AN ANALYSIS OF THE FACTORS
LEADING TO THE USE OF LEADED GASOLINE
IN AUTOMOBILES REQUIRING
UNLEADED GASOLINE
EPA CONTRACT
68-01-3866 - Mod 1
September 29, 1978
SOBOTKA & COMPANY. !NC.
and
Market Facts Incorporated
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This report was furnished to the .Environmental Protection
Agency by Sobotka & Co., Inc. The opinions, findings, and
conclusions expressed are those of the authors and not nec-
essarily those of the Environmental Protection Agency.
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TABLE OF CONTENTS
Page
Number
EXECUTIVE SUMMARY 1
CHAPTER I - Introduction 3
A. Background and Objectives . . 3
B. Conduct of the Study 4
CHAPTER II - Outline and Summary of the
Principal Findings 5
CHAPTER III - Findings and Methodology 8
A. The Scope of Fuel Switching . 8
B. The Characteristics of
Switchers 12
C. Possible Causes of Fuel
Switching 14
1. Unavailability of
Unleaded Gasoline. ... 14
2. Price Level 15
3. The Un.leaded vs. Leaded
Price Differential . . 17
4. The Perceived Perfor-
mance of Gasoline. . . 18
5. Problems with Car
Performance in Relation
to the Use of Leaded
vs. Unleaded Gasoline. 20
D. Trade-Off Analysis 22
1. The Effect of Price
Differential 22
2. The Effect of Gasoline
Performance 25
3. The Impact of Premium
Unleaded Gasoline. . . 26
APPENDIX A - Detailed Tabulations (Separately bound)
APPENDIX B - The Questionnaires
APPENDIX C - The Trade-Off Method
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EXECUTIVE SUMMARY
In a survey of owners of automobiles requiring cataly-
tic converters 6% of the respondents reported that they use
leaded gasoline to fuel their vehicles; 77% reported that
they use only unleaded gasoline. Another 17% gave ambigu-
ous or inconsistent information about their fuel purchases.
The nature of their responses makes it appear possible or
even probable that they had used leaded fuel in their auto-
mobiles at least two times. Thus, it appears that at least
6% but no more than 23% of automobiles with catalytic con-
verters are operated with converters that may be inoperative
because two tankfuls of leaded gasoline may be sufficient to
render the converter inoperative.
If the price differential between leaded and unleaded
gasoline is eliminated, the percent of switching to leaded
for use in vehicles requiring unleaded will decline to about
6% from a current estimated level of roughly 15%."'' In order
to eliminate all switching without compulsion or inspection,
it would be necessary to improve people's perception of the
The 15% estimate is based on a survey separate from the
one whose results are described in the previous paragraph
and is consistent with those results. These estimates re-
flect use of leaded two or more times in vehicles requir-
ing unleaded. Estimates of about 10% based on service
station observation, appears lower. But not all switching
is consistent. Therefore, service station observations
understate the percent of vehicles requiring unleaded that
have been fueled with leaded two or more times.
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2.
quality of unleaded gasoline .because a significant fraction
of purchasers report that they believe that unleaded gasoline
leads to automobile performance inferior to that obtainable
with the use of leaded gasoline.
It is likely that switching will increase if current
price differentials and quality perceptions are maintained
because there is considerable dissatisfaction with the un-
leaded product among those who now use it consistently. The
introduction of premium unleaded grades is likely to cause a
small reduction in switching and may increase the use of un-
leaded gasoline in vehicles in which it is not required.
No investigation was made of the determinants of the use
of unleaded gasoline in automobiles without catalytic conver-
ters. Changes in gasoline qualities and prices would prob-
ably affect the demand for unleaded gasoline for use in these
vehicles.
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CHAPTER I
INTRODUCTION
A. Background and Objectives
This study was commissioned by the Environmental Pro-
tection Agency (EPA) in response to a concern over the
apparent widespread use of leaded gasoline in vehicles
requiring unleaded fuel. It has been estimated that as much
as 10 percent of the gasoline purchased for such vehicles is
leaded.^ Since two tankfuls of leaded gasoline used in a
car equipped with a catalytic converter will render the con-
verter inoperative, this fuel switching (the use of leaded
gasoline in a vehicle requiring unleaded) adds substantially
!
to air pollution.
The objectives of the study are to:
1. Determine the scope of and the casual factors
leading to the use of leaded gasoline in vehicles
designed for unleaded gasoline,
2. Analyze the importance of automobile users' per-
ceptions about price differentials, absolute
price levels and other key variables contributing
to switching, and
3. Estimate the extent to which switching might be
reduced by changes in gasoline price differentials
or other measures.
EPA estimate. Note that more than 10% of vehicles requir-
ing unleaded fuel are likely to have been fueled with leadec
gasoline two or more times even though some do not use
leaded consistently.
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1.
B. Conduct of the Study
The results presented in this report are based on a
mail survey conducted through the facilities of Market
Facts' Consumer Mail Panels. This facility consists of
some 65,000 households broadly representative of the con-
tinental United States population who have agreed to
participate in mail surveys from time to time.
The survey reported here was restricted to households
known to have post-1974 vehicles in family use. Of 2,600
questionnaires mailed out, 1,500 were returned and 1,266^
were analyzed. An additional mailing was made to a differ-
ent sample of comparable households in order to obtain an
independent estimate of switching by use of a "Sensitive
Question" technique.^
The analysis was restricted to vehicles known to
require a catalytic converter. Hence none of the study's
results are directly usable for inferences about the use
of unleaded gasoline in vehicles not equipped with catalytic
converters.
Pick-ups, vans, and recreational vehicles were excluded
because of difficulties in ascertaining the catalytic
converter requirement.
2a mailing was made to 1000 households asking for information
about the most recent model year automobile in the household.
Responses were received from about 800 households of which
307 reporeted about a post-197** automobile which required a
catalytic converter.
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5.
CHAPTER II
OUTLINE AND SUMMARY OF THE FINDINGS
A. The Scope of Fuel Switching
This section is a description of the methods used to
estimate the extent of fuel switching and to define
switchers (6%) , non-switchers (77%) and possible switchers
(17%) .
It is estimated that about 15% of the post-1974 car
owners are now using or have used leaded gasoline in cars
that require unleaded gasoline.
B. Characteristics of Fuel Switchers
This section shows the variation of switching with
respect to such variables as:
1. Geographic location,
2. Degree of urbanization,
3. Demographics — age, education and income,
4. Car purchase and use, and
5. Fuel purchase conditions such as attendant vs.
self-service, and cash vs. credit card use.
Switching is found to be more prevalent in the Pacific
region than in the East, in rural than in metropolitan areas
and among the younger, middle income, better educated segmen
of the population who are most .likely to be economy consciou
sophisticated buyers.
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o.
