL ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Fishing
Boating or Sailing
Employed
Full Time
27%
25
8
2
2%
Employed
Part Time
12%
12
0
0
0%
Unemployed
17%
14
2
4
1%
Total
24%
20
5
2
2%
Number of Cases
530
33
200
763
TABLE 111-17. LENGTH OF RESIDENCE IN BAY AREA vs. EFFECTS
OF PERCEIVED POLLUTION ON RECREATIONAL
ACTIVITIES.
Activity Affected
Any Activity
Swimming
Water Skiing
Boating or Sailing
Less than
1 Year
3%
3
0
0%
1-2.9
Years
18%
16
8
2%
3-4.9
Years
24%
22
8
4%
5-9.9
Years
21%
21
4
1%
10 or More
Years
26%
23
6
2%
Total
24%
20
5
2%
Number of Cases
34
49
50
68
562
763
57
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effects of perceived pollution are greater for men than for women, and
are consistently greater for young persons than older persons. Increas-
ing proportions of persons modify their swimming activities because of
perceived pollution as income increases, up to the $10,000-$14,999 per
year group, above which there is a decline. The decrease begins at a
lower level for water skiing, fishing, and boating or sailing. The more
education a person has, the more likely it is that he modifies his
swimming activities in the Bay because of perceived pollution. For the
other activities, the group most affected is the group which has had
some college, business, or technical school training, but has not
graduated from college. Persons from households with children are more
likely to modify their recreational activities than are persons from
households without children under 18 years of age. Persons employed
full time are more likely to be affected than are persons who are
employed part time or are unemployed, for all activities but fishing,
for which unemployed persons are affected more than persons employed
full time.
To more nearly complete the description of the things that
differentiate between persons whose recreational activities on the Bay
have been affected by perception of Bay pollution from the population
as a whole, more than one variable must be used. Demographic, infor-
mation, and attitude variables interact in a complex manner and the
relationships can neither be conveniently explored nor displayed in
bivariate tabulations. A multivariate technique, discriminant analysis,
was used to consider simultaneously the joint effects of several vari-
ables in classifying a subject into one of two groups—persons whose
58
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recreational activities on the Bay have been affected by perceived
pollution and those whose activities have not been affected.
In discriminant analysis, a linear function of variables in the
predictor set is calculated. In the procedure used for analysis in
this investigation, a function is computed for each of the groups
(Dixon, 1967, pp. 214a-214u). A subject is assigned to the group for
which his function score is highest. For example, in the two group
case, if his score for Group A is 5 and for Group B is 1, he would be
••signed to Group A. There are other decision rules that can be used
for case assignment. If one wished to be more sure of classifying
subjects of one group correctly, such a decision rule can be formulated,
at the cost of incorrectly classifying more cases of the other group.
The discriminant analysis was based on the predictor set listed in
2
Table 111-18. Five of the predictors—"How much have you heard about
Bay pollution or fill?", "How polluted do you think the Bay is?",
Educational background of respondent, "Would you eat fish caught in the
Bay?", and "Are there teenagers or children under 12 in the household?"
—give almost as high a degree of discrimination as does the full set.
The overall accuracy of assignment for the random half used in develop-
ing the functions was 71 percent as compared with 73 percent for the
full predictor set. For the other random half, the accuracy was 70
percent as compared with 72 percent for the full predictor set.
For the random half of the 765-case subsample that was used to
develop the discriminant functions, 72 percent of the affected group
Explanatory notes at end of chapter.
59
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TABLE 111-18. PREDICTOR SET FOR EFFECTS OF PERCEIVED POLLUTION ON
RECREATIONAL ACTIVITIES.
1. Age—Under 25; 25-34; 35-44; 45-54; 55-64; 65 or older
2. Sex—Male; female
3. Ethnic Group—Non-white; white
4. Education—Less than high school; some high school, not completed,
no answer; completed high school; some college, business, or
technical school; college graduate; post college graduate work
5. Teenagers or children under 12 in household—No, Yes
6. Time spent on outdoor recreation activities during a typical week—
No answer, none; less than 1 hour; 1 hour-1.9 hours; 2 hours-3.9
hours; 4 hours-5.9 hours; 6 hours-7.9 hours; 8 hours-9.9 hours;
10 hours-14.9 hours; 15 hours or more
7. Would you eat fish caught in San Francisco Bay?—Yes; qualified;
no
8. How much have you heard about Bay pollution or Bay fill?—Great
deal; somewhat; not very much; hardly any
9. Have you ever heard the Bay is polluted?—No, yes
10. Do you think the Bay is polluted now?—No, yes
11. Could contact with Bay water be harmful to a person?—Yes; don't
know, not sure; no
12. Frequency of seeing Bay—Every day; 2-3 times a week; about once
a week; 2-3 times a month; about once a month; less often than
once a month, no answer
13. Have you ever attended meetings where Bay pollution or fill was
discussed?—No, yes
14. How polluted do you think the Bay is?—extremely polluted; somewhat
polluted; only slightly polluted; not polluted
15. What features do you dislike about the Bay?—All others, water
pollution.
60
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and 71 percent of the unaffected group were correctly assigned. For the
other random half, 64 percent of the affected group and 70 percent of
the unaffected group were correctly assigned.
The functional relationship of these predictors to group membership
was such that a person who had heard less about Bay pollution or fill,
who thought the Bay was more polluted, who had more education, who
wouldn't eat fish caught in the Bay and who had teenagers or children
in his household was more likely to say that he had refrained from or
reduced his participation in some recreational activity in the Bay
because of water pollution. The probabilistic nature of this statement
is important because these conditions are neither necessary nor suffi-
cient. They indicate only that a person with these characteristics has
a higher probability of being affected by pollution than do persons
without them. Unmeasured are social pressures on the person to be
interested in outdoor, water-oriented recreation, the person's cultural
history and values, and the nature of his other commitments. If
information were available on these other factors, a higher degree of
predictive accuracy would be expected. It is doubtful that acquisition
of this information would be desirable. It would constitute a severe
invasion of privacy for the respondent and would be hard to use in
planning. Direct acquisition of data on the effects desired seems
preferable. This subject will be discussed further in Chapter IV.
WILLINGNESS TO EAT FISH CAUGHT IN BAY
Question 18a asks, "Would you eat fish which were caught in the
Bay? This question has been discussed before as an aspect of percep-
61
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tion of Bay pollution and as a predictor in the case of effects on
recreational activities. The question is useful for these purposes but
it has a larger importance in that it is a measure of another effect of
perceived pollution of the Bay. Sixteen percent of the respondents
felt strongly enough about the undesirability of eating fish caught in
the Bay that they said they would not eat them. An additional 12
percent gave a qualified response; they would eat fish caught in the Bay
if they could be assured of their safety or they would eat only certain
species. Because safety of the fish or unpalatability of the fish is
the matter of most concern to those who were unwilling to eat fish
caught in the Bay and because these conditions are thought by the
respondents to be dependent on the condition of Bay water, this seems
clearly an effect of perceived polluted water on the residents of the
Bay Area.
Perceptual factors are most closely associated with responses to
this question (Tables 111-19 and 111-20). Persons who believe the Bay
is not polluted are twice as likely to eat fish caught in the Bay as
persons who believe the Bay is polluted or who don't know. Persons who
believe contact with Bay water could not be harmful to a person are
more likely to eat fish caught in the Bay than are persons who do
believe contact could be harmful or are not sure.
Information measures are not as good predictors of whether a
person is unwilling to eat fish caught in the Bay as are the perception
questions mentioned above (Tables 111-21 and 111-22). The more a
person has heard about Bay pollution or Bay fill, the less likely he
is to eat fish caught in the Bay. However, it is not sufficient merely
62
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TABLE 111-19. EVALUATION OF BAY WATER QUALITY vs. WILLINGNESS TO EAT
FISH CAUGHT IN BAY.
Bay is Don't Know, Bay is Not
Polluted Not Sure Polluted Total
Would Not Eat Fish
Caught in Bay 23% 11% 12% 16%
Would Eat Fish Under
Certain Conditions 12 16 4 12
Would Eat Fish
Caught in Bay 65 73 84 72
Total 100% 100% 100% 100%
Number of Cases 390 235 138 763
N - 763, Chi-square = 31.5, 4 degrees of freedom, .001 level of
significance.
63
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TABLE 111-20. EVALUATION OF BAY WATER SAFETY vs.. WILLINGNESS TO EAT
FISH CAUGHT IN BAY.
Would Not Eat Fish
Caught in Bay
Would Eat Fish Under
Certain Conditions
Would Eat Fish
Caught in Bay
Total
Number of Cases
Could be
Harmful to
a Person
26%
15
59
100%
205
Don ' t Know ,
Not Sure
17%
17
66
100%
209
Could Not
be Harmful
to a Person
12%
7
81
100%
349
Total
16%
12
72
100%
763
N = 763, Chi-square = 36.4, 4 degrees of freedom, .001 level of
significance.
64
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TABLE 111-21. AMOUNT HEARD ABOUT BAY POLLUTION vs. WILLINGNESS TO EAT
FISH CAUGHT IN BAY.
Would Not Eat Fish
Caught in Bay
Would Eat Fish Under
Certain Conditions
Would Eat Fish
Caught in Bay
Total
Number of Cases
Great Not Hardly
Deal Somewhat Much Any Total
N » 763, Chi-square = 13.8, 6 degrees of freedom, .05 level of
significance.
23%
7
70
100%
132
19%
15
66
100%
238
13%
14
74
100%
198
15%
10
75
100%
195
16%
12
72
100%
763
65
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TABLE 111-22. INFORMATION ABOUT BAY POLLUTION vs.. WILLINGNESS TO EAT
FISH CAUGHT IN BAY.
Would Not Eat Fish
Caught in Bay
Would Eat Fish Under
Certain Conditions
Would Eat Fish
Caught in Bay
Total
Number of Cases
Heard Bay
is Polluted
19%
12
69
100%
502
Don't Know,
Not Sure
29%
9
62
100%
34
Have Not
Heard Bay
is Polluted
12%
12
76
100%
227
Total
16%
12
72
100%
763
N = 763, Chi-square = 8.6, 4 degrees of freedom, .10 level of
significance.
66
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to have heard the Bay is polluted. Persons who have heard the Bay is
polluted are not much less likely to eat fish caught in the Bay than
are persons who haven't heard the Bay is polluted. Persons who have
heard the Bay is polluted are more likely to eat fish caught in the Bay
than are those who don't know whether they have heard the Bay is
polluted.
Education is significantly related to whether a person would be
willing to eat fish caught in the Bay. The relationship is shown in
Table 111-23. This table shows a definite trend; as education level
decreases, the proportion of persons unwilling to eat fish caught in
the Bay increases.
TABLE 111-23. EDUCATION vs. WILLINGNESS TO EAT FISH CAUGHT IN BAY.
Less than High Some College
_ High School School College Graduate Total
Would Not Eat Fish
Caught in Bay
Would Eat Fish Under
Certain Conditions
Would Eat Fish
Caught in Bay
Total
Number of Cases
N • 763, Chi-square » 18.2, 6 degrees of freedom, .01 level of
significance.
67
23%
10
67
100%
204
17%
10
73
100%
239
17%
17
66
100%
186
8%
11
81
100%
134
16%
12
72
100%
763
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PHYSICAL HARM
In the total sample, N = 914, 1.4 percent of the respondents said
that they had personally become ill or suffered harmful effects from
Bay water. An additional 1 percent didn't know or were not sure.
There was some regional variation. On the Peninsula, 2.9 percent had
suffered harmful effects, while the proportions were 2.5 percent in
the East Bay and 1.5 percent in the North Bay.
The most significant aspect of this information is that the number
of persons whose health was actually affected by Bay water is such a
small fraction of the persons who thought that Bay water could be
harmful to a person—5 percent of those who thought that it could and
3 percent of those who either thought it could or weren't sure.
Persons who said they had become ill or suffered harmful effects
from contact with Bay water were not significantly different from the
population as a whole, in attitudes, demographic characteristics,
degree of contact with the Bay in major recreational activities, or
amount of information heard about the Bay.
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EXPLANATORY NOTES
1
In a survey of this sort, many of the variables are highly inter-
correlated. Demographic variables are intercorrelated with each other,
information variables are intercorrelated with each other and with
perception variables, and the perception variables are intercorrelated
with each other. In most cases, there is no logical basis for demon-
strating the absolute primacy of one variable over another in a
predictor set. Thus, it is possible for several combinations of
predictors to have roughly equal predictive power. The functional
relationships presented should not be considered the only possible set
of relationships.
2
It is frequently stated that one should not use a multivariate
technique unless one has a logical basis for including variables in the
predictor set. The survey analyst finds some but little guidance in
such an admonition. Even by following it rigorously, he may be left
with a number of predictors that are logically related to the dependent
variable and for which the direction of the relationship can be estab-
lished a priori. E.g., one would expect recreational activity for
water skiing and swimming to decline with age; men would be expected to
fish more than women; higher income persons would be expected to boat
or sail more than lower income persons; persons who think the Bay is
polluted would be expected to be more likely to curtail recreational
activities in the Bay than persons who did not; etc. In such a circum-
stance, the features of stepwise discriminant analysis are very
appealing, because at each step, the variable added to or removed from
the predictor set is the variable that makes the largest contribution
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to discrimination at this point.
Cooley and Cohnes have expressed a reservation about stepwise
regression techniques that seems equally applicable to stepwise
discriminant techniques, particularly for the two-group case for which
discriminant analysis and regression analysis are identical. Their
concern is that, since only the criterion or dependent variable is
treated as subject to errors, "... any effort to generalize from
sample to population is open to serious danger of capitalization on
chance" (1962, p. 35).
As a partial check on this danger, a 765-case subsample (proba-
bility proportionate to size of subregion) was divided into random
halves. The discriminant analysis was performed on one half and checked
on the other.
