With the aging of the U.S. population, older individuals are becoming an increasingly important factor in the
health and vitality of the U.S. labor force including that portion in science and engineering
Data from the National Science Foundation's Survey of Doctorate Recipients (SDR) can be used to analyze labor force characteristics of older doctoral scientists and engineers, which can aid in assessing future human resource requirements. The SDR data also facilitate comparison of these characteristics between younger scientists and engineers and those of their older colleagues. This report presents selected results, derived primarily from the 1997 SDR, which illuminate certain labor force characteristics of doctoral scientists and engineers for different age groups. Particular attention is paid to those aged 55 and older.
Initiated in 1973, the SDR is a longitudinal demographic survey of science and engineering doctorate holders conducted every two years for the National Science Foundation (NSF) and other Federal agencies. The SDR database contains information on various educational and work-related characteristics of scientists and engineers, which can be compared for different age groups. The sampling frame for the SDR is the Doctoral Records File (DRF), a census of all research doctorates earned in the U.S. since 1920. The 1997 SDR sample included 54,100 doctoral-level scientists and engineers who were recipients of doctoral degrees in a science or engineering field from a U.S. institution between January 1942 and June 1996, aged 75 or younger, and residing in the U.S. during the week of April 15, 1997. The estimated size of this population is 582,080.
The following results, unless noted, are derived from the 1997 SDR database. A limited number of comparisons are made with results from the 1993 and 1995 SDR's as well as with relevant 1997 data from NSF's Scientists and Engineers Statistical Data System (SESTAT) database. SESTAT is an integrated information system containing employment, education, and demographic data on both doctoral and non-doctoral (i.e., those whose highest degree was a bachelor's or master's degree) scientists and engineers in the United States. In addition, differences in results among the three principal employment sectors for doctoral scientists and engineerseducation, government, and industryare highlighted.
This report aims to shed light on the following questions about the characteristics of U.S. doctoral scientists and engineers:
There appears to be no firm definition of what is meant by "older" scientists and engineers. Within the context of this report, "older" generally refers to those 55 years and up. However, where the data warrant, other age groupings are utilized, which may commence at an age greater than 55.
In this report, doctoral scientists and engineers are defined as individuals having doctoral degrees in one of five science and engineering fields: computer and mathematical sciences; life and related sciences; physical and related sciences, social and related sciences; and engineering. The analysis does not focus on occupations.
 Two U.S. government publications provide a wealth of information about the older population. Older Americans 2000: Key Indicators of Well-Being, released by the Federal Interagency Forum on Aging Related Statistics, reports indicators of population, economics, health status, health risks and behaviors, and health care. In September 2000, the U.S. Census Bureau issued The Older Population in the United States, based on results of the March 1999 Current Population Survey. This latter report summarizes selected economic and social characteristics of the U.S. civilian, non-institutionalized population aged 55 and older.
 See P. Stephan and S. Levin, Striking the Mother Lode in Science: The Importance of Age, Place and Time (New York: Oxford University Press, 1992). Examining the relationship between age and ability to do scientific work, Stephan and Levin reached two main conclusions. First, scientists write less as they age, though this effect is not great for average (versus exceptionally productive) doctoral scientists. Second, there is a stronger relationship between age and exceptional contributions to science, with most such contributions being made before age 40 (pp. 156-7).
 Source: National Science Foundation/Division of Science Resources Statistics, 1997 Survey of Doctorate Recipients. See also note 6.
 Source: National Science Board, Science and Engineering Indicators: 2000 (Arlington, VA: National Science Foundation, 2000 (NSB-00-1)), pp. 3-23.
 SESTAT contains data from three national sample surveys, including the SDR. For further information, see Nirmala Kannankutty and R. Keith Wilkinson, SESTAT: A Tool for Studying Scientists and Engineers in the United States (Arlington, VA: National Science Foundation, Division of Science Resources Statistics, NSF 99-337, 1999).
 In the three-sector employment summary utilized in analyzing SDR results, the education sector consists largely of universities and other institutions of higher education. The industry sector contains large and small businesses, as well as self-employed scientists and engineers.
 To date, information on patents and publications is only available in the 1995 SDR.
 For the limited number of comparisons with scientists and engineers whose highest degree was a bachelor's or a master's degree, as obtained from the SESTAT database, a sixth degree field category, non-science and engineering degree, was included in the degree totals for those two degree levels. This category in SESTAT includes individuals working in science and engineering occupations. For further information, see Kannankutty and Wilkinson, note 5.