C. Some Possible Causes of Switching
This section explores the following factors as pos-
sible causes of switching:
1. Possible unavailability of unleaded gasoline,
2. Price level and unleaded-leaded price differ-
ential,
3. Gasoline performance, and
4. Perceived car problems.
Possible unavailability" of unleaded gasoline is found
to be a negligible factor in switching. These findings do
show sufficient discontent with the performance of unleaded
gasoline to identify this as a probable cause of some
switching. Price differentials between unleaded and leaded
are identified as a probable cause of switchings
D. Trade-Off Analysis
This section uses market simulations based on the Trad
Off Analysis method to study the probable effect on switch!
of:
1. Varying unleaded-leaded gasoline price differ-
entials ,
2. Improving the gasoline buyers' perceptions of
the performance of unleaded gasoline, and
3. Introducing a premium grade unleaded gasoline
with varying price configurations.
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The results suggest that eliminating the price
differential and improving the quality, or consumers'
perceptions of the quality/ of unleaded gasoline should
greatly reduce, and almost completely eliminate, fuel
switching. The introduction of an unleaded premium
would cause only a slight direct reduction in switching
given a small price differential between unleaded and
leaded regular grades. However, there does appear to
be considerable interest in such a product among current
users of unleaded gasoline. This suggests that it may
stem further growth in switching in the long run by
providing a more satisfactory alternative to unleaded
regular.
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8.
CHAPTER III
FINDINGS AND METHODOLOGY
A. The Scope of Fuel Switching
In this section we estimate the extent of fuel switch-
ing. We also describe the method used to classify respon-
dents according to the likelihood of their having used two
or more tankfuls of leaded gasoline in their post-1974 cars.
The classification is based on their responses to questions
about their last and previous gasoline purchases for those
cars.
The principal obstacles to estimating the extent of
fuel switching and to identifying those who have switched
are:
1. Reluctance to admit to fuel switching on the part
of those respondents who may feel that it is
socially undesirable and possibly illegal, and
2. Confusion about the distinction between leaded
and unleaded gasoline and about grades, and
types of gasoline generally purchased.
To circumvent the first of these obstacles, reluctance
to admit switching, Market Facts mailed a brief question-
naire to a sample of car owning households (independent of
the one used in the buying survey) with cars requiring
catalytic converters. This questionnaire employed a
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9.
"Sensitive Question" technique that enabled the respondent
to supply information useful in estimating the extent of
fuel switching without revealing whether the respondent
had actually switched fuels.
The essential portion of the questionnaire used for
this purpose follows:
Step one — Remove the coin attached to this
questionnaire and flip it —
Step two — If the coin comes up
Heads — Answer Question #1 only
Tails — Answer Question #2 only
but do not indicate which question
you are answering.
1. Was your mother born in the month
of April? RECORD ANSWER IN THE
APPROPRIATE BOX TO THE RIGHT.
2. I have used leaded gasoline in this
car two or more times since I have
been driving it. RECORD ANSWER IN
THE APPROPRIATE BOX TO THE RIGHT.
ANSWER
BOX
Yes
No ~
Based on the responses to this question, it was esti-
mated that 13.7% of the post-1974 car owning panel house-
holds are fuel switchers.^"
^"The formula for calculating the "yes" responses to the
"sensitive" question is
h s + h M = Y
where S is the percent answering "yes" to the sensitive
question, M is the percent of females born in April (8.3%)
and Y is the total percent answering "yes" in the box (11%)
The' lower and upper 90% confidence limits for the.13.7?
estimate are 5-9% and 21.5%
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10.
The classification of respondents according to the
likelihood of their having switched fuels was based on
the following information about the last gasoline purchase
for their post-1974 car:
1. Responses to direct questions as to whether
they purchased unleaded or leaded gasoline,
and
2. Responses to two other questions which might or
might not be consistent with their response to
the direct question: what grade they bought
(open-ended response) and the relative price
of the gasoline they bought (whether it was the
lowest or highest price/ a price in between, or
the only gasoline available at the station).
On the basis of this information, respondents were
classified according to their reported last purchase of
gasoline as follows:
Reported
Leaded
Unleaded
TOTAL
_6%
£4%
Definite
5
77
Probable
1
4
Doubtful
-
11
Inconsistent
*
2
*Less than 0.5%.
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11.
Previous purchases (other than the most recent) were
also studied. The respondents who reported buying un-
leaded were asked whether they had ever bought leaded
gasoline and, if so, the relative frequency of their use
of leaded and unleaded. Those who reported a purchase
of leaded gasoline the last time they bought gasoline
were asked similar questions about previous purchases
of unleaded.
On the basis of their last and their previous pur-
chases , respondents were classified as follows:
For most of the analysis of the findings, we make
comparisons among three groups:
Switchers (definite)
Probable switchers
Possible switchers
Non-switchers (definite)
6%
4
13
77
100%
Switchers (definite)
Probable and possible
6%
switchers
Non-switchers
77
100%
17
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B. The Characteristics of Switchers
This section describes the characteristics of
switchers. The principal findings are displayed in
the table on the following page and further details
are shown in Appendix A.
As might be expected, fuel switching is more
prevalent in rural areas where there are likely to
be more "do-it-yourselfers" who find it easy to modify
the tank openings.
Fuel switching is by no means restricted to
lower income groups. It is more prevalent among rela-
tively young, middle income, educated people who are
more sophisticated buyers than the poor, and are more
price conscious than the very affluent.
Since self-serve avoids the involvement of an
attendant as an accomplice in fuel switching, it is
not surprising that switching is more prevalent among
self-serve gasoline buyers.
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13.
Characteristics of Switchers
Compared to the average, switching is:
Higher In;
The Pacific coast region (120)
Rural areas
(120A)
Lower In:
The East
Metropolitan areas
Higher Among;
25-44 year olds (127)
Middle income groups
($17.5-$24.9K) (125)
College graduates (121)
Males1 (121)
Used car buyers ( 4)
Those with cars driven
15-49.9K miles ( 4A)
Self serve buyers ( 20)
Cash buyers ( 21)
Lower Among;
45 + year olds
Low and very high income
groups ($25K and up)
High school graduates or
less educated
Females
New car buyers
Those with cars driven
less than 15K miles
Attendant serve buyers
Oil company credit card
buyers
Notes:
1) There were no definite switchers in New Jersey,
where state law provides for an annual inspec-
tion of emissions. (119)
2) Definite switchers have more cars per household
than do other groups. (1)
^Definite switchers only.
( ) Numbers in parentheses refer to page number in
Appendix A.
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14.
C. Possible Causes of Fuel Switching
In this section, we explore the findings of the survey
with a view to isolating the possible causes of fuel switch-
ing. In particular, we examine the relation between fuel
switchers and each of these factors:
1. Unavailability of unleaded gasoline,
2. Price level,
3. The unleaded vs. leaded price differential,
4. The perceived performance of gasoline,
5. Problems with car performance in relation to
use -pf leaded vs. unleaded gasoline.
While the results are not conclusive, they do point
to two factors as the principal causes of switching: the
price differential between unleaded and leaded gasoline,
and a perception of unleaded gasoline as inferior in
performance.