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IV. POLICY AND PROGRAM IMPLICATIONS
In preceding chapters, it has been shown that many people are not
participating in certain recreational activities in San Francisco Bay
because they believe it to be polluted and undesirable for use. The
activities most affected are swimming (20 percent of the adult popula-
tion of the Bay Area) and water skiing (5 percent of the adult popula-
tion) . Boating and fishing are affected very little (less than 2
percent each). The characteristics of the Bay objected to most often
are odors and visual evidences of "pollution." The visual evidences
are such things as oil, debris, foam, etc. In addition to their own
evaluations of the Bay, perceptions of and attitudes toward the Bay
are shown to be primarily related to what and how much has been heard
about the Bay.
In this chapter, implications of these and other findings for
policies and programs will be considered. Although both legislative
and administrative implications will be discussed, the discussion is
primarily concerned with implications for administrative agencies.
The number of persons who modify their recreational use of the Bay
because they believe it to be polluted may appropriately be considered
in the justification of public pollution control programs (to the
extent that public programs could reduce the extent of this recreational
use curtailment). New programs may be justified to deal with those
aspects of pollution that are of most concern to the public. For
example, the concern about visible material on the surface of the Bay
suggests the use of a corps of workers to continuously patrol and clean
up areas of beach or water surfaces, at least through recreation
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seasons. It also suggests surveillance activities on a routine basis
to identify sources of substances that are discharged into the Bay and
to take immediate, on-the-spot action to eliminate such discharges.
Such surveillance would be in accordance with State policies, though
implementation of the policy has not taken this form and clean-up work
has apparently been the responsibility of the Army Corps of Engineers
(State Policy, 1967).
The expressed demand for greater recreational use of the Bay
suggests the need to develop, in the short run, more recreational areas
and to "sell the Bay". Popular conception (Gilliam, 1957) and public
reports (Bay Conservation and Development Commission, 1968, p. 9) have
taken the position that use of the Bay for swimming and water skiing is
severely restricted by its temperature. While this does indeed seem to
be the case for many people, a large group of persons mention pollution
as a primary reason for not swimming or water skiing on the Bay.
Indeed, over half' of the persons who cited pollution as a reason for
non-participation gave it as the only reason. These responses cannot
be taken as conclusive proof that if pollution were removed as a reason
for non-participation, these persons would then use the Bay for swimming
and water skiing. It is an indicator that must be tested to be
verified.
The removal of perceived pollution as a cause for non-participation
requires the removal of barriers to participation. These barriers
include the factors that cause persons to consider the Bay polluted,
those that are observable with the unaided, untrained eye and nose as
well as those that can only be detected by careful scientific analysis.
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Other barriers include information a person has about the Bay and the
attitudes he has developed about the Bay over the years.
Removal or reduction of pollution sources historically has been
virtually the sole focus of quality control agencies. The provision of
sewage treatment facilities, policing of discharges into the Bay,
garbage dumping, filling, etc. are examples of such measures. Attitude
and information barriers have received little attention. If anything,
quality control agencies have erected attitude barriers, taking the
form: "Fight for Clean Water". It is not proposed that this orienta-
tion be dropped if it is relevant to the particular case at hand, but
it is exceedingly detrimental if it is not relevant. In the case of
San Francisco and San Pablo Bays, it applies to some portions of the
Bay and not to others. Because it doesn't apply as well to those
portions of the Bay most used for recreational activities—San Mateo
Bridge to Richmond-San Rafael Bridge—typifying the whole Bay as
polluted is detrimental to recreational use of these portions of the
Bay. If it were the case that the public could only conceive of the
Bay as a single entity that was either polluted or unpolluted, perhaps
a posture that the Bay is polluted is justified in order to gain support
for cleaning up those portions of the Bay that are polluted. However,
there is no evidence that the public has such a limited conception of
the Bay nor that it has such a limited capacity for discrimination.
These comments suggest that a more aggressive effort be made by
public agencies to portray the condition of the Bay, as it is, in
sufficient detail to correct misconceptions of the condition of the
Bay and to encourage recreational use of the Bay.
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A public information program of this sort could take several forms.
Of particular value would be a brochure on the Bay that included verbal
descriptions of various portions of the Bay and maps, such as the fish-
ing maps distributed by the California Department of Fish and Game
(Department of Fish and Game, 1965), that locate points of access,
beaches, launching ramps for water-skiing boats, and give graphic
portrayals of water conditions in addition to the verbal descriptions.
In such an information program, safety is an issue central to the
use of the Bay for body contact sports that must be faced. Bacteriolog-
ical standards have been set by health agencies for body contact sports
by the State of California that are similar to those used in other
states (State Policy, 1967). The Public Health Activities Committee of
the American Society of Civil Engineers (1963), in a review of standards
like these, concluded that they have no basis in epidemiology. The
relationship between bacteriological quality and safety for public use
has not been established. Should these standards then be used in the
evaluation of the suitability of water for swimming and water skiing?
This question obviously involves value questions and ethical decisions.
It may be argued that public agencies have a responsibility to protect
the public by establishing and enforcing standards even in the absence
of evidence that would support the guidelines. It may also be argued
that if the facts are not given to the public, an enforcement policy is
basically dishonest.
The proper role of a quality control or health agency in this
situation would seem to be that of collecting information, conducting
research, disseminating information, and allowing the public to take
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some risk now being assumed by the health agencies. The dissemination
of information might then include statements about the validity of the
standards currently being used for beach closing. Bacterial counts
could continue to be reported, if desired, thus allowing an individual
to base his actions on the old standards if he wished, though logical
consistency would dictate their omission until such time, if ever, as
they were found to be useful.
Turbidity and floating material are of primary concern to
immediate perception of water quality by potential participants in body
contact sports. These aspects of Bay water quality vary considerably,
depending upon wind conditions, inflow of water to the Bay system, and
discharges of pollutants (including accidental discharges) into the Bay.
Because these aspects of water quality do vary so widely, long-term
conditions seem of little use in making a decision to use or not use
the Bay for a recreational activity. To provide up-to-date informa-
tion, it is suggested that frequent, perhaps daily, reports of at least
turbidity and floating material be disseminated by public agencies
during at least the seasons of heavy recreational use, in much the same
manner as weather reports are disseminated by the U.S. Weather Bureau.
Intially, these reports would be general and qualitative. Quantita-
tive indexes of pullution, if and when they are developed for the Bay,
would be useful. (Air pollution reports by the news media, e.g., quote
the concentrations of substances together with limits at which eye
irritation is considered likely to take place.) Because personal
decisions are partially based on qualitative evidence (much of it
probably hearsay evidence at that) such as appearance and odor, the
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use of qualitative data presents no problems, assuming that satisfactory
observers can be obtained. The use of qualitative data may well
represent an improvement in the measurement of water quality because of
the inferior role to which qualitative data is relegated in evaluating
the condition of a water body by quality control agencies.
In addition to the effect of information programs on recreational
activities, an effect could be expected on that portion of the popula-
tion which at present would not eat fish caught in the Bay because the
fish are considered unsafe. If the fish actually are unsafe, everyone
should abstain from eating them. However, there seems to be little
basis for judging that fish caught in the Bay are unsafe for consumption.
(Taste is a factor that, of course, lies beyond the scope of this
statement because it is such an individual matter. A safe fish might
not necessarily taste good.) This subject would properly be dealt with
in both the brochures and in the daily reports.
A discussion by Gross (1966, pp. 166-167) is germane to the subject
of quality measurement of Bay water. Gross makes a comment about the
accuracy of data that seems strikingly appropriate to the present
discussion. Following a consideration of Morgenstern's treatise on
"The Accuracy of Economic Observations" (1963, pp. 242-282) in which
Morgenstern pleas for more accurate data, and, more important, an
estimate of the error associated with reported data, Gross says:
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"Yet, as against the dangers flowing from errors in
economic statistics, I must also point out, as no
less dangerous, the bias resulting from accurate
economic statistics. Greater accuracy may easily
bring with it greater irrelevance. For example, the
most accurate part of a company's balance sheet is its
statement of cash on hand. To focus on this alone
would be a ridiculous way of analyzing a company's
financial position. The balance sheet, as a whole,
does not reflect the assets that the company enjoys in
the form of its clients' good will and the support of
its cooperating organizations. These 'intangible'
factors, however, cannot be dealt with as quantita-
tively as the estimated value of inventories and
receivables. Hence, they tend to be ignored by
executives who are hypnotized by the quantitative data
in the balance sheet. (To repeat what has been said
before, the fact that a variable can be quantified—
by present techniques—may be illusory or deceptive.)"
The preceding discussion brings up the subject of quality standards
in relation to recreational activities. For purposes of enforcement, it
is desirable, perhaps imperative, to have a standard of comparison, a
basis for saying that certain actions are required for quality control.
If there were complete agreement between polluter and agency, standards
would not be required, but agreement is not universal, to say the least.
On the other hand, the evidence collected in this study would
indicate that there may be little relationship between formal character-
izations of quality levels and recreational use of a water body, because
perception of quality is the determining factor in recreational use of
a water body, and perception of quality may be greatly at variance with
formal characterization of the quality of that water body.
Even if data collection programs such as described in preceding
paragraphs were instituted, the information linkage between data
collection agency and user is a modifying factor. The information
programs described above might completely surmount this difficulty but
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they remain to be tested. However, such extensive data collection and
information programs are not in existence at the present time. The
value of standards for recreational waters is in doubt for these
reasons, and would be even more in doubt if recreational standards
were the results of a national or regional policy that was not respon-
sive to the local situation. The current state of the art is such that
quality standards for recreational waters must necessarily be kept
flexible to adapt to differing perceptions and standards of judgment
and to new findings that can be incorporated into the standards.
All the programs and policies described above are short-term,
innovative, and flexible. If they do not work, they can be discarded;
if they do work, they can be expanded and continually modified. To
determine the effectiveness of these programs on the behavior of the
public, a method of measurement must be devised. At least two
alternatives may be used either separately or, preferably, together.
At a low cost, questions can be added to regular public opinion polls
conducted in California by several organizations that could be used to
evaluate changes in public use of the Bay and public attitudes toward
the Bay, as programs were instituted or modified. Actual recreational
use of the Bay can be measured by standard counting techniques either
for total use or for selected samples. Both are low-budget methods
that provide direct information for evaluating the success or failure
of programs.
Recreational activities likely do not constitute the total effects
of perceived pollution on people, though the effects on these activi-
ties are most easily measured. At least two categories of effects are
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suggested. The first category consists of those effects that are
recognized by a person but not associated with perceived pollution.
Only if perceived pollution were not present could the cause be
identified. Another environmental problem provides a more clear
example of this type of effect. High background noise may be "tuned
out" by a person and he is not conscious that the noise is affecting
his irritability or nervousness. However, once the sound stops or
when the person moves into a different environment in which the noise
is not present, he is aware that the noise was really bothering him.
In the second category are those cases in which a person can
identify the cause but cannot verbalize the effects. These two issues
were given only minor consideration in this study, via the question
"What are the most unappealing things about the Bay?" The response of
water pollution was given by a majority of the people, much more than
for all recreational activities combined. However, the degree to which
pollution affects the life of the person is not measured or investigated
any further. This would constitute a desirable extension of the present
study and the results could be as useful.
There are other facts revealed by this survey that are relevant to
public policy. The fact that only half the people believe the Bay is
polluted now and that 18 percent believe that it definitely is not, has
important implications for financing quality control facilities and
programs. Bond issues that require two-thirds majorities would seem to
be in trouble from the beginning. Of course, there is no implication
that they will automatically fail, because information campaigns that
"sell" the program can influence many votes. Also, some persons
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automatically vote for bond issues just as others automatically vote
against them. Survey research could have an important role, in
identifying the issues, the nature of the support and the opposition,
and the probability of success, so that public agencies could more
adequately answer the questions people have about the desirability of
the bond issue. There is no substitute for the survey that has yet
been developed. Neither the findings of a public hearing nor the
conclusions of a politician with "his ear to the ground", though each
has a definite, important place in the process, are generalizable to
the voting public, except by chance.
The fact that such a substantial portion of the public knows
little about the Bay raises a serious question about the advisability
of requiring two-thirds majorities for the passage of bond issues.
This is a value question that must be decided in the political arena
and not in the conduct of an investigation such as this. It is an issue
of great importance and the information provided by this survey is
certainly relevant to the decision.
The series of questions about private conservation organizations
is both interesting and of practical consequence. The conservation
organizations appear to be vocalizing the deeply felt attitudes and
values of the public at large, as indicated by the facts that:
a) The conservation organizations without exception are
interested in cleaner water and campaign for it;
b) 71 percent of the respondents in this survey said they
care a great deal about whether the Bay is polluted,
with an additional 19 percent caring "somewhat";
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c) Only 7.6 percent of the respondents did not agree with
the item: "Our streams and lakes should be clean whether
or not we use them". Half of these were either
undecided or did not answer the item;
d) 30 percent of the respondents felt strongly enough about
the subject to say that they would be willing to donate
one day a month in the summer to help clean up beaches
(whether such a large turnout would actually be
experienced is, of course, another question, but the
degree of emotional responses to this item indicates
the depth of feeling about this environmental problem).
On the other hand, with few exceptions, persons interviewed
neither belonged to nor supported these organizations. Sixteen percent
of the respondents thought the Save San Francisco Bay Association had
taken a public position on the Bay, and 8 percent thought the Sierra
Club had taken a public position. Thus, the degree of public awareness
of their activities is such that not even a majority of the population
have an opinion on whether the organizations have taken a position on
a local issue that they consider of great importance.
The issues of credibility and public confidence are raised by the
questions "Do you think that San Francisco Bay can be cleaned up?" and
"Do you think San Francisco Bay will be cleaned up?" Only 15 percent
of those answering did not give an affirmative response to the first
question and the negative responses emphasized technical limitations
and political factors. However, half of those answering the second
question gave negative responses. Political factors, social factors,
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cost, and intransigent industries were cited as the principal reasons.
These responses indicate a major discrepancy between the possible and
the probable with the blame for the discrepancy being laid not on
technology but upon our social and political institutions.
On the other hand, the credibility of public agencies and news
media was uniformly high. Only the opinions of close friends were
considered not credible by a majority of the respondents (yet, much of
the information about Bay pollution seems to come from friends).
The news media and public agencies are seen as having the primary
responsibility for disseminating information to the public about the
Bay» and almost 60 percent of the respondents would like to have more
information about the Bay.
