Frequently Asked Questions
Click on the question text for answers to the following frequently asked questions:
The Scientists and Engineers Statistical Data System (SESTAT) is a database containing information about
a representative sample of persons in the United States who are working or trained as scientists or
engineers. SESTAT, sponsored by the National Science Foundation, comprises data from three sources:
the National Survey of College Graduates, the National Survey of Recent College Graduates, and the
Survey of Doctorate Recipients.
The SESTAT data system comprises three surveys sponsored by the National Science Foundation, each
contributing a distinct segment of the target population. The 1993 National Survey of College
Graduates (NSCG), conducted by the Bureau of the Census, contributes persons who had obtained a
Bachelor's degree or higher as of April 1, 1990 and who were either working as a scientist or engineer
during the week of April 15, 1993 or who received a Bachelor's, Masters's, or foreign Doctorate degree
in science or engineering before April 1, 1990. The 1993 National Survey of Recent College Graduates
(NSRCG), conducted by Westat, Inc., contributes persons who received a Bachelor's or Master's degree
in a science or engineering field in the United States between April 1, 1990 and June 30, 1992. The 1993
Survey of Doctorate Recipients (SDR), conducted by the National Research Council, contributes persons
who received a Doctorate degree in a science or engineering field in the United States between January
1, 1942 and June 30, 1992.
SESTAT defines scientists and engineers as those who either received a college degree (Bachelor's level
or higher) in a science or engineering field or who work as a scientist or engineer.
The following types of degree fields are considered to be science or engineering: computer and
information sciences; mathematical sciences; agricultural and food sciences; biological sciences;
environmental life sciences (including forestry sciences); chemistry; earth science, geology &
oceanography; physics and astronomy; other physical sciences; economics; political science and related
sciences; psychology; sociology and anthropology; other social sciences; engineering (all types). It should
be noted that the following are not considered to be science or engineering: actuarial science; business &
managerial economics; computer programming; data processing technology; computer, mathematics,
science, or social science teacher education; electrical and electronics technologies; industrial production
technologies; mechanical and other engineering-related technologies; social work.
The following types of occupations are considered to be scientists and engineers: computer and information
scientists; mathematical scientists; agricultural and food scientists; biological and life scientists; forestry
and conservation scientists; chemists; atmospheric and space scientists; geologists (including earth
scientists); oceanographers; astronomers; physicists; other physical and related scientists; economists;
political scientists; psychologists; anthropologists; sociologists; science and technology historians; other
social scientists; engineers (all types). In addition, postsecondary teachers of any of these fields are
considered to be scientists or engineers by occupation. It should be noted that the following are not
considered to be scientists or engineers: top- and mid-level managers of scientists and engineers; health
occupations; secondary teachers of any subject; technologists/technicians in the biological/life,
mathematical, or physical sciences; computer programmers; engineering technologists/technicians;
actuaries.
Each of the three surveys that make up the SESTAT data system collects new data every two years. The
data on this public use file were collected in 1993.
The database contains information about the respondent's employment status during the week of April 15,
1993 (including a coded occupational field); past employment; other work-related information (such as
years of professional work experience and attendance at meetings, conferences, workshops, and seminars).
With respect to education, information on up to three college degrees is available (including coded degree
fields); recent courses taken; and demographic data are also collected. In addition, variables related to the
sample design as well as analysis weights can be found on the file. Each record has a variable indicating
from which of the three surveys the observation came.
There are 273,564 observations on the SESTAT database: 214,643 from the National Survey of College
Graduates; 19,426 from the National Survey of Recent College Graduates; and 39,495 from the Survey
of Doctorate Recipients.
While the SESTAT data system captures the vast majority of the scientists and engineers in the United
States, there are some small segments of the target population that are not captured: persons who obtained
their first college degree in science or engineering between June 30, 1992 and April 15, 1993 (the
reference week); persons with their first science or engineering degrees obtained abroad since April 1,
1990, but living in the U.S. during the reference week; persons working as a scientist or engineer during
the reference week, but who received their first college degree (in a non-science non-engineering field)
between April 1, 1990 and the reference week; persons who were living outside the U.S. on April 1, 1990
(immigrants who later arrived or Americans who returned from abroad) and did not receive a science or
engineering degree in the U.S. between their arrival and June 30, 1992, but who are part of the SESTAT
target population.
The SESTAT sample targets all scientists and engineers living in the U.S. during the reference week,
regardless of the place of birth. Foreign-trained scientists and engineers whose first science or engineering
degree at the Bachelor's level or higher was obtained abroad after April 1, 1990 are not represented in the
sample if they had no Bachelor's degree in any field prior to April 1,1990 or were not working as a
scientist or engineer during the reference week. Furthermore, those who received their first Bachelor's
degree in any field abroad after April 1, 1990 but who are working as a scientist or engineer during the
reference week are not represented.