1. Unavailability of Unleaded Gasoline
Very few respondents (6%) reported that the reg-
ular grade of unleaded gasoline was unavailable at the
station where they last bought gasoline. One may safely
rule out unavailability as a significant factor in fuel
switching except, possibly, for some occasional purchases
in an emergency situation.
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15.
The following table shows responses used in
evaluating this factor:
Percent of Respondents
^Reporting Grade and Type:
Not No
Available Available Answer
Grade and Type
Regular unleaded 6% 82% 12%
Premium unleaded"'" 39 32 29
Regular leaded 3 77 20
Premium leaded 14 57 29
Number of respondents (1,266)
2. Price Level
The impact of price level was examined in two
ways:
a. In terms of the reported price of regular
leaded gasoline at the station where the
respondent made his/her last gasoline
purchase, and
In view of the fact that very few brands currently sell a
premium unleaded gasoline we might have expected many more
than 39% of the respondents to report its unavailability
at the station. This finding suggests that some respondents
may think that some (or perhaps all) brands of unleaded
gasoline are of "premium" grade, possibly because of its
price differential over regular leaded.
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16.
b. In terms of the perceived base price.
This was defined to respondents as:
"The price per gallon of the least expen-
sive grade of gasoline that might be
available in your area at a station
carrying a brand that you would con-
sider using."
The results of both of these analyses are incon-
clusive in establishing a causal relation between fuel
switching and price level. Fuel switchers and non-switchers
report no significant difference in the average perceived
price of leaded regular gasoline at the station where they
made their last gasoline purchase as illustrated below:
Definite and
Probable Non-
Switchers Switchers
Mean reported price
of leaded regular
in*cents per gallon
(cpg) 60.6 cpg 60.5 cpg
The following table shows that fuel switching
may be slightly more prevalent in areas where gasoline
prices are low than where they are high:^"
This finding that switchers are more prevalent in areas
of perceived low regular leaded prices may reflect the
greater use of self-service (at a lower price) by switchers
than by non-switchers.
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17.
Base Price (cpg')
Percent Switching
(Includes Probable
Switchers)
No answer
56
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18.
4. The Perceived Performance of Gasoline
Respondents were asked which of the four grades
and types of gasoline would give the best and which would
give the worst performance in their car. The following
table shows how many of them rated each of the grades and
types best for the group as a whole and for each of the
switcher groups. Note that, except for the switchers,
more than four out of five rated one of the unleaded
grades best. As might be expected, nine out of ten
switchers rated leaded grades best.
Percent Rating Type and Grade Best
Type and Possible Non-
Grade Total Switchers Switchers Switchers
Unleaded 82%. 7% 88% 87%
Regular 44 4 55 46
Premium 38 3 33 41
Leaded 11 % 86% _5% 6%
Regular 5 53 3 2
Premium 6 33 2 4
No answer 7% 7% 7% 7%
Number of
respondents (1,266) (72) (217) (977)
The following table shows how many of the respon-
dents rated each of the four types and grades of gasoline
poorest in performance. Note that one out of four respondents
was reluctant to single out any one type and grade as poorest.
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19.
Another one out of four rated one of the unleaded grades
(predominantly the regular grade) as poorest. In the
switcher group, two out of three singled out an unleaded
grade as poorest. Even among the non-switchers, who use
only unleaded gasoline, one out of five rated an unleaded
grade as poorest. These results point to dissatisfaction
with performance as a probable cause of past switching and
a possible cause of more switching in the future.
Percent Naming Types and Grade as Poorest
Type and
Possible
Non-
Grade
Total
Switchers.
Switchers
Switch i
Unleaded
23%
62%
22%
20%
Regular
20
51
19
18
Premium
3
11
3
2
Leaded
53%
16%
51%
56%
Regular
47
10
44
51
Premium
6
6
7
5
No answer
24%
22%
26%
24%
Number of
respondents
(1,266)
(72)
(217)
(977)
The preceding analysis suggests that fuel switch-
ing could be reduced by:
a. Improving the performance^" of unleaded gaso-
line, and consumers' perceptions of its performance
b. Introducing a premium unleaded gasoline.
"*"The term "performance" was not further .defined for the respon-
dents. As we shall see later, it is likely that different
respondents used different criteria of gasoline performance.
One may safely assume, however, that rating a grade or type
of gasoline as likely to give the poorest performance is a
valid indication of the perceived quality of the product.
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20.
Both of these possibilities are analyzed in relation to
price differentials in Section D of this report.
5. Problems With Car Performance in Relation to The
Use of Leaded Vs. Unleaded Gasoline
In order to explore which aspects of gasoline per-
formance might be causally related to switching, comparisons
were made as to the relative incidence of specific problems
between switchers and non-switchers. While the results do
not definitively pin-point any specific car problems as a
cause of switching, they are consistent with the belief that
the lower octane rating of unleaded gasoline is a source of
dissatisfaction among its users.
Consistent users of unleaded gasoline (non-switchers)
are more likely than leaded gasoline users (switchers) to have
problems with knocking and "hesitation," lag in expected
power when accelerating or going uphill, as illustrated
in the following table:
Percent Reporting
Problem
Non-
Car Problem Encountered Switchers Switchers
Knocking
Had any problem
Had a severe problem
27%
27
7
33
33
3
30%
30
7
Hesitation
Had any problem
Had a severe problem
39
39
8
Number of respondents (72)
(977)
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21.
On the other hand, leaded gasoline users are more
likely to have encountered problems with run-on (or
dieseling) and rough idling. The data is shown below:
Percent Reporting
Problem
Non-
Car Problems Encountered Switchers Switchers
Run-On
Had any problems 38% 30%
Had a severe problem 9 6
Rough Idling
Had any problem 44 31
Had.a severe problem 5 4
Number of respondents (72) (977)
There were no appreciable differences between:.switchers
and non-switchers with respect to the reported incidence or
degree of severity of problems with stalling, hard starting,
or lack of pep.
An important aspect of car performance for most car
owners is mileage, the number of miles per gallon. Here,
the leaded gasoline users seem to have a definite advantage.
Switchers report getting an average of 2.1 miles per gallon
more than consistent users of unleaded gasoline. Again, a
table illustrates the data:
Average Miles Non-
per Gallon Switchers Switchers
City driving 18.0 mpg 15.2 mpg
Highway driving 21.6 mpg 19.6 mpg
Overall 19.3 mpg 17.2 mpg
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22.
The better mileage reported by the switchers may be
a function of the cars they own or of their driving habits
rather than of the gasoline they use.
D. Trade-Off Analysis
1. The Effect of Price Differential
In the previous section of this report we ex-
plored gasoline buyers' previous buying behavior and
perceptions in order to find clues as to the probable
causes of fuel switching. In this section, we use the
method of Trade-Off Analysis^" to predict how buyers would
respond to various product offerings, such as, premium
and regular grades of unleaded and leaded gasoline at
various price differentials.
