&EPA
United States
Environmental
Protection Agency
Office of Research
and Development
Washington, DC 20460
EPAA620/R-01/004f
July 2002
EMAP-West Communications
Data Analysis Workshops Transfer Statistical Technology
to Regions, States, and Tribes
One of the main goals of EMAP-West is to develop, test, and
transfer the technology behind the Program's monitoring design
and data analysis to the cooperating states and tribes in EPA
Regions 8, 9, and 10. This process is well underway for the
Coastal component because 1999 data from the sampling of the
estuaries of Washington, Oregon, and California are now ready for
analysis. All three states will be conducting their own analyses of
their data in cooperation with EPA scientists.
While the underlying sample survey design and data analysis are
complex, a series of workshops accompanied with the appropriate
documentation has simplified the process to make it more accessi-
ble to cooperating state personnel. The tools necessary to complete
the analysis process are now available to the three coastal states
and the analysis process has begun.
The workshops, jointly presented by the Western and Gulf Ecology
Divisions, describe the EMAP probabilistic approach to estimating
the condition of an ecological resource. The first part of a
workshop reviews the steps necessary to create a data base that is
ready for analysis. Included are:
• A review of the process of creating survey sampling designs
for coastal waters.
• The requirements for information management including
data organization and accessibility.
• Quality assurance and quality control procedures and their
importance in producing a report of condition that is scientif-
ically defensible.
Since the overall objective of the Coastal Component is to provide a
statement of the status of the west coast estuaries, a complete and
well-documented data set is required. Once the data set is complete,
the analysis process can begin. The primary output of these analy-
ses are cumulative distribution functions (CDF) (see figure below).
100
72% of the area of the
population of estuaries
measured has an index
score of 20 or less.
We are 95% confident
that the true value is
between 59% and 90%
The CDF enables the reader to estimate the cumulative total area
(or proportion) of a resource with an indicator of condition less
than some specified value (e.g., a state water quality standard).
The survey design ensures that these estimates are made with a
quantifiable degree of certainty.
To aid client organizations in building the internal capacity to
analyze EMAP coastal assessment data, EMAP-West scientists
have produced a series of "How To" technical manuals tailored to
the specific assessment designs of individual state participants.
(See example title page below.)
ANALYSIS OF EMAP COASTAL
WESTERN PILOT DATA:
Description of Analysis Flow Paths
Using SAS Routines
Version 1.0 -Oregon
August 9, 2001
Walter Nelson
Pacific Coastal Ecology Branch
Western Ecology Division
Newport, Oregon
Virginia Engle
Coastal Ecology Branch
Gulf Ecology Division
Gulf Breeze, Florida
nda Harwell
Coastal Ecology Branch
Gulf Ecology Division
Gulf Breeze, Florida
National Health and Environmental Effects Laboratory, U.S. EPA
These manuals provide detailed instructions on how to process
EMAP data thus easing the learning curve for new participants.
The current manuals provide the statistical program routines that
allow complex analyses to be conducted routinely using commer-
cially available software packages. Individualized, hands-on train-
ing sessions are also conducted with state participants to insure
their ability to effectively use a variety of analysis tools.
The initiation of the technology transfer initiative by EMAP
Coastal has received very positive feedback from participating
state organizations. The resulting data reports serve as the founda-
tion for subsequent assessments of coastal condition jointly
conducted by EPA and state personnel. Having the internal
capability to develop and analyze EMAP data will make the state
and tribal cooperators much more independent as they continue
future status and trend monitoring.
10 20 30 40
Hypothetical Index Score
For further information, contact:
Walt Nelson
Coastal Lead
Nelson.Walter@epa.gov
(541)754-4041
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