As long as the person received a Bachelor's degree or higher in a science or engineering field, he or she
will be represented in the SESTAT database, regardless of current occupation. Furthermore, a person who
is currently working as a scientist or engineer, but who has never received a Bachelor's degree or higher
in science or engineering, is also included in the SESTAT target population.
The National Science Foundation sponsors the three surveys that the SESTAT data system comprises, but
each is carried out by a separate organization. The National Survey of College Graduates is conducted by
the Bureau of the Census. The National Survey of Recent College Graduates is conducted by Westat, Inc.
The Survey of Doctorate Recipients is conducted by the National Research Council.
The 1993 National Survey of College Graduates was conducted by mail with computer-assisted telephone
interviewing (CATI) follow-up of all nonrespondents. Nonrespondents to the CATI follow-up were
followed up via computer-assisted personal interviewing (CAPI). The 1993 National Survey of Recent
College Graduates was conducted almost entirely via CATI, with some mail follow-up for sample
members who could not be reached by telephone. The 1993 Survey of Doctorate Recipients was
conducted by mail with CATI follow-up of all nonrespondents.
There are three analysis weights supplied on the SESTAT database. In almost all circumstances, one
would use the weight labeled "Z_WEIGHTING_FACTOR." This weight has been adjusted for multiplicity
issues associated with the fact that the three surveys have been combined into one database. Because of
the differential rates at which respondents were sampled, both within and across surveys, it is essential that
analysis weights be used when producing estimates. Use Z_WEIGHTING_FACTOR to obtain estimates
for the national population of scientists and engineers.
For special purposes, one may want to use data from only one of the three component surveys, in which
case "Z_WEIGHTING_FACTOR_SURVEY" should be used. Z_WEIGHTING_FACTOR_SURVEY is the
survey-specific weight and has not been adjusted for multiplicity issues. To look at the results from a
specific component survey, use Z_SURVEY_IDENTIFIER to identify the component survey and
Z_WEIGHTING_FACTOR_SURVEY to obtain estimates. For the NSCG, use data with
Z_SURVEY_IDENTIFIER = 1; for the SDR, use data with Z_SURVEY_IDENTIFIER= 2; and for the
NSRCG, use data with Z_SURVEY_IDENTIFIER = 3.
A third weight variable, Z_WEIGHTING_FACTOR_LONGITUDINAL is reserved for future use.
When analyzing SESTAT data for national population estimates, use the weight variable labeled Z_WEIGHTING_FACTOR to determine which data records to include in your unweighted counts. Z_WEIGHTING_FACTOR is set to zero for those data re
cords that should be excluded from any national population analyses. Therefore, you should include only those records with non-zero weights (Z_WEIGHTING_FACTOR <> 0), even when you are developing unweighted estimates.
Use the variable Z_SURVEY_IDENTIFIER when preparing unweighted estimates for the SESTAT component surveys. For the NSCG, use data with
Z_SURVEY_IDENTIFIER = 1; for the SDR, use data with Z_SURVEY_IDENTIFIER= 2; and for the NSRCG, use data with Z_SURVEY_IDENTIFIER = 3.
The WEB pages in the SESTAT system utilize HTML 3.2 extensions. Any browser
that supports HTML 3.2 should operate properly. The pages have been tested
extensively with Netscape Navigator 3.0 and Microsoft Internet Explorer
3 with no known browser-related problems. Many users report that setting
the default font to Arial 10 point (Netscape) or font size "Small" (Explorer)
results in an acceptable appearance for the pages. Please contact the
Webmaster if you experience any difficulties with your browser or with the
suggested settings.
The arrival of "WEB" friendly spreadsheet software makes it easy to convert SESTAT table output
into a spreadsheet. Since the tables generated by SESTAT are "html" files, any application
that reads an "html" file can read a SESTAT table. Simply save your SESTAT table as a separate
file on your computer and then "open" it with your application. Instructions are presented below:
Excel 97 (and later versions of Excel) can read "html" files and automatically convert them to a
spreadsheet:
Once SESTAT generates a table, save it on your computer by selecting "File", then "Save As"
from your WWW browser menu. Specify the desired file name and location and click "Save".
Load Excel 97 and click on "File", then "Open" and click on the SESTAT HTML output file
you just saved. The HTML file will be automatically converted into a EXCEL spreadsheet which
may be manipulated and saved as with any other spreadsheet.
Warning: SESTAT automatically divides large tables into subtables or pages, each roughly 80
columns by 60 lines in size. This means that tables with more than a few columns or rows (or
both) will be subdivided and presented as a series of several smaller subtables with separate row
and column headings for each subtable. You should be aware that each subtable within your
SESTAT HTML output file will be converted as a separate group of cells within your
spreadsheet. A substantial amount of manual cutting and pasting may be required to remove
duplicate column and row headers and to reorganize your spreadsheet so that all the data rows
and data columns are contiguous.
Updated: February 25, 1998