The data used in this analysis was obtained by
asking respondents to choose one of two products in each
of 38 product pairs in which the products differ with
respect to two attributes (for example, type/grade and
price), but are assumed to be identical in all other
respects. From these 38 choices, one can infer how a
buyer would choose one gasoline among a bundle of gasoline
products that may differ with respect to:
a. Type and grade,
b. Price,
c. Self-service vs. attendant service, and
d. Method of payment: cash only vs. credit
or cash
"'"See Appendix C for a description of the method.
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23.
The products are assumed to be identical in all
other respects. These inferences make it possible to
simulate various situations where the gasoline buyer
would have to choose among several grades and types of
gasoline each at its own price (or price differential)
but assumed to be the same in all other respects. In a
typical application, we consider a scenario such as:
Product One - Regular leaded gasoline at
the base price^"
Product Two - Regular unleaded gasoline at
2 cents per gallon (cpg) above
the base price
Product Three - Premium leaded gasoline at
6 cpg above the base price
The Trade-Off model predicts the fraction of
buyers who would choose each product. We might then,
for example, consider several scenarios where the price
differential of Product Two is changed, all other variables
remaining fixed, in order to explore the effect of a price
change on the preference for leaded over unleaded gasoline,
that is, on the percent who might .switch.
This has been defined as: "The price per gallon of the
least expensive-grade of gasoline that might be available
in your area at a station carrying a brand that you would
consider using."
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Before discussing the results of several such
sets of simulations, it should be kept in mind that they
would be applicable only to gasoline bought for a car
required by EPA regulations to use only unleaded fuel.
Moreover, respondents have been alerted to keep in mind
that "... to use leaded gas in your car might require
changes in the tank opening to accommodate the wider
nozzle used at pumps that have leaded gas."
The following table shows the results of varying
the price differential of unleaded regular gasoline from
0 to 8 cents per gallon above the base price (by 2 cpg
intervals) in a market where the buyer has to choose
among these products: (1) leaded at the base price,
(2) unleaded regular at 0, 2, 4, 6, 8 cpg above base,
(3) leaded premium at 6C above base.
Unleaded Price Percent
Differential Choosing
(cpg above base) Leaded
OC 6%
2
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25.
A further increase to 8 cpg would increase
switching to the point where more than two-thirds of
the gasoline purchased for cars requiring unleaded would
be leaded. Note that while a reduction in the price
differential would reduce the amount of switching, one
could not expect it to be completely eliminated even
if the differential were to be reduced to zero.
2. The Effect of Gasoline Performance
The existence of a hard core of switching that
would remain even at a zero price differential should
not be surprising in light of earlier findings that show
substantial dissatisfaction with the performance of un-
leaded gasoline among switchers and considerable discontent
with its performance among non-switchers.
In order to explore the impact of performance
we repeat the same price simulations among those who
rated the performance of unleaded regular gasoline as
the best of the four types.;and grades considered.
The results of the simulations displayed in the
following table indicate that among this group, the amount
of switching is somewhat reduced at current and higher
price differentials and reduced to 2 percent at the zero
differential — ojie-third of that for the population as
a whole.
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26.
Among Those
Unleaded Price
Differential
(cpg above base)
Among All Rating
Buyers Unleaded
Requiring Best In
Unleaded Performance
OC
2$
4C
6C
8$
11
15
31
56
6%
22
66
2%
4
7
The appearance of 2 percent (or indeed of any)
switching at price parity between leaded and unleaded
gasoline among those who consider unleaded gasoline to
be superior in performance may' seem paradoxical since one
would expect everybody to choose the better of two products
at the same price. However, one should bear in mind that
the phrase "best performance" may not have exactly the
same meaning for all people. For example, some people may
think that unleaded gasoline delivers more power than
leaded but that it has a deleterious effect on the engine;
others may not consider "best performance" to include better
mileage.
3. The Impact of Premium Unleaded Gasoline
est in a premium unleaded gasoline and at least one major
oil company has announced the forthcoming introduction of
such a product. The following simulations of a market with
four products — two leaded and two unleaded grades —
The findings of the study suggest a strong inter-
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27.
indicate that the introduction of unleaded premium would
have some but not a substantial impact at the lower price
differential levels (unleaded regular vs. leaded regular)
that were examined. They might have a substantial impact
in reducing switching at higher price differential levels.
The conditions of the simulation are:
a. Regular leaded at base price; premium
leaded at base + 6 cpg.
b. The unleaded grades at the seven price
differential levels shown in the following
table:
Unleaded price
Differentials
(cpg above base)
Regular Premium
OC
0$
2C
2$
4C
4$
6«
2$
4£
4«
6 $
6C
8$
8$
Percent Choosing
Leaded Gasoline
With . With No
Premium Premium
Unleaded Unleaded
Available Available
5%
5
8
9
11
12
14
6%
6
11
11
15
15
31
Note that at the current average 4 cpg differential
between leaded regular and unleaded regular, the introduction
of an unleaded premium at 4 cpg above unleaded regular would
reduce switching from 15% to 12%. If the differential between
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28.
premium and regular unleaded is reduced to 2 cpg, the switch-
ing rate is not affected very much. It is reduced by only
one percentage point
Unleaded Price.
Differential
(cpg above base)
Regular Premium
Percent Choosing Each Type/Grade
Leaded
Unleaded
Regular Premium Regular Premium
oc
2C
5%
. *%
67%
28%
0
-------
APPENDIX B
THE QUESTIONNAIRES
-------
CONSUMER MAIL PANELS
12S SOUTH MANKUN ITRITT • CHICACQ, IUJMOU 6000ft
(9309)
I
Dear Panel Member,
Today I would like your help In & study about gasoline. I've been asked to find out how people decide
what gasoline to use in their cars. To determine which member of your household should Answer my
questions please answer questions A, B and C. Record the "qualified household member's" relation-
ship LnQu. C. If you are that person continue answering the remaining questions. If another member
is the "qualified household member, please ask that person to begin with the Introduction before
Question D below.
Cordially,
-7
A. How marry cars are there in your household? Please include any passenger car, station wagon,
ran, or pink-up that is maintained by anyone in your household and available for personal or
family use by one or more family members.
.Number of Cars In Your Household: _____ (13)
B, I am interested in finding out about recent model year cars, 1975, 1976, 1977 and 1978. If
there Is more than one men car In your household, this questionnaire Is to be filled out for the
most recent model year car. For example, if your household had a 1976 model year car and
a 1977 model year car, you would choose the 1977 model year car. If there is more than one
car of the most recent model year, for example, two 1977 model year cars, please choose
the one that is used the most often.
On the line below, for the most recent model year car, please write in the make, series, model
year, body style, number of cylinders and number of miles the car has been driven.