It is fairly common to make projections of such things as per
capita demand for recreation on the basis of demographic factors. The
evidence accumulated in this survey indicates that such procedure may
at times be poor, because the amount of variance explained in the
dependent variable by demographic factors is low. If this is actually
the case, the policy implication would seem to be that, before invest-
ing heavily in such things as economic base studies to be used in
secondary analysis, planners would be well advised to consider the use
of direct measurement of those variables that will actually be used in
planning. The Outdoor Recreation Resources Review Commission study
(1962) made a major contribution in showing the extent to which this
could be done on a nationwide scale for recreation demand. The present
study shows that much can be done in an even more nebulous area,
effects of water pollution on people. The costs of direct measurement
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may well be lower than for indirect measurement and secondary analysis.
If the increased accuracy associated with direct measurement is also
taken into account, the advantages are even greater.
In any case where large data collection programs are planned, it
seems desirable, if not imperative, to establish relationships among
predictors and dependent variables before a full-scale data collection
program is undertaken. If relationships cannot be established, there
is serious doubt that the data should be collected.
In doing secondary analysis, one is often forced to use composites
and averages, rather than multivariate arrays for individuals. Because
concomitant variation is so great among variables, the limitations of
secondary inferential analysis are great. Also, attitude variables
seem to be more important determinants of behavior than demographic and
personal characteristics.
Gross's statement (1966), quoted above, is directly relevant to the
use of quantitative data in public works planning. The most accurate
data available about people are U.S. Census data: numbers, age distri-
bution, sex distribution, etc. These data are valuable for many
purposes. However, their unrestrained and unexamined use in public
works planning may be quite as useless as using the estimate of cash on
hand as the primary basis for corporate operations. This is not to say
that measurement is worthless; quite the contrary, the usefulness of a
concept is greatly enhanced if it can be measured. What should be
emphasized is that it should not be simply assumed that unqualified
information should not be used. First, an attempt should be made to
quantify the information. If this cannot be done, then information
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should be used in its unquantified form. The history of survey research
shows that many kinds of data can be quantified. One almost wishes to
say that if the question can be formulated, a measurement can be
obtained. Such a statement is too broad, but in the realm of practical
planning problems is probably not far from the truth. Survey research
is not, of course, limited to the sampling of human populations though
it has been widely used in such instances. It is equally applicable
to the measurement of economic data, soil properties, hydrologic and
geologic data, etc.
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V. SUMMARY
A sample survey was conducted during September-October, 1967, in
the nine-county San Francisco Bay Area to determine what effect
perceived pollution of San Francisco Bay has on use of the Bay for major
recreational activities and on attitudes toward the Bay. A representa-
tive cross-section of 914 adults were personally interviewed in their
homes.
About half of the respondents, without prompting, cited water
pollution as an unappealing feature of the Bay. Persons with annual
household incomes of less than $5,000 before taxes (20 percent of the
sample respondents) and persons who refused to give their incomes (9
percent of the respondents) cited water pollution as an unappealing
feature less frequently than did persons from household with incomes
higher than $5,000 per year.
Half the respondents considered the Bay polluted at the time of the
survey while 32 percent didn't know or weren't sure and 18 percent did
not consider the Bay polluted. These opinions were strongly influenced
by the information a person had received about the Bay. In general,
the more a person has heard about Bay pollution or fill, the more
likely he is to consider the Bay polluted. Men were more likely to
have an opinion on the subject and were more likely to consider the Bay
polluted than were women. This presumably depends upon relevance of
the issue to recreational habits because men participate much more than
women in recreational activities on the Bay.
Many people have apprehensions about the potential harm that could
be caused by contact with Bay water (27 percent of the respondents) or
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by eating fish caught in the Bay (16-28 percent of the respondents).
These apprehensions reflect attitudes that are strongly associated with
modification of recreational use of the Bay. Persons who believe
contact with Bay water could be harmful to a person or who would not eat
fish caught in the Bay are much more likely to say that they do not
participate in some recreational activity on the because they find some
property of the water or its appearance undesirable or esthetically
unappealing.
About 24 percent of the respondents gave pollution as a reason for
not engaging in one or more activities on the Bay. About 20 percent
said that they refrain from swimming in the Bay because of pollution.
The comparable figure for water skiing is about 5 percent; for fishing,
2 percent; and for boating or sailing, about 2 percent. These
responses may properly be considered adverse effects of perceived Bay
pollution on the population of the Bay Area.
Men are more frequently affected by perceived pollution of the Bay
than are women. The likelihood of being affected declines with age and
increases with rising income, up to the $15,000 per year level above
which it declines. Persons from households that have children under 18
years of age are more likely to be affected than others. Persons
employed full time are more likely to be affected than others for all
activities except fishing. In the latter case, unemployed persons are
more likely to be affected than are others. For all activities except
swimming, the likelihood of being affected by perceived pollution
increases with increasing education up to the level of some college,
business, or technical school. For swimming, the likelihood of being
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affected increases with increasing education through the level of
college graduate.
Slightly over one percent of the respondents said that they had
become ill or suffered other harmful effects from contact with Bay
water. The characteristics of those persons did not differ signifi-
cantly from those of the population as a whole.
The implications for policies and programs of the above findings
may be summarized as follows:
1. The effects of perceived pollution on the recreational
activities of Bay Area adults and, by inference, to younger
persons, may appropriately be considered in the justification
of public quality control programs for the Bay, to the extent
that such programs could reduce the extent of the effects.
2. More attention should be given to contaminants that can be
observed by use of the untrained, unaided senses, both in
formal characterization of Bay water quality and in specific
quality control program activities (such as continuous
removal of visible debris and oil).
3. A greatly expanded program of public information about the
Bay seems in order. Such a program should be factual and
complete without attempting to portray it as either more or
less polluted than it is. Due regard should be given to
areal and temporal quality variation. Long-term as well as
daily public reports are in order.
4. There is probably at most a weak, insensitive relationship
between water quality as measured by conventional analytical
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techniques and recreational use of a water body. The
content of transferred information and attitudes toward
the water body are much more important factors. The
effect of changes in information content could be easily
measured by using appropriate questioning in regular public
opinion polls before and after information campaigns.
5. The low level of information (about one-third of the
respondents say they have never heard the Bay is polluted)
and the lack of consensus about Bay water quality (about
one-half either don't know or say the Bay is not polluted)
suggest that bond issue elections for quality control works
are probably conducted in a climate of ignorance. It is
clear that public agencies should inform the public about
the condition of the Bay and about the programs proposed to
control its quality. This function is a service to the
public at the same time that it is in the interest of the
agency if the agency desires public acceptance of programs
to improve or maintain the quality of water in San Francisco
Bay.
6. Survey research is shown to be a valuable means of enabling
communication from the body politic to public agencies and
legislative bodies on subjects that are of some concern to
many people but not of enough importance to these persons
to cause massive indignation and demonstration of concern.
7. Private conservation organizations, though their activities
are little known among the general public, seem to be
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voicing the widespread feelings of the general public.
8. Government agencies, scientific experts, and news media
are generally considered credible sources of information
about the Bay.
9. For many planning activities, it seems advisable to collect
data directly on issues of interest rather than attempting
to infer or estimate from other data thought to be related
to the issue of interest. In cases where predictors are
considered essential, the functional relationships among
predictors and dependent variable(s) should be established
in advance of major data collection efforts. Multivariate
arrays, rather than isolated variables, composites or
averages should be used wherever possible.
10. In all data collection activities, the criterion of
relevance should take precedence over precision of measure-
ment. Qualitative estimation of a relevant parameter may
be of much more value than very precise measurement of a
less relevant parameter.
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APPENDIX A. SURVEY ADMINISTRATION
This appendix consists of a report on survey administration made
to the project sponsors by Survey Research Services, Inc., and the
questionnaire and map used in the field. The report on survey adminis-
tration is as submitted to the project sponsors, without editorial
modification.
The systematic random procedure used for selecting starting points
for interviewing discussed in the report consisted of the following
steps:
1. The pages of residential listings for the directory were
counted.
2. The number of pages was divided by the desired number of
key addresses or starting points for that directory to
obtain the page selection interval.
3. The starting page, a column number and a line number were
selected from a table of random numbers.
4. Beginning with the starting page, the selected line in the
selected column was taken on each selected page. Selected
pages after the starting page were obtained by adding the
page selection interval to the starting page number.
5. If the selected line contained an unsuitable address, such as
a business address or an address outside the county, the next
suitable residential address was taken.
The questionnaire, codebook, and a complete set of data cards have
been deposited in the International Data Library and Reference Service,
University of California, Berkeley, California.
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MNapa
TO Y Redwojo
S A\ N^P***.^
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SURVEY METHOD
This volume contains a description of the method followed in a survey
of public opinion on San Francisco Bay water pollution. The survey
was conducted for Mr. Gene Willeke of Stanford University by Survey
Research Services, Inc., an affiliate of Field Research Corporation,
an independent marketing and opinion research agency. Also included
are copies of the questionnaire and other field materials used.
Survey Research Services was responsible for all aspects of field
administration, coding and editing the completed questionnaires, and
preparing a final set of statistical data cards. The questionnaire
was designed jointly by SRS and Mr. Willeke.
General Approach
The survey was carried out by a face-to-face personal interview con-
ducted in respondents' homes by skilled interviewers working under the
close supervision of a senior staff member of Survey Research Services.
The interview included a broad range of techniques including structured
and "open-end" questions and a battery of attitude scale items.
Survey Area
The survey area was designated as the counties or portions of counties
of the Bay Area which were judged to lie within approximately 30 minutes
driving time from the shores of San Francisco or San Pablo Bay.
Accordingly, the survey area included all of Alameda, San Francisco,
San Mateo, and Solano Counties and parts of Contra Costa, Santa Clara,
Marin, Napa, and Sonoma Counties.
92
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The first step in the sample selection process was to outline the
desired survey area on a detailed map of the nine-county Bay Area.
Next, these rough boundaries were made to conform to appropriate census
divisions for the counties so that the population of the survey area
could be closely estimated from published population figures.
Next, the 1960 U.S. Census population was recorded for the designated
survey area within each county and the proportion that this represented
of the total county population was calculated. That percentage was
then applied to the total county population estimate for 1967 as
reported in the June 10, 1967 issue of Sales Management to arrive at
an up-to-date estimate of the current population within the survey
area of each county. The resulting figures for the survey area are
shown on the following table:
93
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Table 1.
PENINSULA
San Francisco County
San Mateo County
Santa Clara County
CCD's'' in survey area (Lexington;
Los Altos Hills-Monte Bello; Los Gatos;
Milpitas; Mtn. View-Los Altos; Palo
Alto; San Jose; Santa Clara; Saratoga)
CCD's excluded (Coyote; Gilroy;
Llagas-Uras, Morgan Hill; San Martin)
EAST BAY
Alameda County
Contra Costa County
CCD's in survey area (all except
Clay ton-Tassaj ara)
CCD's excluded (Clay ton-Tassaj ara)
1960
population
(U.S. Census)
740,316
444,387
642,315
620,362
21,953
908,209
409,030
406,767
2,263
1967 popula-
% of total tion estimate
county in (Sales
survey area Management)
100.0 730,700
100.0 537,100
942,700
96.6 910,600
3.4 32,100
100.0 1,053,000
529,000
99.3 525,300
.7 3,700
//County Census Divisions
(continued on next page)
-------
1967 popula-
vo
NORTH BAY
Marin County
CCD's in survey area (Lucas-Gallinas
Valley; Mill Valley; Northeast; Ross
Valley; San Geronimo Valley; San
Rafael; Sausalito; Tiburon)
CCD's excluded (Northwest; West)
Solano County
Sonoma County
CCD's in survey area (Petaluma;
1960
population
(U.S. Census)
146,820
142,830
3,990
134,597
147,375
119,825
% of total tion estimate
county in (Sales
survey area Management)
196,000
97.3 190,700
2.7 5,300
100.00 165,600
184,100
81.3 149,700
Petaluma rural; Santa Rosa; Santa
Rosa North; Santa Rosa South;
Sebastopol; Sonoma)
CCD's excluded (Cloverdale-Geyersville;
Healdsburg; Russian River-Coastal)
27,500
18.7
34,400
Napa County
CCD's in survey area (Angwin;
Calistoga; Napa; Napa Northwest;
Napa Northeast; Napa Southwest;
Napa West; St. Helena)
CCD's excluded (Berryessa)
65,890
65,592
298
99.5
.5
77,700
77,300
400
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Sample Size and Distribution
The total survey area was divided into three sub-areas — Peninsula,
East Bay and North Bay. To assure a large enough base of interviews to
allow data to be analyzed separately by each of these sub-areas, a
minimum number of interviews was assigned to each sub-area which did
not necessarily reflect the area's population proportion. However, the
distribution of interviews within each sub-area was proportionate to
the population distribution of the sub-area. Statistical identifiers
for each sub-area were punched into the IBM cards so that findings
based on the total sample of interviews could be weighted in tabulation
to reflect the actual distribution of population throughout the nine-
county survey area.
A total of 914 interviews was completed and tabulated. Of these 914
interviews, 465 were conducted with women and 449 with men. The
distribution of the total sample by sub-area and county is shown in
Table 2.
96
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Table 2.
Completed Interviews
Number %
PENINSULA
San Francisco County (all)
San Mateo County (all)
Santa Clara County (part)
EAST BAY
Alameda County (all)
Contra Costa County (part)
NORTH BAY
Mar in County (part)
Solano County (all)
Sonoma County (part)
Napa County (part)
384
134
90
160
326
221
105
204
70
60
50
24
100.0
34.9
23.4
41.7
100.0
67.8
32.2
100.0
34.3
29.4
24.5
11.8
Estimated 1967
Population
(Sales Management)
Number %
2.178,400
730,700
537,100
910,600
1.578.300
1,053,000
525,300
583.300
190,700
165,600
149,700
77,300
100.0
33.5
24.7
41.8
100.0
66.7
33.3
100.0
32.7
28.4
25.7
13.2
-------
Selection of Random Starting Points
Once the survey area was established, starting points for the inter-
viewing were selected by a systematic random procedure from the latest
telephone directories covering the survey area. As each random starting
point (or "key address") was drawn, it was plotted on a detailed street
map to be sure it fell within the designated boundaries of the survey
area. If it did not, it was discarded and a substitute was drawn at
random and again plotted. This procedure continued until a sufficient
number of starting points and alternates were drawn to complete the
total assignment.
