Frequently Asked Questions

Click on the question text for answers to the following frequently asked questions:


What is SESTAT?

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.

How many surveys are in the SESTAT data system and how do their samples fit together?

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.

Who is included in the definition of "scientist" and "engineer" for SESTAT?

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.

How often are the SESTAT data updated?

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.

What kind of information can be found on the SESTAT data system?

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.

How many observations are on the database?

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.

Who is not represented in the sample?

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.

Do your data include foreign-born and foreign-trained scientists and engineers living in the U.S.?

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.

What about people trained in a science or engineering field but currently working in another field?

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.

Who collects the SESTAT data?

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.

How were the data collected?

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.

Which analysis weight should I use when analyzing SESTAT data?

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.

How do I obtain the correct UNWEIGHTED counts?

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.

Do I need to use special settings for my Web browser?

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.

How do I download a table into EXCEL?

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