Number of Miles
Number of Car Has Been
_Make Series Yea£ Bodj_Stvle .C^llnders^ __Drivei^___
Example: (Ford) (Granada) (1977) (2 door Sedan) (6) (12,500)
14 16 111 I Il8 191 I 120 ,1"'
C. The person who la most likely to bay the gasoline for the car yea described in Question B is:
(21)
(22-27)
Male Head of Household* • • . • 0
Female Head of Household • • • O
Other Male ~
Other Female
(28)
Please have the person who Is most likely to boy the gasoline for the car you described in
Question B £U1 out the rest of this questionnaire*
-------
Page 2
(9309)
To the "qualified household member":
I us liking you to tell me about your gasoline purchases only as they apply to the particular car,
pickup or too described in Question B. As you answer please consider your gasoline purchases
for only that vehicle even Ii you are also the principal gasoline purchaser for other household vehicles.
Tour help on this survey Is very important and, of-course, I appreciate it very much.
O, Was the car described In Question B bought new, used, or is it leased?
New Ql
Used 02 (29)
Leased 03
Other (specify) D
E. How long have you been using this car?
6 months or less Ql ....
More than 6 months 02
F. About how m»ny miles per1 gallon do yon generally get with this car? (Please round your
estimate to the nearest whole number.)
In city 1 I ImPG (31-32)
On highway 1 1 ImPG (33-34)
Over-all, on the average . I I IMPG (35-36)
G. About how frequently do you buy gasoline for this car?
Two or more times a week Ql
Once a week 02
Once every ten days 03
Twice a month 04 (37)
Once a month 05
Less than once a month. 06
Question* 1-6 are about the last time you bought gasoline for this car — the one
described In Question B, Throughout the questionnaire 1 will be talking about
unleaded and leaded gas. In your part of the country unleaded gas may be called
"lead-free" or "no lead". Leaded gas is gasoline containing lead.
1. About how long ago did you last buy gasoline for this car?
Within the past 2 or 3 days. Ql
4-7 days ago 02
1-2 weeks ago 03 (38)
More than Z weeks but within the past month. 04
More than one month ago 05
2a. What type of service did you get at the station?
Self-service 01
Attendant service 02
3a. What brand of gasoline did you buy at that time?
3b. What grade of gasoline did you bay at that time ?
43
(39)
2b. How did you pay for your pochase?
Cash Ql
Oil company credit card 02 (40)
Bank or other credit card .... 03
411 I I4i
I44
-------
(9309)
Pag© 3
3c. Most gat stations sell only 2 or 3 grades of gasoline. When you bought gasoline the last time,
did you buy:
The lowest price gasoline at the station. . . . 01
The highest price gasoline at the station • . • [J2
The gasoline at a price In between (ii (^5)
the station had 3 grades) 03
3d* And what was the cost per gallon ot the gasoline you bought? (Please round to the nearest cent)
m t per gallon (46-47)
3a. Wti the ga«ollne you got at that time unleaded (that U, no lead or load-free) or was It gasoline
containing lead (that Is, leaded)?
Unleaded (no lead or lead-free). . .
PLEASE ANSWER THESE QUESTIONS IF YOU
BOUGHT UNLEADED (NO LEAD OR LEAD-FREE)
GASOLINE LAST TIME.
4a. Have you ever bought leaded gasoline for
thU car?
Yes . . . 01
No.... 02 -
(49)
-(SKIP TO QU. 6a)
4b. Why did you bay leaded gas? (Please "X"
only one box.)
Only type available at station . . Pll
Costs less *. 02
Performs better 03
Recommended by ear
manufacturer 04
Other (Please describe) (50)
4c. Which type of gasoline do you buy most
frequently for this car 7
Unleaded Dl
Leaded O? (51)
Both equally . 03
Contained lead (leaded). • . Q2
~7
(48)
PLEASE ANSWER THESE QUESTIONS £F YOU
BOUGHT LEADED GASOLINE (i.e., CONTAINING
LEAD) LAST TIME.
5a. Have you ever bought unleaded gasoline for
this car?
(")
No .... 02 (SKIP TO QU. 6a)
5b. Why did you buy unleaded gas? (Please "X"
only one box.)
Only type available at station . . 01
Costs less I~j2
Performs better I 13
Recommended by car
manufacturer 04
Other (Please describe) (53)
Sc. Which type of gasoline do you buy most
frequently for this car?
Unleaded Dl
Leaded 02 (54)
Both equally (03
6a. Of the grades and types of gas listed below, which do you think would give the best performance
for your car? ("X" one box in Column A.)
6b. Of the grades and types of gas listed below, which would give the poorest performance for your
car? ("X" one box in Column B.)
6c. Below are listed some grades and types of gasoline that may be available in your area -• only two
or three of these are likely to be available at any one gas station. In Column C, please "X" either
the "Yes" or the "No" box to indicate whether or not you think that the grade and type waa available
at the station where you last bought gasoline for this car.
6d. In Column D, please write in your best recollection of the price per gallon of each grade and type
that was available at that station. (Please give me the pimp price Including taxes to the nearest
cent.)
ABC D
Best
Performance
Poorest
Performance
Available
At
Station?
No Yes
Pump Price
t Per Gallon
Regular leaded. ...
. Di
Di
~1
02
—+-
1 1 If/iaL
(57-59)
Regular unleaded . .
. 02
O2
~1
02
f 1 U / iaL
(60-62)
Premium leaded. . .
. 03
~3
~1
a.
1 1 U/eal.
(63-65)
Premium unleaded .
1=14 <55)
04 (56)
~1
~2
—»¦
f [ |i/aal.
(66-68)
6e. At most stations, regular leaded gasoline Is the lowest priced grade and type of gasoline at the
station. Even If you can't recall the prices of all the grades and types of gasoline at the station
of your last purchase, how(much more do you think you would have to pay for regular unleaded
than for the leaded gas at that statLon?
f per gallon more for unleaded gas than for leaded gas (69-70)
(71-78 open) 7qfoT71fiQ
-------
Page 4
Questions 7 and 8 are about problems jrou might have Had with this car and what,
If anything, you did about them.
(9309)
Card 2
(Dup. 1-12)
?a.
7b.
Below Is a list of problems that a person driving a car over a period of time might notice.
Next to each of these problems, please "X"' the appropriate box Ln Column A to indicate
whether or not you've cvar had that problem with this car.
For each problem you've had with this car, please "X" the box in Column B that best describes
bow severe this problem was.
A B
Ever Had
Problem How Severe?
Problems A Car Might Have No Yes Slight Severe
Hard starting 01 02 >¦ 01 02 (13-14)
Rough Idle 01 02 i^0l 02 (15-16)
Stalling 01 02 1^01 02 (17-18)
Hesitation (lag ln expected power 01 02 » 01 02 (19-20)
when accelerating or going uphill) 01 02 ~ 01 02 (21-22)
Knock or ping when accelerating
or going uphill 01 02 ¦ i» 01 02 (23-24)
Engine run-on — engine continues to run
after Ignition la turned off 01 02 01 02 (25-26)
Poor mileage 01 02 ^"01 02 (27-28)
Engine lacks pep 01 02 ^01 02 (29-30)
Other engine problems (Describe) 3J | jj2
Dl 02 *-01 02 (33-34)
8a.