Household Selection
Each interviewer's assignment was to complete five interviews within a
cluster for which the random starting point was a "key address"
selected by the method described above. The interviewer was instructed
to go to the "key address" and attempt her first interview there.
Regardless of whether or not she completed the interview, she was to
skip the house next door and make her next attempt at the third
dwelling, the next at the fifth, etc. She continued this pattern down
the street, turning left at each corner so that she stayed within the
block.
The interviewer was instructed to list and call on five addresses along
her route in accordance with the pattern described above, and to make
up to three attempts at different days and times to complete an inter-
view at each of the five addresses before selecting an alternate
address. However, alternate addresses were substituted immediately if
98
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the interviewer encountered a refusal, an unoccupied dwelling, or a non-
English speaking respondent, since these addresses would not qualify for
call-backs.
If the interviewer was unable to complete five interviewers in the
primary block following the procedure outlined above, she was instructed
to select adjacent alternate blocks in a pre-determined manner and
repeat the same pattern in these blocks.
Respondent Selection
Within each cluster of five interviews per sampling location, at least
two, but not more than three interviews were conducted with men. Any
responsible adult member of the household at home was eligible for the
interview, provided he or she met this sex quota control. It has been
demonstrated in public opinion research that younger men and older
women are the most difficult respondents to locate at home. Therefore,
at each home contacted, the interviewer asked first to speak to the
youngest man 21 or older who was at home. If no man was at home, she
asked to interview the oldest woman 21 or older who was at home. Only
one adult was interviewed within a single family or household.
Results of Household Contacts
Table 3 shows the results of the contacts made to obtain the 914 inter-
views completed and tabulated:
99
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Table 3.
Results of Household Contacts
Total households contacted one or more times
(includes call-backs)
Unoccupied dwellings
Total occupied dwellings contacted
No contact made with eligible adult
(no one home, language barrier, too
busy, etc.)
Refused (on any of three attempts)
Successful contact made with adult
Not eligible (didn't fit sex quota)
Discontinued interview or interview
not completed enough to tabulate
Interviewed
On first attempt
On second attempt
On third attempt
Number
2227
87
2140
492
660
988
65
9
914
601
201
112
Percent
100
23
31
46
3
A
43
28
9
5
*Less than 1/2 of one percent.
Interviewer Supervision
Fifty experienced members of the interviewing corps of Survey Research
Services conducted the field work for this survey. All interviewers
attended a group training session given by the Project Chief assigned
to the study. All aspects of sampling and interviewing procedures were
fully explained at this meeting, and interviewers were also given a set
of detailed, written instructions to help answer any questions which
might arise in the field.
100
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After each interviewer had completed her first day's work (or not less
than two interviews), she stopped interviewing and returned these
completed interviews to the Interviewer Training Director who personally
reviewed each one for consistency, accuracy, and understanding of all
survey procedures. Each interviewer was then notified in person or by
telephone of any problems discovered in her work and these were
corrected before she continued with her full assignment.
Verification
Approximately 20% of each interviewer's assignment was verified by re-
contacting her respondents by telephone to be sure that (a) the inter-
view was actually made with the respondent, (b) the interviewer was
polite and courteous, and (c) the interviewing procedure was carried
out according to survey specifications. All interviewers' work was
found to be valid and authentic.
Questionnaire Development^
Several different drafts of the qustionnaire were prepared and pre-
tested with eligible respondents within the survey area. After each
pre-test, revisions were made in question wording and certain question
areas were added or deleted to arrive at a final questionnaire which
would run smoothly and generate the data required by the objectives
set by Mr. Willeke.
Tabulation
After all the assignments were verified, the questionnaires were
edited for completeness and consistency by the coding staff and pre-
101
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liminary answer categories were set up for coding the free-response
questions. These answer categories were reviewed and approved by
Mr. Willeke before any coding was undertaken.
The coded questionnaire data were then transferred to punched data cards
and these cards were checked closely for accuracy and consistency on an
IBM 1130 Computer with a special card cleaning program. The final set
of data cards was then turned over to Mr. Willeke. This completed the
project responsibility assigned to Survey Research Services.
Statistical Reliability
In any survey based on a sampling, there is some unreliability intro-
duced into the data by the process of sampling itself. If the sample
has been drawn according to strict random processes, it is possible to
apply probability principles to determine the potential range of such
error. However, while survey samples of human populations rarely, if
ever, meet all of the criteria theoretically required for the applica-
tion of these principles, it is customary to use them as an approxima-
tion of the error that is introduced as a result of sampling.
The table below shows the range of error that is associated with
samples of various sizes, assuming the use of the 95% confidence level,
which is customary for surveys of this type. For example, a statistic
from this survey based on a group of 250 respondents is subject to a
sampling variance of 4 to 6 percentage points, plus or minus. Thus, if
the survey statistic shows 55% answering "yes", then we can have 95%
confidence that the "true" figure would be found between 61% and 49%.
102
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Likewise, if the statistic were 90% answering "yes", the "true" figure
might be found anywhere between 86% and 94% with 95% certainty.
Table 4a.
Sampling Variability of Individual Percentages
When the percentage in question is as follows,
the chances are about 19 out of 20 (95%) that
the "true"* value of the statistic would be
found within plus or minus the number of per-
centage points shown below for that size of
base
Size of base on
which percentage
is computed
50
100
150
200
250
400
750
1000
When
About
14
10
8
7
6
5
3
3
the percentage figure is:
Closer to
50% 70% or 30%
13
9
7.
6.
6
4.
.6 3.
.2 2.
5
5
5
3
9
Closer
90% or
8.
6
5
4
4
3
2.
1.
5
2
9
to
10%
*(The "true value" is the value that would be obtained by interviewing
the total population of adults with the techniques used here.)
To determine whether two percentages are significantly different,
another formula is used. Table 4b. shows the differences which must
exist between two percentages derived from independent subsamples of
the survey before they can be considered to indicate a real difference
between the groups being compared.
103
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Table 4b.
Levels of Significance for Differences Between Percentages
When two percentages are compared from
different subgroups of the same survey
or from different surveys, the chances
are 19 out of 20 (95%) that the differ-
Number of cases is the ence between them is significant if it
smaller of the groups is greater than the amounts noted below:
being compared Percentage points:
50 15 - 19
100 9 _ 1A
150 8 - 11
200 7 _ 10
400 4.5 _ 7
600 3.5 _ 5.8
800 3 _ 5
1000 2.7 - 4.2
(The lower end of this range applies to statistics near 90% or 10%; the
higher end of the range to percentages near 50%.)
In using these estimates of sampling variance, it is important to
realize that sampling error is only one of the influences which may
affect survey results. Other things, such as question wording, inter-
viewer influence on respondents, etc., can cause variances in results
which are often of a magnitude many times larger than any sampling
errors. For this reason, the sampling error figures shown here should
be used with due regard for their limitations.
Survey Dates
All interviewing was conducted between September 25 and October 20,
1967.
104
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Survey Research Services, Inc
145 Montgomery Street
San Francisco, Calif. 94104
BAY AREA OPINION SURVEY
y-2560
091467
Final
Time began:
Hello. I'm
from Survey Research Services. We're doing a survey in this area and I'd like
to get your opinions on some matters of interest to people living in the Bay Area.
First of all, have you always lived in the
Bay Area, or did you live elsewhere
before coming to the Bay Area ?
(IF "LIVED ELSEWHERE." ASK);
ALWAYS LIVED HERE
LIVED ELSEWHERE
1 (GOTOQ. 3)
2 (ASK Q. 2a)
la,
Where did you live before coming
to the Bay Area ?
OTHER U.S. STATE
OUTSIDE OF U.S.A. . .
OTHER NORTHERN CALIF.
OTHER SOUTHERN CALIF.
(GOTOQ. 2c)
(ASK Q 2b)_
(IF "OUTSIDE" OR "OTHER NORTHERN" OR "SOUTHERN CALIF." ASK):
2b. Have you ever lived in another
part of the United States?
YES
NO
2c.
About how long, in total, have
you lived in the Bay Area ?
LESS THAN 1 YEAR .... '^'1
1 YEAR - 2.9 YEARS 2
3 YEARS -4.9 YEARS 3
5 YEARS - 9. 9 YEARS 4
10 YEARS OR MORE 5
4.
About how often do you see or look at any part
of either San Francisco Bay or San Pablo Bay?
EVERY DAY /?- . 1
TWO OR THREE TIMES A WEEK . . .2
ABOUT ONCE A WEEK 3
2-3 TIMES A MONTH 4
ABOUT ONCE A MONTH 5
LESS OFTEN THAN ONCE A MO. . .6
What are the most appealing things to you about the San Francisco Bay itself? What are the things
you like about it? (PROBE) What else?
What are the most unappealing things about the Bay ? What do you dislike about the Bay ?
(PROBE) What else?
105
1*1-
-------
6. Have you gone boating or sailing anywhere YES . ?". 1 (ASK Q. 7 SERIES)
within the past year? NO . . .X (SKIP TO Q 8a NEXT PAGE)
(IF "YES" TO QUES 6, ASK).
7a. How many different days have you been
boating or sailing within the past year?
(Total days)
7b. (HAND CARD A) Please look at this card and tell me all the places you've been
boating or sailing within the past year. (RECORD BELOW)
7c. (FOR EACH PLACE MENTIONED IN QUES. 7b): On how many different
days did you go boating or sailing there in the past year? (RECORD BELOW) - •
(Q- 7c)
(Q. 7b) NO OF DAVS
PLACES WENT BOATING OR SAILING WENT THERE
Anywhere on Bay ........... ' ...... _ __"
Lake Berryessa .... ...... 2 ...... _
Clear Lake ............ 3 ...... _
Lake Tahoe ............ 4 ...... _ _
Other Northern Calif, waters _ ___ • • _ __
(specify)
Other Northern Calif, waters ___ • • _ 2i"
(specify)
Southern Calif, waters . ...... 5
Outside of Calif . waters ........ 6
(IF "ANYWHERE ON BAY" MENTIONED IN QUES. 7b, HAND MAP TO RESPONDENT):
7d. Looking at this map of the Bay Area, please ZONE A . . . 2 . 1
tell me where you usually go boating or ZONE B . . - • /
sailing in the Bay. ZONE C ... .3
ZONE D .... 4
(IF BAY NOT MENTIONED IN QUES 7b, ASK):
7e. Is there any particular reason why you haven't gone boating or sailing on the Bay within the
past year? (PROBE)
INTERVIEWER: REFER TO Q 7c ABOVE IF RESPONDENT BOATS OR SAILS ANYWHERE ON BAY
BUT NO OF DAYS ON THE BAY ARE LESS THAN 1/2 OF TOTAL DAYS IN Q 7a, ASK:
7f. I see that you went boating or sailing on the Bay less than half the time. Is there any particular
reason why you didn't go on the Bay more often? (PROBE)
106 I NOW SKIP TO Q. 9
-------
(IF "NO" TO QUES. 6, ASK):
8a. Have you ever been boating or sailing on San Francisco or San Pablo Bay?
YES ... r .1 (ASK 8b) -^ NO 2 (ASK 8c)
8b. Is there any particular reason why you
haven't been boating or sailing on the
Bay in the past year?
(NOW SKIP TO Q. 9)
8c. Would you personally be interested in going
boating or sailing on the Bay?
YES. . ? 1 (ASK 8d) NO. . .2 (ASK 8e)-
8d. Is there any particular reason why
you haven't been?
(NOW SKIP TO Q. 9)
8e. Why is that? Any particular reason
(NOWSKIPTO Q. 9)
107
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9 Have you gone swimming an^^he e except at
swimming pools within the past year?
(IF "YES" TQ Q. 9, ASK).
YES
NO
.X
(ASK QUES, 10 SERIES)
(SKIP TO Q lla NEXT PAGE;-
lOa- How many different days have you been swimming
within the past year, not counting in swimming pools?
(Total days)
lOb. (HAND CARD A) Please look at this card and tell me all the places you've been
swimming within the past year. (RECORD BELOW)
(FOR EACH PLACE MENT!ONED IN QUES. lOb.): On how many different
days did you go shimming there in the past year? (RECORD BELOW)
(Q lOb)
PLACES WENT SWIMMING
(Q 10c)
NO OF DAYS
WENT THERE
Anywhere on Bay ' •
Lake Berryessa 2 .
Clear Lake .,.,.-•• 3 ,
Lake Tahoe • 4
Other Northern Calif waters
Other Northern Calif, waters
3v
(specify)
(specify)
Southern Calif, waters . 5
Outside of Calif, waters -6
(IF "ANYWHERE ON BAY" MENTIONED IN QUES. lOb, HAND MAP TO RESPONDENT):
lOd. Looking at this map of the Bay Area, please tell ZONE A ... .1
me where you usually go swimming in the Bay. ZONE 0 .... 2
ZONE C .... 3
ZONED ... .4
(IF BAY NOT MENTIONED IN QUES 1 Ob, ASK):
lOe. Is there any particular reason why you haven't gone swimming in the Bay within the past year?
(PROBE)
INTERVIEWER: REFER TO Q lOc ABOVE IF RESPONDENT SWIMS ANYWHERE IN BAY. BUT NO
OF DAYS IN THE BAY ARE LESS THAN 1/2 OF TOTAL DAYS IN Q lOa, ASK:
10f. I see that you went swimming in the Bay less than half the time. Is there any particular reason
why you didn't go in the Bay more often? (PROBE)
108
NOW SKIP TO Q 12
-------
(IF "NO" TO QUES. 9, ASK):
Ha. Have you ever been swimming in San Francisco or San Pablo Bay?
YES . . .^ 1 (ASK lib) -, NO ... 2 (ASK lie)
lb. Is there any particular reason why you
haven't been swimming in the Bay in
the past year?
it*'
(NOW SKIP TO Q. 12)
lie. Would you personally be interested in
swimming in the Bay?
