SESTAT Survey Design and Methodology

Target Population and
Coverage

Component Surveys

Sample Designs

Data Collection

Editing Guidelines and
Procedures

Missing Data Imputation

Weighting Strategy

Target Population and Coverage

The target population for a data system is the specific population about which information is desired. The SESTAT target population includes residents of the United States with at least a bachelor's degree and who, as of the survey reference period, were

• noninstitutionalized,
• 75 years of age or less, and
• either educated in a science or engineering (S&E) field, or working in an S&E occupation.

More specifically, the U.S. resident (1) had to have at least one bachelor's or a higher degree in an S&E field as of June 30 of the previous year, or (2) had to have at least a bachelor's degree in a non-S&E field and had to be working in an S&E occupation as of the survey reference week (the week of April 15, 1993; April 15, 1995; April 15, 1997; April 15, 1999; or April 15, 2001).

Coverage problems are found in most surveys and analysts should be careful to understand the shortcomings of the data and how that might effect the analysis planned. For example, SESTAT does not cover degrees between the reference date of the survey (April 15, 19xx) and the preceding July 1. Accordingly analysis on the first few months of an individual's career is limited.

Groups Not Covered in 1993

Within the coverage defined above, some bachelor's- and master's-level people were not included in the 1993 surveys. Not covered groups include:

• Those living abroad as of the decennial census (4/1/90) who later came to live in the US. However, if these individuals earned an S&E degree from a US institution after 4/1/90, they are covered. SESTAT does cover U.S. armed forces stationed abroad during the 1990 census.
• Those living in the US who earned an S&E degree after 4/1/90 from a foreign institution and were in the US as of the survey reference date. If the individual holds both a foreign and US degree, they are covered in SESTAT.
• Those over 75 years old, or living in an institution, or living abroad as of the survey reference date

Doctorate-level, S&E-trained people not surveyed in 1993 were predominately U.S. residents who received an S&E doctorate after June 1992 or earned that degree at a foreign institution, who had no degree of any type in any field as of April 1, 1990, and:

• who had not received a bachelor's or master's S&E degree from a U.S. institution between April 1, 1990 and June 30, 1992 or
• who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad.

Groups Not Covered in 1995

Similar groups were not surveyed, and therefore not included in SESTAT, in 1995. The following bachelor's- and master's-level people were not included:

• U.S. residents whose S&E bachelor's and/or master's degrees were either received before April 1990 or were earned at a foreign institution, and who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad
• U.S. residents who had no degree of any type in any field as of April 1, 1990 but who were awarded an S&E degree after June 1994 by a U.S. institution or after April 1990 by a foreign institution.

Doctorate-level, S&E trained people not surveyed in 1995 were predominately U.S. residents who received an S&E doctorate either after June 1994 or earned that degree at a foreign institution, who had no degree of any kind in any field as of April 1, 1990, and:

• who did not receive a bachelor's or master's S&E degree from a U.S. institution between April 1, 1990 and June 30, 1994 or
• who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad.

Groups Not Covered in 1997

Like the earlier years, some groups were not surveyed, and therefore not included in SESTAT, in 1997. The following bachelor's- and master's-level people were not included:

• U.S. residents whose S&E bachelor's and/or master's degrees were either received before April 1990 or were earned at a foreign institution, and who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad
• U.S. residents who had no degree of any type in any field as of April 1, 1990 but who were awarded an S&E degree after June 1996 by a U.S. institution or after April 1990 by a foreign institution.

Doctorate-level, S&E trained people not surveyed in 1997 were predominately U.S. residents who received an S&E doctorate either after June 1996 or earned that degree at a foreign institution, who had no other degree of any type in any field as of April 1, 1990, and:

• who did not receive a bachelor's or master's S&E degree from a U.S. institution between April 1, 1990 and June 30, 1996 or
• who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad.

Groups Not Covered in 1999

Like the earlier years, some groups were not surveyed, and therefore not included in SESTAT, in 1999. The following bachelor's- and master's-level people were not included:

• U.S. residents whose S&E bachelor's and/or master's degrees were either received before April 1990 or were earned at a foreign institution, and who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad
• U.S. residents who had no degree of any type in any field as of April 1, 1990 but who were awarded an S&E degree after June 1998 by a U.S. institution or after April 1990 by a foreign institution.

Doctorate-level, S&E trained people not surveyed in 1999 were predominately U.S. residents who received an S&E doctorate either after June 1998 or earned that degree at a foreign institution, who had no other degree of any type in any field as of April 1, 1990, and:

• who did not receive a bachelor's or master's S&E degree from a U.S. institution between April 1, 1990 and June 30, 1998 or
• who resided outside the U.S. on April 1, 1990 but were not part of the U.S. armed forces stationed abroad.

Groups Not Covered in 2001

Like the earlier years, some groups were not surveyed, and therefore not included in SESTAT, in 2001. As noted above, the National Survey of College Graduates was not conducted in 2001. Therefore, only information on those included in the NSRCG and SDR samples are available for 2001:

• The 2001 NSRCG included those who received bachelor's or master's degrees in an S&E field from a U.S. educational institution between July 1, 1998 and June 30, 2000.
• The 2001 SDR includes those who received doctoral degrees in an S&E field from U.S. educational institution between January 1, 1942 and June 30, 2000. 

Information on individuals not covered by the 2001 NSRCG or 2001 SDR is not available in 2001.

Multiple Coverage (Survey Population Overlap)

Some scientists and engineers had multiple chances of selection because they were linked to the sampling frames for more than one SESTAT component survey. This frame characteristic is referred to as multiplicity. For example, a U.S. resident who received a bachelor's degree before 1990, went on to complete a master's degree in statistics in June 1990, and then earned a doctorate degree in June 1992 could have been selected for all three 1993 surveys. See "Weighting Strategy" for a discussion of how the SESTAT weights compensate for these multiple chances of selection.