8b.
9».
9b.
LOOK UP AT QU. 7a. IF YOU HAVE MARKED A "NO" FOR EVERY PROBLEM
LISTED ABOVE SKIP TO QU. 10a.
Of all the problem* you have had as described in Qu, 7a, think about the most recent one. Have you
ever had any work done to correct that problem? Please do not count routine things such as oil
changes or kibei. Do count anything Involving an adjustment or part change whether done by you
ox a mechanic.
Yes . . . 01
No .... 02 (SKIP TO QU. 9»)
(35)
To what extent was the problem corrected?
Not at all 01
Somewhat 02 (36)
Completely 03
Have you ever changed the brand, type, or grade of gas Ln order to correct a problem with thi^
car?
Yes
No.
.01
.02 (SKIP TO QU. 10a)
(37)
The last time you changed brand, grade or type of gas, to what extent was the problem corrected
as a result of this change?
Not at all Ol
Somewhat 02 (38)
Completely 03
10a. Since you've been driving tkis car, have you ever bean advised or Influenced by any person or any-
thing you saw or heard to change the brand, type, or grade of gasoline you use in the car?
.~l
Yes . ,
No.... 02 (SKIP TO QU. 11a)
(39)
10b. What brand, type or gradn were you advised to switch to?
BRAND
(Please specify name
on the line below)
10c. Who gave you that advice?
GRADE AND TYPE
4dl I Ul
Loaded
Regular
~i
Unleaded
Regular
~2
Leaded
Premium
03
Uoleaded
Premium
~4
Other
~s
Hew ear dealer
... m
Garage mechanic. , . .
...02
Service station . . . « .
...03
Friend or relative . , .
... n4
Advertising.
...05
Other (Describe)
• ~
(42)
(43)
(44 open)
-------
(9309)
Page 5
11a. Since you've been driving this car, when was the last time, If ever, you switched the brand,
grade or type oi gasoline you put in it?
Never Cjl—»-(SKIF TO QU. 12)
More than 6 months ago , . 02
Past six months 03
lie.
(45)
lib. What reason or reasons made you switch brand, grade or type of gasoline?
46
47
48
49
Aav others?
50
51
52
53
Please think of the last time you switched the brand, type, or grade of gasoline you were using
in this car. On the lines below, write in the brand and check the type and grade of gasoline you
were using in this car before switching, and write in the brand and check the type and grade you
are now using. (Please Ignore any listed grades or types which may not be available In your
area.)
GRADE AND TYPE
Brand Name
Before Switching:
Leaded Unleaded Leaded Unleaded
Regular jlejular_ Premium Premium Other
Brand Name
After Switching:
~l
~l
~2
~2
~3
~3
~4
04
5J I ^5
05 (56)
57! I ks
~5 (59)
The next section of this questionnaire deals with some of the factors that go Into
your decisions as to what gasoline to buy and where to buy it. In particular, I'm
interested in your choice of the grade of gasoline, the brand, the type of service at
the station, and the method of payment you prefer (cash or credit card), and the
pries. Please remember that in your part of the country unleaded gas may be
called "lead-free" or "no lead". Leaded gas Is gasoline containing lead.
12. Below is a list of six types and grades of gasoline that might be available to you at service stations
in your area -- although any one station is not likely to have more than two or three of these grades
today. The premium grade generally has a higher octane rating than regular. Some brands carry
a grade that is intermediate between the usual regular and premium grades. Whether you've had
any experience with all the grades or not, I'd like to know what grades you think you would prefer
tojut_inj2H2L£2Z ^ they were all equally available to you all other things being equal -- In other
words, if all six grades were available at the same price, in the same brand, etc.
I would like you to rank each of the six grades of gasoline in the order of your preference. As you
are ranking them, please keep in mind that to use leaded gas in your car might require changes in
the tank opening to accommodate the wider nozzle used at pumps that have leaded gas.
Now, In Column 12 below, please put a "1" In the box next to the grade you would prefer to put in
your car if you could choose from all six grades. Then put a "2" in the box next to the grade that
would be your second choice if you could not have your first choice. Please continue until you have
shown your preference for each of the six grades. When you are done, there will be a number from
1 to 6 In each box to show your rink order of preference for each of the six grades. Please do not
give me any ties (for example, do not put a "3" In two different boxes to show your 3rd rank order
preference) or leave any boxes blank.
Col. 12
Rank Order of Preference
(1 * most preferred to
Grade^f_Ga^ollne> 6 = least •preferred)
Regular leaded ~ (60)
Regular unleaded ~ (61)
Intermediate leaded . . ; . ~ (62)
Intermediate unleaded. . ... ~ (63)
Premium leaded ~ (64)
Premium unleaded ~ (65)
-------
P»ge 6 (9309)
Next, I'd like to know your preference for hrpe of service and method of payment. (Price, brand
and grade being equal.
13a. Would you prefer attendant service or self-service?
Attendant service 01
Self-service 02 '
13b. Would you prefer to buy gasoline at a station that accepts cash only or accepts either cash or a
credit card?
Accepts cash only 01
Accepts either a credit card or cash .... 02 '
14. In considering the price of various options such as brand, grade, gasoline type, service type and
payment method I'll ask you to compare the price with a base price. This it the price per gailon
of the least expensive grade of gasoline that might be available In your area at a station carrying
a brand you would consider using. Generally, in most places, the least expensive grade Is
regular leaded. This varies from one area to another and even from one station to another in
the same area. Which of the prices below do you think is closest to the base price in your area °-
that is, the price per gallon of the least expensive grade of gasoline that you can buy in your area
at a station that carries a brand you would consider using.
50f per gallon , . 01
54f per gallon . . 02
56f per gallon . . 03
59f per gallon , . 04
fcl£ per gallon . . 05
64f per gallon . . 06
67t per gallon . . 07
70£ per gallon . . 08
(68)
(69-78 open)
79(32] 80
15. In order to get a better idea of your preferences for different gasoline choices, I'm going Co ask
you about various combinations of factors such as brand, price, grade, type of gasoline, type of
service and payment method.
Listed below are several pairings that will give you a choice between two different factors, but
are similar to each other In all other respects.
Please read both factors carefully and decide which you would prefer. If you prefer the factor on
the left the most, then please draw a circle around the "L" next to that factor; but U you prefer
the factor on the right the most, then draw your circle around the "R" next to that factor.
EXAMPLE
You Pay Zf Above
You Pay The Base Price The Base Price
& L OR R k
Attendant Service Self-Service
Self-Service Attendant Service
ic L OR R
-------
(9309)
Page 7
The following pairings are aHko_ln_aJl_r^oDect3_ except for the two factors below:
GRADE AND TYPE OF CAS
ic
TYPE OF SERVICE
Please circle either "L" or "R" to Indicate your preference for the pairs below.