YES. .*. 1 (ASK lid) NO . . 2 (ASK lie)-,
lid. Is there any particular reason why
you haven't been?
St,
(NOW SKIP TO Q.12)
lie. Why is that? Any particular reason?
(NOW SKIP TO Q. 12)
109
-------
12 Have you personally gone water skiing anywhere YES . . *' 1 (ASK QUES. 13 SERIES)
within the past year? NO . . . X (SKIP TO Q. 14a NEXT PAGE)
(IF "YES" TO QUES. 12, ASK):
13a. How many different days have you been
water skiing within the past year?
(Total days) sv
13b. (HAND CARD A) Please look at this card and tell me all the places you've
been water skiing within the past year. (RECORD BELOW)
13c. (FOR EACH PLACE MENTIONED IN QUES. 13b): On how many different
days did you go water skiing there in the past year? (RECORD BELOW) J,
(Q. 13c)
(Q. 13b) NO. OF DAYS
PLACES WENT WATER SKIING WENT THERE
Anywhere on Bay ............ 1
Lake Berryessa ............. 2
Clear Lake .............. 3
Lake Tahoe .............. 4
Other Northern Calif, waters
_
(specify)
Other Northern Calif, waters
(specify)
Southern Calif, waters 5
Outside of Calif, waters 6
(IF "ANYWHERE ON BAY" MENTIONED IN QUES. 13b, HAND MAP TO RESPONDENT):
13d. Looking at this map of the Bay Area, please tell ZONE A . . .
-------
(IF "NO" TO QUES. 12, ASK):
\4a. Have you ever been water skiing on San Francisco or San Pablo Bay?
YES ... fl (ASK Q. 14b) -?• NO. ... 2 (ASK Q. I4c)
14b. Is there any particular reason why you
haven't been water skiing on the Bay
in the past year?
(NOW SKIP TO Q. 15)
14c. Would you personally be interested in water
skiing on the Bay?
YES. . .1 (ASK 14d) NO. . .2 (ASK 14e)—,
14d. Is there any particular reason why
you haven't been?
(NOW SKIP TO Q.15)
14e. Why is that? Any particular reason?
(NOW SKIP TO Q. 15)
111
-------
15. Have you gone fishing anywhere within
the past year?
(IF "YES" TO QUES. 15, ASK):
YES . .'V 1 (ASK QUES. 16 SERIES)
NO ... X (SKIP TO Q. 17a NEXT PAGE)-
I6a. How many different days have you been fishing
within the past year?
16b. (HAND CARD A) Please look at this card and tell me all the places you've
been fishing within the past year. (RECORD BELOW)
16c. (FOR EACH PLACE MENTIONED IN QUES. 16b): On how many different
days did you go fishing there in the past year? (RECORD BELOW)
(Q. 16b)
PLACES WENT FISHING
(Total days)
(Q. 16c)
NO. OF DAYS
WENT THERE
Anywhere on Bay 1
Lake Berryessa 2
Clear Lake 3
Lake Tahoe 4
Other Northern Calif, waters
(specify)
Other Northern Calif, waters
(specify)
Southern Calif, waters 5
Outside of Calif, waters 6
(IF "ANYWHERE ON BAY" MENTIONED IN QUES. 16b, HAND MAP TO RESPONDENT):
16d. Looking at this map of the Bay Area, please tell ZONE A . . -'1
me where you usually go fishing in the Bay. ZONE B . . . 2
ZONEC ... 3
ZONE D . . - 4
(IF BAY NOT MENTIONED IN QUES 16b, ASK):
16e. Is there any particular reason why you haven't gone fishing in the Bay within the past year?
(PROBE)
INTERVIEWER: REFER TO Q 16c ABOVE. IF RESPONDENT FISHES ANYWHERE IN BAY, BUT
NO OF DAYS IN THE BAY ARE LESS THAN 1/2 OF TOTAL DAYS IN Q. 16a, ASK:
16f. I see that you went fishing in the Bay less than half the time. Is there any particular reason
why you didn't go in the Bay more often? (PROBE)
112
11-
NOW SKIP TO QUES. l&a
-------
(IF "NO" TO QUES 15, ASK):
17o. Hove you ever been fishing in San Francisco or San Pablo Bay?
YES. . . 1 (ASK Q. 17b)
NO
2 (ASK Q. 17c)
17b. Is there any particular reason why you
haven't been fishing in the Bay in the
past year?
(NOW SKIP TO Q. IB)
17c. Would you personally be interested in fishing
in the Bay?
•HT
YES. . .1 (ASK 17d) NO. . 2 (ASK 17e)-
V
17d. Is there any particular reason why
you haven't been?
(NOW SKIP TO Q. 18)
17e. Why is that? Any particular reason?
(NOW SKIP TO Q 18)
113
-------
ASK EVERYONE
18a. Would you eat fish which were
caught in the Bay?
YES . . . . T'. 1
QUALIFIED . . .21
NO ...... 3 "T
(SKIP TO Q. 19)
(ASK Q. 18b)
(IF "QUALIFIED" OR "NO" TO QUES. 18o, ASK):
18b. Why is that?
19.
20a.
(HAND CARD B) Do you personally engage in any
of these other recreational activities around the
shoreline of the Bay? (IF YES) Which ones?
HIKING OR WALKING - . . ."'.I
BIRD WATCHING 2
PICNICKING 3
WADING 4
SUNBATHING 5
OTHER: . 6
(specify)
NO, NONE OF THESE 0
At the present time, do you feel that
contact with Bay water could be
harmful to a person in any way?
(IF "YES" TO QUES. 20a, ASK):
YES «•: 1
NO 2
DON'T KNOW, NOT SURE, 3
(ASK Q 20b & c)
(SKIP TO Q.21a)
20b. In what way do you think it
could be harmful? (DO NOT
READ LIST CIRCLE ANY
ANSWERS MENTIONED OR
WRITE IN UNDER "OTHER")
20c. How harmful do you think it could
be? Would you say it could be ..
(READ CATEGORIES)
CAUSES SKIN RASH OR IRRITATION
CAUSES NAUSEA/DIARRHEA . . .
MAKES YOU SICK (NOT SPECIFIC)
OTHER (specify)
2
3
DON'T KNOW, NOT SURE 0
EXTREMELY HARMFUL . . . *.' 1
SOMEWHAT HARMFUL .... 2
ONLY SLIGHTLY HARMFUL ... 3
2Ia.
To the best of your knowledge, have you
personally ever become ill or suffered
any harmful effects from Bay water?
(IF "YES" TO QUES. 21a, ASK):
YES *?' 1
NO 2
DON'T KNOW, NOT SURE. 3
(ASK Q 21b)
(SKIP TO Q.22a)->
21a. In what way? (DO NOT READ LIST.
CIRCLE ANY ANSWERS MENTIONED
OR WRITE IN UNDER "OTHER")
SKIN RASH OR IRRITATION . . 34. 1
NAUSEA/DIARRHEA 2
OTHER (specify)
114
-------
22a.
Have you ever heard that San
Francisco Bay is polluted?
(IF "YES" TO QUES. 22a, ASK):
22b. How long ago did you first hear this?
YES *M (ASKQ. 22b, c&d)
DON'T KNOW, NOT SURE.' ! jf <^P TOQ.23)
22c. Where did you first hear this?
22d. Do you recall what they said
caused the Bay to be polluted?
(DO NOT READ LIST)
WITHIN THE PAST MONTH . . . .*: 1
ONE - SIX MONTHS AGO ... 2
7 MONTHS -ONE YEAR AGO . . 3
1.1-5 YEARS AGO 4
5.1 - 10 YEARS AGO 5
MORE THAN 10 YEARS AGO .... 6
TV PROGRAM *: 1
RADIO 2
NEWSPAPER 3
MAGAZINE, BOOK 4
ORGANIZATION MEETING .... 5
FRIEND, RELATIVE 6
OTHER:___
DON'T KNOW, NOT SURE 0
CITY SEWERS *'.' 1
INDUSTRIAL CHEMICALS AND
WASTES 2
AGRICULTURAL RUN-OFF 3
GARBAGE DUMPING/BAY FILL ... 4
BOAT WASTES 5
OT HE R;
DON'T KNOW, NOT SURE 0
23.
What do you think of when someone mentions pollution of San Francisco Bay? (PROBE) What
does Bay pollution suggest to you? What does that mean?
24 How do you think someone could tell (would know) whether the Bay were polluted or not?
would be the signs of pollution? (PROBE) What would you look for (or expect to see?)
It-
What
25. How much do you personally care whether
or not the San Francisco Bay is polluted?
Would you say you care ~ (READ LIST)
A GREAT DEAL «*.' 1
SOMEWHAT 2
NOT VERY MUCH 3
HARDLY ANY 4
115
-------
26a . Do you think San Francisco
Bay is polluted now?
YES *?' 1
NO 2
DON'T KNOW, NOT SURE. 0
(GO TO Q. 26b)
(SKIP TO Q. 27o —
NEXT PAGE)
(IF "YES" TO QUES. 26a, ASK):
26b. How polluted do you think it is?
Would you say it is ...
(READ CATEGORIES)
26c. Wiat do you think causes San
Francisco Bay to be polluted?
(DO NOT READ LIST)
EXTREMELY POLLUTED . . . *f- I
SOMEWHAT POLLUTED .... 2
ONLY SLIGHTLY POLLUTED . . 3
CITY SEWERS ...."> I
INDUSTRIAL WASTES AND CHEMICALS ... 2
AGRICULTURAL RUN-OFF 3
GARBAGE DUMPING/BAY FILL 4
BOAT WASTES 5
OTHER
DON'T KNOW 0
26d. Do you think that San Francisco
Bay con be cleaned up or not?
YES V
NO
DON'T KNOW, NOT SURE.
(GO TO Q. 26f)
(ASK Q. 26e)
(IF "NO" OR "DON'T KNOW", ASK):
26e. Why is that? Why not?
26f. Do you think San Francisco Bay
will be cleaned up?
YES 'l
NO 2
DON'T KNOW, NOT SURE. 0
(SKIP TO Q. 27a)—>
(ASK Q 26g)
(IF "NO" OR DON'T KNOW", ASK):
26g. Why is that? Why not?
116
-------
27a. Do you remember seeing or hearing anything
recently about Bay pollution or Bay fill...
either on TV, the radio, or newspapers, or
somewhere else?
(IF "YES" TO QUES 27a, ASK).-
YES
NO
1 (GO TO Q.. 27b)
X (SKIP TO Q, 28a)
27b. What did you see or hear about the Bay? (PROBE): What was it about? What was
said or shown?
27c. If you wanted to find out more about this (these) issue(s), what would you do?
28a. Have you ever attended any meetings where
Bay pollution or Bay fill was discussed?
(IF "YES" TO Q 28a, ASK):
YES
NO
X
(ASK Q, 28b)
(SKIP TO Q.29)-
28b. What type of organization was that?
CIVIC 1
CONSERVATION ...... 2
GOVERNMENT ...... 3
OTHER
(specify)
28c. What was discussed at the meeting?
si-
-------
29.
30.
31
Overall, how much would you say you have
seen or heard about Bay pollution or Bay fill?
Would you say you have seen or heard ...
(READ CATEGORIES)
Do you feel that you have received as much information about
Bay pollution or Bay fill as you would like to have?
A GREAT DEAL .
SOMEWHAT . .
NOT VERY MUCH.
HARDLY ANY . .
1
2
3
4
YES
NO
(HAND CARD C) As you see it, whose
responsibility is it to see that the public
gets information about the Bay?
RADIO AND TV .u'. 1
NEWSPAPERS 2
MAGAZINES 3
CIVIC AND CONSERVATION
ORGANIZATIONS ....
LOCAL GOVERNMENT. . . .
STATE GOVERNMENT ....
FEDERAL GOVERNMENT . . .
MARINE OR WATER EXPERTS . .
OTHERS
4
5
6
7
E
32. Now suppose you were interested in finding out more about the Bay. Using this card (HAND CARD
D) tell me how much you would rely on each source of information I'm going to mention. Assume
that you have not formed any opinion yourself yet and you just want to know more about the matter.
How much would you rely on —
Very Fairly I'd be I would be
reli- reli- cautious quite skep-
able able of this tical of Don't
source source source this source know
a. Official statements from the federal
b.
C .
d.
e.
f.
Statements by independent scientific
experts ^?" . 1 .
Television documentaries 1 .
. 2 . .
. 2 . .
. 2 .
2
.2 .
. . 3 . .
. . 3 . .
. .3. .
3 . .
.3. .
4
. 4 .
4
. 4 .
. 4.
. . 0
. . 0
. . 0
. . 0
. . 0
Statements by private conservation
organizations - ....... .**"''. 1 ... 2 . . . 3 . . . 4 . . . 0
h. Official statements from the local government. A'. 1 .
4.
118
-------
33. (HAND CARD E) Do you belong to
any of these organizations?
SIERRA CLUB ." 1
SAVE THE REDWOODS LEAGUE 2
SAVE SAN FRANCISCO BAY ASSOC. ... 3
THE AUDUBON SOCIETY 4
IZAAK WALTON LEAGUE 5
NO, NONE OF THESE 0
ANSWER FOLLOWING QUESTIONS ABOUT EACH ORGANIZATION BELONGED TO:
(Name of organization)
Do you give any financial support to this
organization? (IF YES) About how much
money a year?
Have you ever written any letters to
legislators at the request of this organization?
About how often do you attend their
meetings?
DO NOT GIVE ANY .
YES .
NO .
VERY INFREQUENTLY
OCCASIONALLY .
1
2
REGULARLY 3
(Name of organization)
Do you give any financial support to this
organization? (IF YES) About how much
money a year?
Have you ever written any letters to
legislators at the request of this organization?
About how often do you attend their
meetings?
DO NOT GIVE ANY. . . . 0
YES .... 1
NO .... 2
VERY INFREQUENTLY ... 1
OCCASIONALLY .... 2
REGULARLY 3
ASK EVERYONE
34. (REFER TO CARD E) Do you happen to
know whether any of these organizations
has taken a public position on (anything
about) San Francisco Bay? (!F YES)
Which organizations?
