Typically, postdoctoral fellows ("postdocs") have temporary appointments involving full-time research or scholarship, the purpose of which is to further their education and training. The titles associated with these positions and the conditions of employment vary widely. The status of postdoctoral fellows within the academic hierarchy is not well defined and varies among institutions, although it is generally accepted that the postdoctoral experience represents the last step of a person's training for becoming an independent investigator and faculty member (COSEPUP 2000). Postdoctoral fellows also are important contributors to academic research. They bring a new set of techniques and perspectives to the laboratory that broadens research teams' experience and can make them more competitive for additional research funding. Chapter 3 provides more detail on postdoctoral employment, including reasons for and length of postdoc appointments, salaries and subsequent employment. Chapter 5 provides more detail on postdocs in the academic R&D setting.
Since 1993, the number of S&E postdocs at U.S. universities increased from 34,300 to 49,300 in fall 2006 (appendix table
Noncitizens account for much of the increase in the number of S&E postdocs, especially in biological sciences and medical sciences (figure
An increasing share of academic S&E postdocs are funded through federal research grants. In fall 2006, 56% of S&E postdocs at U.S. universities were funded through this mechanism, up from 52% in 1993. Federal fellowships and traineeships funded a declining share of S&E postdocs: 13% in 2006, down from 17% in 1993. In 2006, 31% of S&E postdocs were funded through nonfederal sources (table