Card_3
Dud.
1-12
Intermediate Leaded Gas
ic
Attendant Service
(13)
L OR R
Regular Leaded Caa
4c
Self-Service
Self-Service
It
Intermediate Unleaded Gas
(14)
L OR R
Attendant Service
ic
Premium tTM*-adf>d Gas
Self-Service
b
Premium Leaded Gas
(15)
L OR R
Attendant Service
&
Regular Leaded Gas
Premium Leaded Gas
It
Attendant Service
(16)
L OR R
Premium Unleaded Gas
Ic
Self-Service
The following pairings are alLke tn all respects except for the two factors below:
GRADE AND TYPE OF GAS
ic
METHOD OF PAYMENT
Please circle either "L" or "R" to Indicate your preference for the pairs below.
Intermediate Leaded Gas
ic
Station Accepts Cash Only
(17)
L OR R
Regular Leaded Gas
Ic
Statlos. Accepts Credit
Card Or Cash
Station Accepts Credit
Card Or Cash
Regular Unleaded Gas
Station Accepts Credit
Card Or Cash.
Intermediate Unlaaded Gas
(18)
L OR R
(19)
L OR R
Station Accepts Cash Only
ic
Regular Leaded Gas
Station Accepts Cash Only,
k
Regular Unleaded Gas
Premium Unleaded Gas
ic
Station Accepts Cash Only
(20)
L OR R
Premium Leaded Gas
ic
Station Accepts Credit
Card Or Cash
Intermediate Unleaded Gas
ic
Station Accepts Cash Only
(21)
L OR R
Premium Unleaded Gas
(c
Station Accepts Credit
Card Or Cash
-------
Page 8
(9309)
The following pairings Are alike In all respects except for the two factors below:
PRICE
U
TYPE OF SERVICE
Please circle either "L" or "R" to Indicate your preference for the pairs below.
You Pay The Base Price
k
Self-Service
(22)
L OR R
You Pay 4{ Above
The Base Price
Attendant Service
Attendant Service
ic
You Pay if Above
The Bate Price
(23)
L OR R
Self-Service
!c
You Pay bf Above
The Base Price
The following pairings are alike in all respects except for the two factors below:
PRICE
It
METHOD OF PAYMENT
Please circle either "L" or "R" to Indicate your preference for the pairs below.
You Pay The Base Price
ic
Station Accepts Cash Only
(24)
L OR R
You Pay 2$ Above
The Base Price
Station Accepts Credit
Card Or Cash
You Pay The Base Price
Ic
Station Accepts Cash Only
Station Accepts Credit
Card Or Cash
You Pay Above
The Bate Price
(25)
L OR R
(26)
L OR R
You Pay 6f Above
The Base Price
Station Accepts Credit
Card Or Cash
Station Accepts Cash Only
b
You Pay 4£ Above
The Base Price
-------
(9309)
Pago 9
The following pairings are alike in all respects except for the two factors below:
GRADE AND TYPE OF GAS
it
PRICE
Please circle either "L" or "R" to indicate your preference for the pairs below.
Intermediate Unleaded Gas
Ic
You Pay Above
The Base Price
(27)
L OR R
Premium Leaded Gas
k
You Pay 6£ Above
The Base Price
You Pay 6£ Above
The Base Price
Premium Unleaded Gas
(28)
L OR R
You Pay 8£ Above
The Base Price
Premium Leaded Gas
You Pay 2f Abcve
The Base Price
(29)
L OR R
You Pay The Base Price
ic
Premium Unleaded Gas
Intermediate Unleaded Gas
Regular Unleaded Gas
(c
You Pay Above
The Base Price
(30)
L OR R
Intermediate Leaded Gas
ic
You Pay The Base Price
Regular Unleaded Gas
&
You Pay 8£ Above
The Base Price
(31)
L OR R
Regular Leaded Gas
ic
You Pay 4£ Above
The Base Price
You Pay 8f Above
The Base Price
Premium Leaded Gas
(32)
L OR R
You Pay 4C Above
The Base Price
Intermediate Leaded Gas
You Pay 2( Above
The Base Price
Premium Unleaded Gas
(33)
L OR R
You Pay 6 ^ Above
The Base Price
Premium Leaded Gas
Intermediate Unleaded Gas
Ic
You Pay 8C Above
The Base Price
(34)
L OR R
Regular Unleaded Gas
ic
You Pay b<; Above
The Base Price
-------
Page 10
(9309)
The following pairings are alike in all except for the two factors below:
GRADE AND TYPE OF CAS
ic
PRICE
Please circle either "L" or "R" to Indicate your preference for the pairs below.
Regular Leaded Gas
(35)
Intermediate Leaded Gas
<>
L
OR
R
ic
You Pay 4( Above
The Base Price
You Pay 2f Above
The Base Price
You Pay 4f Above
The Base Price
(36)
You Pay 8f Above
The Base Price
&
L
OR
R
ic
Regular Unleaded Gas
Regular Leaded Gas
You Pay Above
The Base Price
(37)
You Pay Above
The Base Price
ic
L
OR
R
ic
Intermediate Unleaded Gas
Intermediate Leaded Gas
Premium Unleaded Gas
(38)
Premium Leaded Gas
it
L
OR
R
-------
(9309)
Page 11
The following pairings are alike in all re«T>eets except for the two factors below:
GRADE AND TYPE OF GAS
U
PRICE
Please circle either "L" or "R" to Indicate tout preference for the pairs below.
Regular Unleaded Gas
(43)
Regular Leaded Gas
ic
L
OR
R
tc
You Pay 2f Above
The Bate Price
You Pay The Base Price
You Pay The Bale Price
(44)
You Pay 2£ Above
The Base Price
tc
L
OR
R
ic
Regular Unleaded Gas
Regular Leaded Gas
You Pay The Base Price
(45)
You Pay 2$ Above
The Base Price
Ic
L
OR
R
tc
Intermediate Leaded Gas
Prnmlum Unleaded Gas
Regular Unleaded Gas
(46)
Intermediate Unleaded Gas
Ic
L
OR
R
tc
You Pay The Base Price
You Pay 2$ Above
The Base Price
Intermediate Leaded Gas
(47)
Premium Leaded Gas
tc
L
OR
R
tc
You Pay The Base Price
You Pay 4$ Above
The Base Price
You Pay The Base Price
(48)
You Pay 2£ Above
The Base Price
Ic
L
OR
R
Ic
Premium Unlaaded Gas
Premium Leaded Gas
You Pay Above
The Base Price
(49)
You Pay 4( Above
The Base Price
tc
L
OR
R
tc
Intermediate Unleaded Gas
Premium Unleaded Gas
Intermediate Unleaded Gas
(50)
Intermediate Leaded Gas
Ic
L
OR
R
tc
You Pay M Above
The Base Price
You Pay 2£ Above
The Base Price
(51-78 open)
79 EDO 80
-------
CONSUMER MAIL PANELS
321 SOUTH FRANKLIN STREET • CHICAGO. ILLINOIS 60606
(9324)
CM
A
PLEASE READ THE QUESTIONNAIRE BEFORE DETACHING THE COIN.