SIERRA CLUB 1
SAVE THE REDWOODS LEAGUE .... 2
SAVE SAN FRANCISCO BAY ASSOC. . - 3
THE AUDUBON SOCIETY 4
IZAAK WALTON LEAGUE 5
NO, NONE HAVE 9
DON'T KNOW 0
119
(CONTINUED)
-------
35. ASK FOLLOWING QUESTIONS ABOUT EACH ORGANIZATION MENTIONED IN Q 34 & FILL
IN BELOW:
a W^at position have they taken?
b. Do you agree or disagree with this position?
t
Name Name ! Name
a Position;
b. AGREE STRONGLY . . 1
AGREE SOMEWHAT ... 2
DISAGREE SOMEWHAT . 3
DISAGREE STRONGLY 4
1
a. Position.
b. AGREE STRONGLY . 1
AGREE SOMEWHAT ... 2
DISAGREE SOMEWHAT . 3
DISAGREE STRONGLY . 4
a. Position-
b. AGREE STRONGLY . .
AGREE SOMEWHAT .
DISAGREE SOMEWHAT
DISAGREE STRONGLv
i_— _ .
1
. 2
3
4
36. (HAND RESPONDENT BUFF SHEET) Now, some questions on other subjects. Wou'd you please
take this sheet, read the instructions at the top, and then answer the questions as you come to
them. Remember, there are no right or wrong answers, just opinions.
WHEN RESPONDENT FINISHED.. TAKE BACK BUFF SHEET, RECORD
INTERVIEW NUMBER ON BACK^ AND ATTACH SHEET TO THIS
QUESTIONNAIRE
Now, just a few final questions for classification purposes . . .
37. Would you say your own health, in general, is
(READ CATEGORIES AND CIRCLE ONE)
38. Do you have any physical handicaps that limit
you1" recreational activities in any major way?
39. During a typical week, about how many hours
do you spend on outdoor recreation of any
kind? Just your best estimate .
EXCELLENT
GOOD .
FAIR . .
POOR . .
YES
NO
NONE
LESS THAN 1 HOUR . .
1 HOUR TO 1 .9 HOURS .
2 HOURS TO 3.9 HOURS
4 HOURS TO 59 HOURS .
6 HOURS TO 7.9 HOURS
8 HOURS TO 9.9 HOURS .
10 HOURS TO 14.9 HOURS
15 HOURS TO 19.9 HOURS
20 OR MORE HOURS
2
3
4
5
6
7
8
9
0
120
-------
40. Are you the chief wage earner for this household
or is someone else?
RESPONDENT !S ,
SOMEONE ELSE IS
. 2
(ASK FOLLOWING QUESTIONS ABOUT CHIEF WAGE EARNER)
41a. What is the occupation of the chief wage
earner? What type of work does (he)(she) do?
41b. What industry or service does (he)(she) work in?
41c. U (he)(she) employed at the moment—
either full time or part time?
(type of work)
(industry or service)
EMPLOYED FULL-TIME . .
EMPLOYED PART-TIME . .
NOT EMPLOYED . . .
2
0
42a. Counting yourself, how many people live in
this household?
b. How many are adults over 18?
c. How many are teenagers 13 - 18?
d. How many are children 12 or under?
(Total in household)
(Adults)
ti'
(Teenagers)
(Children 12 or under)
43. What is your approximate age? UNDER 25 . . . .*'. 1
25-34 2
35-44 3
45-54 4
55-64 5
65 OR OLDER ... .6
44. What is your marital status? SINGLE, NEVER MARRIED s". 1
SEPARATED, DIVORCED OR WIDOWED . .2
MARRIED 3
45. What is the last grade of school LESS THAN HIGH SCHOOL <-7'. i
you completed? SOME HIGH SCHOOL, NOT
COMPLETED 2
COMPLETED HIGH SCHOOL 3
SOME COLLEGE, BUSINESS, OR
TECHNICAL SCHOOL 4
COLLEGE GRADUATE 5
POST COLLEGE GRADUATE WORK . . .6
46. Now, we need a rough idea of your income UNDER 55,000 .... V. \
We don't care to know your exact income, but $5,000 - $7,499 2
would you please look at this card and tell me $7,500 - $9,999 3
which amount comes closest to the total com- $10,000 - $14,999 4
bined yearly income, before taxes, of your $15,000 - $19,999 ..... 5
household... include all members who work. $20,000 - $24,999 6
(HAND CARD F) $25,000 OR MORE .7
(specify amt)
REFUSED X
121
-------
May I ask your name and telephone number, just so my supervisor could verify that I did this interview
correctly.
Name of respondent: Phone:
Address: City:
INTERVIEWER: IF RESPONDENT REFUSES TELEPHONE NUMBER, PLEASE ASK
WHETHER OR NOT HE/SHE HAS A TELEPHONE AND INDICATE HERE.
HAVE TELEPHONE s* 1
DO NOT HAVE TELEPHONE ... 2
INTERVIEWER: RECORD FROM OBSERVATION ONLY
49. Type of dwelling SINGLE-FAMILY HOUSE . . . v>' 1
MULTI-FAMILY HOUSE
(DUPLEX, TRIPLEX) ..... 2
APARTMENT, FLAT ...... 3
OTHER
50. Ethnic group of respondent: WHITE , >" . I
NEGRO 2
ORIENTAL 3
OTHER 4
(specify)
51. Sex of respondent: MALE • •
FEMALE .
I certify this to be a true account of this interview:
(interviewer signature)
Date: ,-
~ Census tract
Time completed: f°r this interview
Interview Number
FOR OFFICE USE.
Verified by Date: .
Remarks:
122
-------
Y-2560
Final
QUESTION 36
Please make one check mark H for each statement to indicate how strongly you agree or disagree
with it. If you really can't make up your mind, check the middle box for "undecided." Leave no
blanks.
All the statements are matters of opinion and might be answered by different people in different ways.
There are no "right" or "wrong" answers, just opinions.
Just answer each question as it comes, without spending a lot of time on any one question
Agree
Strongly
Agree
Unde- Strongly
cided Disagree Disagree
1. One desirable feature of regional
government for the Bay Area is that it
keeps the solution of problems close
to home rather than in Sacramento or
Washington O....O....O....a....U
2. A government agency should decide how
clean the water in San Francisco Bay
should be rather than local citizen
groups . . . . _ a .... a .... D .... n .... n
3. If a city feels that the State has taken
an unreasonable position, the State should
be willing to compromise D . . . . d • • • • LJ
4. A developer who wants to fill part of the
Bay is justified because opposing govern-
ment agencies and conservationists just
have an extreme point of view D....D....D....U....
5. The details of government should be left
to the experts, so that the public
doesn't have to worry about them ....n....U....U.... ....
6. Events in the future are so uncertain
that we should only be concerned with
the present U . . . . U
7. It's all right to keep a few redwood trees
around to look at but their most important
. f i L n D ..D....D.---U
use is for lumber L_I ....<_•..
8. Technology is advancing so rapidly that
we shouldn't worry about using up our n
• n D....O....U....U
natural resources i_i . . .
123
PLEASE CONTINUE ON BACK
-------
Strongly Unde-
Agree Agree cided
Strongly
Disagree Disagree
9. It doesn't pay to plan ahead more than
a year or two these days because the
world is changing so fast D....D....D....n....n
10. You can say all you want about beauty,
but if no one will buy it, it's worthless ...D....D....D....n....n
11. The Bay Area is a wonderful place to
live and should stay just as it is .... D .... D .... D .... D .... D
12. The world will probably be destroyed
within the next 20 years D....D....D....D....D
13. Rather than waiting to find the one best
method, pollution control administrators
should take snort-range action to improve
the condition of the Bay D....D....D....D....D
14. We should try to solve the problems which
are important to us and let our children
solve theirs when their time comes ....D....D....n....D....D
15. We should be willing to make some
sacrifices now to save our natural resources .D....D....D....D....D
16. Local city councils usually aren't com-
petent to solve complex urban problems ...D....D....C3....n....C]
17. I would be willing to donate one day a
month in the summer to help clean up
beaches D D....D....D....n
18. People who don't make long-range plans
are going to regret it later on . ... D .... D .... L-J •••• 0 .... U
19. Our streams and lakes should be clean
whether or not we use them ....O....O....O....O....O
Interviewer:
Interview Number:
124
-------
APPENDIX B. DATA SUMMARY
This appendix contains the unweighted marginal percentages for the
full 914 case sample. The questions have been grouped to put similar
questions together, and to make a more concise summary. In many
instances, percentages have been rounded to the nearest full percent.
An asterisk denotes a figure less than 0.5 percent. In some cases,
where multiple responses were possible, totals exceed 100 percent. In
others, where multiple responses were not possible, totals may not
equal 100 percent because of rounding. Additional explanatory notes
are given in the text.
DEMOGRAPHIC CHARACTERISTICS
Q. 1 Have you always lived in the Bay Area, or did you live else-
where before coming to the Bay Area?
Always lived here .............. 29%
Lived elsewhere ............... 71
Q. 2a If lived elsewhere in Q. 1, where did you live before coming
to the Bay Area?
Other U.S. State .............. 45% (63%)**
Southern Calif ................ 10 (14 )
Other Northern Calif ............. 9 (13 )
Outside of U.S. A ............... 7 (10 )
**Percentages of those who had lived elsewhere before coming to the
Bay Area.
Q. 2b If outside U.S.A. or other Northern or Southern California in
Q. 2a, have you ever lived in another part of the U.S.?
11% (42%)**
Yes
No
No answer .................. '
125
-------
**Percentages of those who had lived Outside U.S.A. or in other
Northern or Southern California.
Q. 2c About how long, in total, have you lived in the Bay Area?
Less than 1 year ..... . ......... 4%
1 year-2.9 years ............... 6
3 years-4.9 years .............. 7
5 years-9.9 years .............. 9
10 years or more .......... ..... 73
No answer .................. 1
Q. 37 Would you say your own health, in general is
Excellent .................. 45%
Good ..................... 38
Fair ..................... 13
Poor ..................... 4
No answer .................. 1
Q. 38 Do you have any physical handicaps that limit your recreational
activities in any major way?
Yes .....................
No ...................... 80
No answer .................. 3
Q. 40 Are you the chief wage earner for this household or is someone
else?
Respondent is ................ 62%
Someone else is ............... 38
Q. 45 What is the last grade of school you completed?
Less than high school ............ 12%
Some high school, not completed ....... 14
Completed high school ............ 30
126
-------
Some college, business, or
technical school 26%
College graduate 10
Post college graduate work 7
No answer 1
Q. 46 Total combined yearly household income, before taxes.
Under $5,000 20%
$5,000-$7,499 18
$7,500-$9,999 18
$10,000-$14,999 23
$15,000-$19,999 8
$20,000-$24,999 2
$25,000 or more 1
Refused 9
Q. 48 Do you have a telephone?
Have a telephone 95%
Do not have telephone 5
No answer
Q. 49 Type of dwelling
Single-family house 75%
Multi-family house 6
Apartment, flat 18
Other *
No answer ^
Q. 50 Ethnic group of respondent
White
127
-------
Negro 4%
Oriental 3
Other 2
No answer 1
Q. 51 Sex of respondent
Male 49%
Female 51
Q. 41a What is the occupation of the chief wage earner and what indus-
& b try or service does he work in?
Professional and technical 18%
Managers, officials, and proprietors 13
Clerical 8
Sales workers 6
Craftsmen, foremen, skilled manual
workers 19
Operatives, semi-skilled 9
Service workers 7
Laborers 3
Student, unemployed 1
Retired, pensioner, not in labor
force, widow 16
No answer 1
Q. 41c Is the chief wage earner employed at the moment—either full
time or part time?
Employed full time 69%
Employed part time ..... 4
Not employed 21
No answer 6
128
-------
Q. 42 Household composition
No. of
Persons
0
1
2
3
4
5
6
7
8
9
10
NA
Total
Persons in
Household
0%
11
29
19
21
11
3
2
1
*
1
*
Adults
over 18
0%
15
67
13
3
*
*
*
A
0
*
*
Teenagers
13-18
76%
15
7
2
*
0
*
0
0
0
0
*
Children
12 or
under
59%
15
14
6
3
1
*
*
0
0
*
*
Q. 43 What is your approximate age?
Under 25
25-34
35-44
11%
21
20
129
-------
45-54 18%
55-64 12
65 or older 15
No answer 2
Q. 44 What is your marital status?
Single, never married 12%
Separated, divorced, or widowed 16
Married 72
No answer *
APPEALING AND UNAPPEALING ASPECTS OF THE BAY
Q. 4 What are the most appealing things to you about the San
Francisco Bay itself?
Q. 5 What are the most unappealing things to you about the San
Francisco Bay itself?
Appealing Unappealing
Climate 9% .... 6%
View 72 .... 8
Recreation opportunities .... 13 .... 5
Water characteristics (other
than quality) 23 .... 10
Commercial factors 5 .... 8
Water pollution 0 .... 51
All other and irrelevant
responses 3 .... 4
Nothing in particular 8
28
130
-------
PARTICIPATION IN RECREATION ACTIVITIES
Q. 6, 9, 12, and 15 Have you gone
anywhere in the past year?
Yes No
Boating or Sailing 27% 73%
Swimming 30 70
Water Skiing 7 93
Fishing 28 72
Q. 7» 10, 13, and 16, part a. How many days did you
_in the past
year;
Number of Days
Activity
Boat or Sail . . . 16%
Swim 11
Water Ski . . .
Fish 12
Q. 7, 10, 13, and 16, parts b and c. How many days did you pn_
in the past year?
1-4
16% .
11 .
4 .
12 .
5-9 10-19 20 or more
. . 3% . . .
. . 7 ...
. . 1 ...
• • o • • •
3% ....
6 ....
1 ....
5 ....
5%
7
1
5
Activity
Number of Days
S.F. Bay
L. Berryessa
Clear Lake
Boat or Sail . . .
Water Ski ....
Boat or Sail . . .
Water Ski ....
Boat or Sail . • •
Water Ski ....
Fish
1-4
9% .
2 .
* .
