The number of postdocs reported by the annual Survey of Graduate Students and Postdoctorates in Science and Engineering  (GSS) jumped 10% between 2009 and 2010, and 25% between 2007 and 2010, according to a National Science Foundation (NSF) "InfoBrief " issued in September. This striking increase does not appear to reflect a vast new influx of researchers into America’s academic labs, however. Those growth rates, which "are the highest in the history" of the survey, instead reflect not only growing cohorts of postdocs but also "improved reporting" of their numbers, the brief explains.
Between 2007 and 2010, NSF and the National Institutes of Health, which cooperate in producing the GSS, changed the study's methodology in an effort to "reduce known reporting problems on the postdoc counts," the brief continues. The brief says that the revised procedures involved:
With those new measures in place, the survey counted 63,415 postdocs. How likely is this disconcertingly precise figure to also be accurate? NSF itself isn't sure. "The overall impact of these methodological changes on the postdoc data is difficult to estimate," the InfoBrief says. Estimates over the years by other observers have varied widely. The 2008 Science and Engineering Indicators put the total as high as 90,000.
Despite billing itself as the place "where discoveries begin," NSF has for years failed to discover how many postdocs work in America’s universities, many of them supported by NSF's own grants. NSF isn't alone in its ignorance. Bridges to Independence , a study published by the National Academies in 2005, bemoaned the "very limited data on this contingent. … Despite the large size of the NIH-supported postdoctoral population, insufficient data are available on this group, with almost no data available on postdoctoral researchers funded through R01s (despite the predominance of this funding mechanism for postdoctoral researchers)."
And many universities, which otherwise pride themselves on their data-collection prowess, have evinced an amazing lack of curiosity about the number of postdocs on their own campuses. The University of California (UC) system was something of a pioneer when, in 2005 , a new, system-wide plan to provide health insurance to all postdocs forced administrators to come up with a firm number. (Ironically, having an exact count made it possible for UC postdocs to mount a successful unionization campaign . Could this be one reason universities don’t want to announce precise figures?)
In 2008, we noted  that a report  from a committee chaired by Nobel laureate Thomas Cech found that "[k]ey questions cannot be answered because no agency has collected certain critical information, such as the size of the early-career pool," including postdocs.
Four years later, in July 2012, as we also noted , NIH's Biomedical Workforce Task Force, chaired by former Princeton University president Shirley Tilghman, bemoaned in a report  that "[t]here are very little reliable data on the number of postdoctoral researchers in the US and the length of their training. … This is due to a dearth of information about the numbers of foreign-trained postdoctoral researchers, as well as changes in the titles of postdoctoral researchers as they proceed through their postdoctoral positions. The lack of reliable estimates of the population size and rates at which people enter and leave the postdoctoral pool complicated the analysis." The report made specific recommendations to address the lack of data.
Any improvement in the dismal record of counting postdocs, no matter how inadequate, is welcome. But we are still a long way from knowing how many such workers there really are.