I
)ear Panel Member,
this questionnaire is about the most recent model year car, station wagon, van or pick-up that is
naintained by anyone in your household and is available for personal or family use by one or more
amily members. If there is more than one recent car of the same year, choose the one that is used
nost often.
q the line below, for the most recent model year car, please fill in the make, series, model year,
>dy style, number of cylinders and number of miles the car has been driven.
Number of
Model Number of Miles Car Has
Make SerieB Year Body 5tyle Cylinders Been Driven
xample: (Ford) (Granada) (1977) (2 door Sedan) (6) (12,500)
The person who is most likely to buy the gasoline for the car described above is:
Male Head of Household I ll
Female Head of Household 02
Other Male Q3
Other Female I 14
Please have the person who is most likely to buy the gasoline for this car fill out the rest of this
questionnaire.
As far as you know does the manufacturer of the vehicle described above specify that only unleaded
j(that is, lead-free or no lead) gasoline.be used in that vehicle?
Yes . . . 01 No . . . 02 Don't know . . . 03 (15)
No matter how you answered Question 2, please continue following these instructions. It's
important that everybody cooperates. In this study, I'm Interested in finding out how many people
are actually using leaded gasoline (that is, gasoline that contains lead) even though their care
may require only ua leaded (that is, lead-free or no lead) gasoline be used. However, I have
found that many people are reluctant to tell me whether they do this or not. You can help us get
this information without revealing what you yourself do by following the instructions on the other
side.
-------
Page 2
(9224)
3. There are two questions below with provisions for only one answer. You are to decide which ques-
tion to answer by flipping a coin. If the coin comes up heads you should answer the first queBtior?
by "X"ing the appropriate box. If it comes up tails, you should ignore the first question and use
the answer box -- Yes or No -- to answer the second question. Only you will know whether the
answer you have given applies to Question HI or Question #2.
If you follow these instructions exactly, I will never know which of the two questions you answered
or whether you yourself use leaded gasoline in your car. But by combining your answers with
those of other people, I will be able to figure out statistically how many people in the population
have used leaded gasoline -- provided you have followed the instructions exactly. Remember --
Step one -- Remove the coin attached to this questionnaire and flip it --
Step two — If the coin comes up
Heads - Answer Question #1 only
Tails - Answer Question #2 only
but do not indicate which question you are answering.
1. Was your mother born in the month of April? RECORD ANSWER IN
THE APPROPRIATE BOX TO THE RIGHT.
2. I have used leaded gasoline in this car two or more times since I have -
been driving it. RECORD ANSWER IN THE APPROPRIATE BOX TO
THE RIGHT.
ANSWER
BOX
Yes ~
No ~
Please return the questionnaire as promptly as possible. The dime is yours for taking the few minutes
to complete these questions.
Cordially,
-------
APPENDIX C
THE METHOD OF TRADE-OFF ANALYSIS
-------
44
THE METHOD OF TRADE - OFF ANALYSIS
The method of Trade-off Analysis is designed to predict a
consumer',3 preference among a bundle of products all of which have
the same attributes to varying degrees or levels. In this study we
consider consumer choices among gasoline purchases all defined in
terms of the four attributes underlined below.
Grade and Type
of Gasoline
Regular Leaded
Price Differential
over the Base Price
(CPG)
Regular Unleaded
Intermediate Leaded
Intermediate Unleaded
Premimum Leaded
Premium Unleaded
0
2
4
6'
8
Type of
Service
Self-
serve
Atten-
dant
serve
Method
of
Payment
Cash
Cash or
Credit
For example, we may wish to predict how a consumer would choose
among:
Purchase One - A regular grade of leaded gasoline at the base
price with self-serve at a station accepting hi's
credit card
Purchase Two - A regular grade of unleaded gasoline at 2 cpg
above the base price at a credit card station with
attendant service
Purchase Tnree-A premium grade of leaded gasoline at (cpg)
above the base price at a credit card, station with
attendant service
Trade-off analysis makes it possible to predict his choice from
any combination of the 120 (6x5x2x2) products (combinations of attribute
levels) that can be configured from the attribute-level list displayed.
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^5
The three components of this method are: (1) a technique of
data collection requiring a respondent t'o consider "trade-offs" among
desirable alternatives: (2) a computational method which derives
"utilities" accounting as nearly as possible for each respondent's
choice behavior; and (3) a simple market simulation model which attempts
to determine those characteristics of a product which will maximize
its share of preference within any particular competitive context.
The trade-off questioning technique ia demonstrated in pages
7-11 of the survey questionnaire (see Appendix B.). The computational
methods that may be used to derive the "utilities" are described in
some detail in the accompanying articles. This method consists of
first deriving "part-utilities" for each attribute level (for each
respondent). The "utility" of any product ( combination of attribute
levels) is computed by multiplying the "part-utilities" associated
with each of the attribute levels making up the product.
The part-utilities are determined by the requirement that they
predict as closely as possible the 38 pair-wis.e choices expressed by
the respondent. That is, if a respondent has expressed a preference
for the left hand combination; of attributes below over the right hand
one , the product axb should be greater than the product cxd (where
a,b,c,d are the part-utilities as shown below):
The 38 conditions of this kind imposed by the respondent';^
choices are sufficient to determine the 16 "part-utilities" (one for
each attribute level) that describe the respondent'^ preference system.
Given any set of products (attribute level combinations), the respondent
should choose the product with the greatest "utility" as computed by
Leaded regular (a)
at base price (b)
L or R
Unleaded regular (c)
at6cpg over base (d)
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M6
multiplying the "part-utilities" of the attribute levels associated
with each product.
An example of how this method would be applied to predict a
particular respondents' choice among the three purchases described
above is illustrated below. This respondent would
choose Purchase One, since its "utility" (83) is greater than either of
the competitors' (23 or 17).
The simulation method used in this study consists of computing
the number of respondents choosing each of the several products making
up the "market".
PREDICTING INDIVIDUAL CHOICE
Purchase Purchase Purchase
#1 #2 #3
Beg. Reg. Prom
Leaded Unleaded Leaded
9 Base 9 Base + 2C f Base +
Crade/Type Part-Utllltles
Regular Traded 100 100
Regular Unleaded 48 48
Mid Leaded 90
Kid Unleaded 47
Proniun Leaded 97 97
Pi-cnim Unleaded 47
Price Differential
(CFG)
0 100 100
2 48 48
4 28
6 18 18
8 8
Service Type
Self 83
Attendant 100
Payment Type
Cash or Credit 100
Cash only 58
83
100 100
ICO 100 100
UTILITIES
83
33
17
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