6 .
3 .
3 .
1 .
1 .
2 .
2 .
*
2 .
5-9
i 7
• * -L/o • •
. . 1 . .
. . 0 . .
. . 2 . .
. . 1 . .
* • -L * •
. . i . .
. . * . .
. . i . .
• » _L • •
. . * . .
. . i . .
10-19
. 1% .
. 1 .
. 0 .
. 1 .
. * .
. * .
. * .
. 1 .
. * .
. * .
. * .
. 1 .
20 or more
... 2%
... *
... 0
... 1
*
... *
... 0
... 0
*
... 1
... *
... 0
131
-------
Location Activity Number of Days
Other N.
Calif.
Outside
N. Calif.
Q. 7, 10,
Boat or Sail
Water Ski .
Fish ....
Boat or Sail
Swim ....
Water Ski
13, and 16 Pe
Activity
Boating or
Sailing . . .
Swimming . . .
Water . . .
Skiing
Fishing . . .
1
.
.
:rcent of
None
14%. .
(52%)**
26 . .
(87)
7 . .
(99)
18 . .
(65)
-4 5
9% ...
9 ...
2 ...
9 ...
2 ...
3 ...
1 . . .
activity
Per
1-24
. 2%. . .
( 7%)
. 1 . . .
( 3)
. 0 . . .
( 0)
. 1 . . .
( 5)
-9
2% . . .
-3 * • •
1 . . .
5 . . .
1 . . .
1 . . .
* . . .
in S. F
cent in
25-49
. 1%. .
( 4%)
. 1 . .
( 3)
*
( D
. 1 . .
( 5)
10-19 2(
2% ...
J • • *
*
4 ...
* ...
£- » » •
0 ...
. Bay
Bay
50-74
. . 2%. .
( 7%)
. . 1 . .
( 3)
. . 0 . .
( 0)
. . 1 . .
( 5)
) or more
. 1%
. 3
. 1
. 2
. 1
. 2
. 0
75-100
. . 8%
(30%)
. . 1
( 3)
. . 0
( 0)
. . 6
(20)
**Percentages of those engaging in activity.
Q. 7, 10, 13, 16, part d. Where do you usually on the Bay?
Activity Zone
Boat or Sail.
Water Ski . .
Fish ....
A
• • £/& • •
(12%)**
. . * . .
(11)
. . 0 . .
( 0)
. . 1 . .
( 9)
B
. 3% .
(18%)
1
(31)
. 0 .
( 0)
. 3 .
(27)
C
. . 7% .
(41%)
. . 2 .
' (44)
. . 0 .
( 0)
. . 4 .
(36)
D
. . 5%
(30%)
. . 1
(14)
. . 0
( 0)
. . 3
(27)
**Percentages of those using the Bay for the activity.
132
-------
Q. 7, 10, 13, and 16, parts e and f; 8, 11, 14, and 17, parts b, d, and
e. Reasons for curtailing or reducing recreation activity
in the Bay.
Activity & Reasons
Boating or Sailing
Bay Pollution
Other Bay Char.
All Other
Swimming
Bay Pollution
Other Bay Char.
All Other
Water Skiing
Bay Pollution
Other Bay Char.
All Other
.7%
3.0
9.8
7.5
12.8
10.3
1.4
3.6
2.9
Questopm
. 1%
.9
1.7
.3
.8
5
0
0
B
. 3%
.4
18.5
1.1
2.3
7.2
.1
.1
1.6
D
0 .5%
.4% 2.8
17.2 31.5
1.0 10.3
1.8 18.3
2.6 35.7
.5
.6
10.9
3.3
9.8
69.6
Total
1.6%
7.5
78.7
20.2
36.0
56.3
5.4
14.1
85.0
Fishing
Bay Pollution .4 .2 .4 .1 1.3 2.4
Other Bay Char. 3.3 .6 .4 .2 1.9 6.4
All Other 13.9 1.4 11.5 11.4 45.2 83.4
Q. 8, 11, 14, and 17, part a; 8, 11, 14, and 17, part c. Have you
ever been in S.F. Bay? Would you be interested in on the
Bay?
Activity
Boating or Sailing
Swimming
Water Skiing
Fishing
Q. 19 Do you personally engage in any of these other recreational
activities around the shoreline of the Bay?
Hiking 23%
Bird Watching 4
Picnicking 22
Wading 10
Sunbathing 13
Other 5
None of these 68
No answer *
"Have
Yes
20%
9
2
13
Been"
No
53%
61
91
60
"Interested
Yes
18%
5
12
12
in"
No
35%
56
80
48
133
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Q. 39 During a typical week, about how many hours do you spend on
outdoor recreation of any kind?
None 10%
Less than 1 hour 6
1 hour to 1.9 hours ... 8
2 hours to 3.9 hours ... 13
4 hours to 5.9 hours ... 13
6 hours to 7.9 hours ... 9
8 hours to 9.9 hours ... 12
10 hours to 14.9 hours. . . 13
15 hours to 19.9 hours. . . 6
20 or more hours 9
No answer 1
HEALTH ASPECTS OF SAN FRANCISCO BAY WATER QUALITY
Q. 18a Would you eat fish which were caught in the Bay?
Yes 72%
Qualified 12
No 16
Q. 18b If qualified or no to Q. 18a, why is that?
Safety aspects related to pollution .... 16%
Would eat only certain species 4
Don't like fish 6
Don't know, no answer 2
Q. 20a At the present time, do you feel that contact with Bay water
could be harmful to a person in any way?
Yes 27%
No 45
Don't know, not sure ... 27
No answer *
Q. 20b If yes to Q. 20a, in what way do you think it could be
harmful?
Causes skin rash or irritation 6%
Causes nausea/diarrhea 5
Makes you sick (not specific) 17
Other -1
Don't know, not sure 2
No answer -"•
134
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Q. 20c If yes to Q. 20a, how harmful do you think it could be?
Extremely harmful 9%
Somewhat harmful 11
Only slightly harmful 6
No answer 2
Q. 21a To the best of your knowledge, have you personally ever
become ill or suffered any harmful effects from Bay water?
Yes 1%
No 97
Don't know, not sure ... 1
No answer 1
0. 21b If yes to Q. 21a, in what way?
Skin rash or irritation 3%
Nausea-diarrhea 7
Makes you sick 0
Other 1
No answer 3
PERCEPTION OF AND RELATIONSHIP TO SAN FRANCISCO BAY
Q. 3 About how often do you see or look at any part of either San
Francisco Bay or San Pablo Bay?
Every day 24%
Two or three times a week 10
About once a week 10
2-3 times a month 12
About once a month 13
Less often than once a month 32
No answer *
Q. 25 How much do you personally care whether or not the Bay is
polluted?
A great deal 71%
Somewhat 19
Not very much 5
Hardly any 4
No answer 1
Q. 26a Do you think San Francisco Bay is polluted now?
Yes
No 18
Don't know, not sure 32
135
-------
Q. 26b If yes to Q. 26a, how polluted do you think it is?
Extremely polluted 12%
Somewhat polluted 27
Only slightly polluted 9
No answer 1
Q. 27a Do you remember seeing or hearing anything recently about
Bay pollution or Bay fill—either on TV, radio, or
newspapers, or somewhere else?
Yes 60%
No 40
CONFIDENCE IN SOCIETY AND TECHNOLOGY
Q. 26d Do you think that San Francisco Bay can be cleaned up?
Yes 42% (85%)**
No 2 ( 4 )
Don't know, not sure 6 (12 )
**Percentages of those who think Bay is polluted.
Q. 26f Do you think San Francisco Bay will be cleaned up?
Yes 25% (50%)**
No 11 (22 )
Don't know, not sure 14 (28 )
**Percentages of those who think Bay is polluted.
Q. 26e and 26g If not, why not?
Reason Can not Will not
Politics 1% 8%
Cost 1 7
Social factors 1 ^
Intransigent industry 1 3
Time ! 2
Technical factors 2 2
PUBLIC INFORMATION AND CREDIBILITY
Q. 22a Have you ever heard that San Francisco Bay is polluted?
Yes
No
Don't know, not sure
136
-------
Q. 22b If yes to Q. 22a, how long ago did you first hear this?
Within the past month ........ 3%
One-six months ago ......... 6
7 months-one year ago ........ 7
1.1-5 years ago ........... 28
5.1-10 years ago .......... 9
More than 10 years ago ....... 13
No answer .............. 1
Q. 22c If yes to Q. 22a, where did you first hear this?
Newspaper .............. 30%
Friend, relative .......... 20
TV program ............. 14
Radio ................ 9
Other ................ 6
Organization meeting ........ 2
Magazine, book ........... 2
Don't know, not sure ........ 5
No answer .............. 0
Q. 23 What do you think of when someone mentions pollution of
San Francisco Bay?
Causes
City, industrial, agricultural
wastes, sewage, filth,
detergents ............. 37%
Fill, garbage, debris, refuse,
trash, dumping ........... 32
Social and economic factors ..... 4
Effects
Physical and biological ....... 40
Esthetic ............... 26
Action orientation
Should determine cause, clean
it up, do something, etc ...... 11
Irrelevant responses ........... 1
Bay is not polluted ............ 2
All other ................. *
Don't know, no answer
137
-------
Q. 29 Overall, how much would you say you have seen or heard about
Bay pollution or Bay fill?
A great deal ............. 18%
Somewhat ............... 31
Not very much ............ 27
Hardly any .............. 24
No answer .............. 11
Q. 24 How do you think someone could tell whether the Bay were
polluted or not?
Debris, garbage, dead fish, oil, foam,
filth, low tide evidence ...... 56%
Dirty, murky, scummy water, color,
muddy, slimy, visual
appearance ............. 42
Odor ................. 27
Chemical, scientific analysis .... 27
Mosquitoes, fewer fish,
scavengers, oily fish, weedy
water, fewer crabs ......... 10
Seeing waste discharges from
boats, factories, etc ........ 2
All others .............. 1
Don ' t know , no answer ........ 7
Q. 26c What do you think causes San Francisco Bay to be polluted?
Industrial wastes and chemicals ...... 30% (60%)**
Garbage dumping/bay fill .......... 30 (59 )
City sewers ................ 25 (51 )
Boat Wastes ................ 12 (23 )
Agricultural run-off ............ 5 (10 )
People throw things in ........... 2 ( 4 )
Other ................... 2 ( 3 >
Don't know ................. 2 (3)
**Percentages of persons who think the Bay is polluted or are not
sure.
Q. 27b If yes to Q. 27a, what did you see or hear about the Bay?
Specific political process or debate .... 22% (37%)**
General political process or debate .... 18 (29 )
Bay pollution
General cause .............. 4 (6)
Specific cause ..............
General effect .............. 3 ( 6
Specific effect ............. 3 ( 6
138
-------
Bay fill
General cause * ( * )
Specific cause 3% ( 5%)
General effect 2 (4)
Specific effect 5 ( 8 )
Don't know, no answer, irrelevant
responses ..... 6 (10 )
**Percentages of persons who saw or heard something recently about
the Bay.
Q. 27c If yes to Q. 27a, if you wanted to find out more about this
issue, what would you do?
Specific sources
Local politician 11% (18%)**
Local agency 10 (17 )
State agency 8 (13 )
State or federal politician 5 (8)
Author or source of story 3 (5)
Federal agency 2 (4)
Friend or relative 1 (2)
Expert 1 (2)
All other specifics 3 (6)
General sources
Newspaper 6 (10 )
TV 3 ( 4 )
Magazine 2 (3)
Radio 1 ( 2 )
Library 3 ( 5 )
Organizational meeting 1 (2)
Conservation organization 3 (5)
Other organization 6 (11 )
All other general sources 2 (4)
Don't know, no answer 9 (15 )
**Percentages of those who had heard something recently about Bay
pollution or Bay fill.
Q. 30 Do you feel that you have received as much information about
Bay pollution or Bay fill as you would like to have?
Yes 39%
No 58
9
No answer e-
Q. 31 As you see it, whose responsibility is it to see that the
public gets information about the Bay?
Radio and TV 41%
Newspapers • 42
Magazines -*-4
139
-------
g.
Civic and conservation organ.
32 How much would you rely on:
Very Fairly
reli- reli- I'd be
able able cautious
Official state-
ments of
federal govern-
Statements by
independent
scientific
experts .... 40 . . . 35 ... 15 . .
Opinions of
your close
.c_,. _j_ •} 1 O 37
friends .... j ... J--5 ..._>/ . .
Newspaper
editorials and
*_.s-i_ in A "\ 7ft
articles .... lu ... «o . . . z.o . .
Official
statements of
state
government . . . jy . . . «*J. . . . J.J. . .
TV documen-
«.__.!,.„ OA 50 ... 16 . .
Statements by
private con-
servation
organiza-
....__ 01 40 ... 22 . .
Official state-
ments from
local govern-
ment 34 ... 40 ... 16 . .
. . . 40%
. . . 55
. . . 44
. . . 20
. . . 39
. . . 2
. . . 2
No
I'd be answer,
quite don't
skeptical know
. . 8% 4%
. 5 5
. . 39 8
.13 4
5 4
. . 6 4
. . 10 7
. . 5 4
140
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ATTITUDES TOWARD GOVERNMENT, ESTHETICS, AND TIME
Question 36
Strongly
Agree
Agree
Unde-
cided
Dis-
agree
Strongly
Disagree
No
Answer
One desirable feature of regional
government for the Bay Area is
that it keeps the solution of
problems close to home rather
than in Sacramento or
Washington 19%
A government agency should
decide how clean the water in
San Francisco Bay should be
rather than local citizen
groups 20
If a city feels that the State
has taken an unreasonable
position, the State should
be willing to compromise 17
A developer who wants to fill
part of the Bay is justified
because opposing government
agencies and conservationists
just have an extreme point
of view 3
The details of government
should be left to the
experts, so that the public
doesn't have to worry about
them 10
Events in the future are so
uncertain that we should only
be concerned with the
present 4
.. 46% ... 19% ... 9%
4% ... 2%
. . 33 ... 13 ... 26
. . 51 ... 18 ... 10
7 ... 2
2 ... 2
. . 6 ... 22 ... 39
28 ... 2
. . 18 ... 9 ... 40
. . 10 ... 7 ... 42
22 ... 2
36 ... 2
-------
Strongly Unde- Dis- Strongly No
Agree Agree elded agree Disagree Answer
7. It's all right to keep a
few redwood trees around
to look at but their most
important use is for
lumber 4% .... 9% .... 7% ... 36% 42% .... 2%
8. Technology is advancing so
rapidly that we shouldn't
worry about using up our
natural resources 2 .... 7 .... 8 ... 35 46 .... 2
9. It doesn't pay to plan ahead
more than a year or two these
days because the world is
changing so fast 5 .... 12 .... 7 ... 40 35 .... 2
10. You can say all you want
about beauty, but if no
one will buy it, it's
worthless 5 .... 13 .... 6 ... 36 37 .... 2
11. The Bay Area is a wonder-
ful place to live and
should stay just as it is .... 13 .... 24 .... 17 ... 35 7 .... 4
12. The world will probably be
destroyed within the next
20 years 2 .... 6 .... 15 ... 32 44 .... 2
13. Rather than waiting to find
the best method, pollution
control administrators should
take short-range action to
improve the condition of
the Bay 14 .... 42 .... 17 ... 18 6 .... 2
14. We should try to solve the
problems which are important
to us and let our children solve
theirs when their time comes . . 4 .... 14 .... 7 ... 41 31 .... 3
-------
be willing to
sacrifices now
r natural
Strongly
Agree Agree
. . . 35% .... 51% . .
Unde- Dis-
cided agree
. . 6% .... 3%. .
Strongly
Disagree
... 3% . .
Answer
. . 2%
15. We should
make some
to save ot
resources
16. Local city councils
usually aren't competent
to solve complex urban
problems 10 .... 31 .... 31 .... 22 3 .... 2
17. I would be willing to
donate one day a month
in the summer to help
clean up beaches 7 .... 22 .... 31 .... 24 11 .... 4
18. People who don't make
long-range plans are
going to regret it later
on 20 .... 48 .... 16 .... 12 3 .... 2
19. Our streams and lakes
should be clean whether
or not we use them 51 .... 42 .... 2 .... 2 2 .... 2
-------
APPENDIX C. DEMOGRAPHIC VALIDITY CHECKS
To check the accuracy of the sampling techniques, survey results
for several of the demographic variables were compared with data from
the 1960 Census for the San Jose Standard Metropolitan Statistical Area
(SMSA) and the San Francisco-Oakland SMSA (Census, 1962). The compari-
son is shown in Appendix Table C-l. These two combined SMSA's are not
identical with the study area covered by the survey but the differences
are not large.
Exact checks on validity from the 1960 Census are not possible
because population changes have taken place since that time. However,
in those cases where changes are most likely to have taken place, the
survey data probably differ in the right direction. E.g., the counties
that have grown since the 1960 Census were nearly all white in 1960.
If this ratio had continued, it would explain why the percentage of
Negroes is lower in the survey than in the Census. The difference for
other races is within limits of sampling error.
Larger differences are seen for educational level, with the survey
showing higher levels of education. This is consistent with recent
trends toward increasing levels of education. The same is true for
income. If the 1960 median income is adjusted to 1967 levels by an
index of the purchasing power of the dollar as measured by consumer
prices (World Almanac, 1968, p. 871), the comparison of medians is
$8520 for the survey and $8100 for the adjusted 1960 Census.
Age differences are all within limits of sampling error.
A larger discrepancy exists between the two sets of data for mari-
tal status, with lower percentages of single persons. No explanation
144
-------
APPENDIX TABLE C-l. DEMOGRAPHIC VALIDITY CHECKS
1960 Census
Survey
Survey Error
Limits
Ethnic Group
White
Negro
Other races
Education
Less than high school
Some high school
High school completed
Some college, business
or trade school
College graduate
Family Income
Less than $5,000
$5,000-$7,999
$8,000-$9,999
$10,000-$14,999
$15,000-$24,999
Greater than $24,999
Age
25-34
35-44
45-54
55-64
65 and over
Marital Status
Married
Separated, widowed,
or divorced
Single
Note—Error limits for survey are determined as follows:
Lower limit is the square root of pq/n.
Upper limit is the square root of 2pq/n.
89 . 3%
7.1
3.6
26.8
18.7
28.6
13.4
12.4
25.4
33.6
16.2
17.2
5.4
2.0
23.7
25.9
20.6
14.8
14.9
64.7
13.6
21.8
91.0%
4.3
5.1
11.6
14.6
30.6
25.9
17.3
22.4
23.5
15.8
25.2
12.1
1.1
23.9
22.6
21.3
14.3
17.8
72.6
15.7
11.6
±1.8-2.6%
1.3-1.8
1.4-2.1
2.1-2.9
2.3-3.2
3.0-4.2
2.8-4.0
2.4-3.5
2.7-3.8
2.7-3.9
2.4-3.3
2.8-4.0
2.1-3.0
0.6-1.1
2.8-3.9
2.7-3.8
2.6-3.7
2.3-3.2
2.5-3.5
2.9-4.1
2.3-3.4
2.1-2.9
145
-------
for this discrepancy is apparent.
Based on these comparisons, there appears to be no reason to
conclude that the survey is markedly non-representative of the Bay
Area population. The survey may even be more accurate than the Census
for 1967 conditions, though no such claim is made and it is quite
irrelevant to the evaluation of the survey results.
146
-------
APPENDIX D. STATISTICAL TECHNIQUES
KOLMOGOROV-SMIRNOV TEST
Chi-square is the usual test applied to contingency tables.
Expected table cell frequencies are taken as the row total times the
column total for the cell in question divided by the number of cases
in the table. Chi-square fails to provide a satisfactory test for
contingency tables when the expected cell frequencies in one or more
cells are too low. In dealing with nominal data, there may be no
objective satisfactory way to combine cells to produce a new table
that meets the usual chi-square requirements for contingency table
analysis (Walker and Lev, 1953, p. 107).
One technique for circumventing this problem is to eliminate rows
and columns that have low totals from the table (Funkhouser, 1967).
Thus, chi-square is applied to a sub-table of the full table. This is
a very useful heuristic technique. However, in some cases, even this
technique fails to provide a test and, of course, it would be desirable
to apply a test to all the rows and columns rather than to a subset.
Chi-square is basically a test of the equivalence of two frequency
distributions, i.e., do two populations have the same frequency distri-
butions? The Kolmogorov-Smirnov test, also a test of distribution
equivalence, might be expected to apply to contingency table analysis.
An empirical technique was developed to apply the test to such tables.
The population is taken as the total table. Cumulative distribu-
tion functions (cdfs) of this population are constructed by rank-
ordering row and column totals, smallest to largest. Thus, the cdf of
a row is constructed by re-ordering the cells in the row on the basis of
147
-------
column totals. The cdf for the row is the cumulative summation of
percentages beginning with the first re-ordered cell. The cdf of each
row is then compared with the cdf composed of re-ordered column totals.
The maximum difference between the cdf of a row and the cdf of the
column totals is tested as a Kolmogorov-Smirnov statistic (Tate and
Clelland, 1957, p. 131). N is taken as the row total. An identical
procedure is used for each column with re-ordering being done on the
basis of the row totals, and N is taken as the column total.
This procedure has a similarity to a procedure suggested by
Snedecor and Cochran (1967, pp. 250-251), though they do not suggest
the use of the Kolmogorov-Smirnov test. They say "When chi-square is
significant, the next step is to study the nature of the departure
from independence in more detail. Examination of the cells in which
the contribution to chi-square is greatest, taking note of the signs
of the deviations (f-F), furnishes clues, but these are hard to
interpret because the deviations in different cells are correlated.
Conputation of the percentage distribution of the row classification
within each column, followed by a scrutiny of the changes from column
to column, may be more informative. Further chi-square tests may help.
For instance, if the percentage distribution of the row classification
appears the same in two columns, a chi-square test may confirm this."
Their suggested comparison of row classification in two columns is
almost identical to the process described above, but with a different
test.
No explicit references are made in this thesis to the use of the
Kolmogorov-Smirnov test as a test of significance, because the chi-
148
-------
square test is used as the test of choice whenever it applies and there
was no instance of a final tabulation where chi-square did not apply.
The principal use of the K-S test was as a heuristic test in the
screening procedure that necessarily takes place in testing hypotheses
about relationships between variables.
It is noted that, in the above discussion, "test of significance"
refers to a test of the hypothesis that there is no relationship
between variables in the tabulation.
MULTIVARIATE TECHNIQUES
The technique of most value in the present study was multiple
discriminant analysis. It was used both as a screening technique, and,
in one instance, as a confirmation of the number of variables required
to optimally describe a relationship and the nature of the multivariate
relationship.
Multiple discriminant analysis is a technique for determining
linear functions of predictors that best discriminate between two or
more groups. For the two-group case, it is identical with multiple
regression analysis if the dependent variable is taken as having the
values 0 and 1, and these values are equivalent to a division of the
population into two groups (Rulon, 1951, p. 89). In all other cases,
multiple regression analysis differs from multiple discriminant
analysis.
An intuitive understanding of discriminant analysis can be
obtained by visualizing in n-dimensional space (n being the number of
predictor or independent variables) swarms of points, each swarm
149
-------
consisting of the points for one group. The location of the points is
determined from the computed discriminant functions. The functions are
such that the groups are maximally separated.
Cases not used in developing the discriminant functions can be
located in this n-dimensional space and classified into one group by
one of several decision rules. The one used in this analysis is that
of assigning a case to the group for which the probability of group
membership is highest (Dixon, 1967, pp. 214a-214u; Cooley and Lohnes,
1962, pp. 137-138). Other decision rules can be used; e.g., if one
wishes to be more certain of correctly classifying cases into one group,
at the risk of incorrectly assigning more cases of the other group,
such a rule can be formulated.
Discriminant analysis of survey research data enables the maximum
utilization of a powerful multivariate technique when the criterion or
dependent variable is a nominal or ordinal measure. If a case can
unambiguously be assigned to a group, discriminant analysis may be used
to calculate the functions that best distinguish between or among the
groups. If the dependent variable is an ordinal measure, there are
no problems with varying intervals between scale points.
150
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BIBLIOGRAPHY
1. Bay Conservation and Development Commission Staff, Recreation,
San Francisco Bay Conservation and Development Commission, San
Francisco, January, 1968, p. 9.
2. Bernard Berelson and Gary A. Steiner, Human Behavior (New York:
Harcourt, Brace and World, Inc., 1964), p. 88.
3. Alex Calhoun, John E. Skinner, Harold K. Chadwick, A.B. Albrecht,
and Cliffa Corson, Striped Bass Fishing Map for the Bay and Delta
Areas of Central California. The Resources Agency, Department of
Fish and Game, State of California, Sacramento, California, 1965.
4. U.S. Bureau of the Census, U.S. Censuses of Population and Housing:
I960. Census Tracts, Final Report PHC (1)-137, PHC (1)-138, U.S.
Government Printing Office, Washington, D.C., 1962.
5. William W. Cooley and Paul R. Lohnes, Multivariate Procedures for
the Behavioral Sciences (N.Y.: John Wiley and Sons, Inc., 1962),
pp. 35, 137-138.
6. W.J. Dixon, Biomedical Computer Programs (Los Angeles: Univ. of
California Press, 1967), pp. 214a-214u.
7. Gordon M. Fair, John C. Geyer, and Daniel A. Okun, Water and
Wastewater Engineering (New York: John Wiley and Sons, Inc.,
1966), p. 1-1.
8. Ray Funkhouser, Four-Way Cross-Tabulation Computer Program,
Unpublished, Stanford University, 1967.
9. Harold Gilliam, San Francisco Bay (Garden City, N.Y.: Doubleday
and Co., Inc., 1957), pp. 83-84.
151
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10. Bertram M. Gross, "The State of the Nation: Social Systems
Accounting", Social Indicators, edited by Raymond A. Bauer
(Cambridge, Massachusetts, The M.I.T. Press, 1966), pp. 166-167.
11. Oskar Morgenstern, The Accuracy of Economic Observations (Rev.
ed., Princeton, N.J.: Princeton University Press, 1963), pp.
242-282.
12. Outdoor Recreation Resources Review Commission, Outdoor Recreation
for America, A Report Submitted to the President and to the
Congress (Washington, D.C.: U.S. Government Printing Office,
1962), pp. 1-246.
13. Public Health Activities Committee, Sanitary Engineering Division,
"Coliform Standards for Recreational Waters", Journal of the
Sanitary Engineering Division. American Society of Civil Engineers,
v. 89, no. SA4, Proceedings Paper 3617, August, 1963, pp. 57-94.
14. P.J. Rulon, "Distinctions Between Discriminant and Regression
Analysis and a Geometric Interpretation of the Discriminant
Function", Harvard Educational Review, v. XXI (1951), pp. 80-90.
15. George W. Snedecor and William G. Cochran, Statistical Methods
(6th ed., Ames, Iowa, Iowa State Univ. Press, 1967), pp. 250-251.
16. State Water Quality Control Board, San Francisco Bay Regional
Water Quality Control Board, Water Quality Control Policy for
Tidal Waters Inland From the Golden Gate Within the San Francisco
Bav Region. The Resources Agency, State of California, Oakland,
1967.
152
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17. Philip N. Storrs, Robert E. Selleck, and Erman A. Pearson, A_
Comprehensive Study of San Francisco Bay, 1962-1963, Third Annual
Report, Sanitary Engineering Research Center, College of
Engineering and School of Public Health, Univ. of California,
Berkeley, SERL Report No. 64-3, April, 1964.
18. Merle W. Tate and Richard C. Clelland, Nonparametric and Shortcut
Statistics (Danville, 111.: Interstate Printers and Publishers,
Inc., 1957), p. 131.
19. Helen M. Walker and Joseph Lev, Statistical Inference (N.Y.:
Holt, Rinehart, and Winston, 1953), p. 107.
20. The World Almanac and Book of Facts, ed. Luman H. Long (1968
Centennial Edition, N.Y.: Newspaper Enterprise Association, Inc.,
1967), p. 871.
153
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