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Counts of Postdoctoral Appointees in Science, Engineering, and Health Rise with Reporting Improvements

NSF 13-334 | September 2013 | PDF format. PDF  
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by Peter Einaudi, Ruth Heuer, and Patricia Green[1]

The total number of postdoctoral appointees (postdocs) reported in the 2010 Survey of Graduate Students and Postdoctorates in Science and Engineering (GSS) grew to 63,415 in 2010, an increase of 10% over the 2009 total and 25% over the 2007 total. These 1- and 3-year growth rates are the highest in the history of the GSS and likely reflect improved reporting, as well as the continued expansion of postdoc employment in academia.

This InfoBrief assesses the impact of methodological changes to the GSS to reduce known reporting problems on the postdoc counts reported. Because the methodological changes began in 2007, analyses gauging the impact of the changes are based on the growth since 2006. As seen in figure 1, the number of postdocs reported in the GSS has climbed steadily over the duration of the survey, with a marked increase from 2007 through 2010. The results of this examination suggest that the 2010 postdoc data are the most accurate and comprehensive to date and that aggregate trends by discipline and demographics were largely unaffected by recent changes in reporting.


FIGURE 1. Postdocs in science, engineering, and health: 1979–2010.

  Figure 1 Source Data: Excel file

Key Trends: 1979–2010

Postdoc Employment by Discipline

The GSS has collected data on postdocs annually since 1979. These data are widely used to estimate the trends seen in postdoc employment over the past 30 years. The dominant trend seen over this period has been the expansion of postdoc employment within and across disciplines (table 1). Because of the extra variability that may have resulted from the methodological changes made in the 2007 through 2010 GSS, all growth rate calculations comparing pre- and post-2007 counts are rounded to the nearest 5%. (See "Data Source and Limitations" for more information.)

TABLE 1. Postdocs in science, engineering, and health, by field: 1979–2010
Percent change b
Field 1979 1980 1990 2000 2006 2007 olda 2007 newa 2008 2009 2010 1979–
2010
1980–
90
1990–
2000
2000–
10
2007new–
10
2009–
10
All surveyed fields 18,101 18,399 29,565 43,115 49,343 50,712 50,840 54,164 57,805 63,415 245 60.7 45.8 45 25 10
Science and engineering 13,586 14,023 21,803 30,224 34,887 35,894 36,223 38,203 40,804 44,051 215 55.5 38.6 45 20 10
Science 12,519 13,042 19,853 26,911 30,245 30,986 31,281 32,741 34,388 37,095 185 52.0 35.6 40 20 10
Agricultural sciences 228 259 536 822 927 948 985 1,147 1,083 1,195 360 106.9 53.4 45 20 10
Biological sciences 6,866 7,083 11,909 16,734 18,807 19,218 19,109 19,827 20,159 21,537 205 68.1 40.5 30 15 5
Communicationa ne ne ne ne ne ne 30 32 38 60 - - - - 100 60
Computer sciences 38 43 71 344 467 516 456 493 594 748 1,640 65.1 384.5 115 65 25
Earth, atmospheric, and ocean sciences 315 312 594 1,155 1,495 1,322 1,250 1,339 1,424 1,760 465 90.4 94.4 50 40 25
Family and consumer sciences/ human sciencesa ne ne ne ne ne ne 8 19 22 30 - - - - 275 35
Mathematical sciences 162 162 249 385 579 621 624 723 737 756 365 53.7 54.6 95 20 5
Multidisciplinary/interdisciplinary studiesa ne ne ne ne ne ne 244 348 459 765 - - - - 215 65
Neurosciencea na na na na na na 285 343 645 818 - - - - 185 25
Physical sciences 4,056 4,279 5,592 6,270 6,703 6,760 6,719 6,885 7,447 7,703 80 30.7 12.1 25 15 5
Psychology 454 475 464 730 873 1,106 1,088 1,077 1,219 1,077 125 -2.3 57.3 50 0 -10
Social sciences 400 429 438 471 394 495 483 508 561 646 50 2.1 7.5 35 35 15
Engineering 1,067 981 1,950 3,313 4,642 4,908 4,942 5,462 6,416 6,956 610 98.8 69.9 110 40 10
Aerospace engineering 32 20 67 111 165 178 178 154 168 191 855 235.0 65.7 70 5 15
Agricultural engineering 29 13 34 56 116 139 139 135 110 119 815 161.5 64.7 115 -15 10
Architecturea na na na na na na 5 11 22 10 - - - - 100 -55
Biomedical engineering 28 25 71 220 591 640 640 710 960 1,036 4,045 184.0 209.9 370 60 10
Chemical engineering 192 185 557 703 735 758 790 880 1,084 1,092 490 201.1 26.2 55 40 0
Civil engineeringa 128 122 168 295 458 419 417 465 535 570 365 37.7 75.6 95 35 5
Electrical engineering 142 123 242 525 721 885 884 987 1,025 1,097 790 96.7 116.9 110 25 5
Engineering science 74 79 76 163 224 192 183 214 226 243 210 -3.8 114.5 50 35 10
Industrial engineering 8 16 6 48 51 73 71 115 109 163 920 -62.5 700.0 240 130 50
Mechanical engineering 143 137 222 480 644 725 722 784 948 1,009 635 62.0 116.2 110 40 5
Metallurgical/materials engineering 209 172 363 507 571 555 564 605 758 835 385 111.0 39.7 65 50 10
Mining engineering 5 3 19 8 11 4 5 5 4 6 100 533.3 -57.9 -25 20 50
Nuclear engineering 20 22 30 40 85 77 73 85 90 107 385 36.4 33.3 170 45 20
Petroleum engineering 6 6 15 20 18 22 22 28 36 46 665 150.0 33.3 130 110 30
Engineering, nec 51 58 80 137 252 241 249 284 341 432 645 37.9 71.3 215 75 25
Health 4,515 4,376 7,762 12,891 14,456 14,818 14,617 15,961 17,001 19,364 345 77.4 66.1 50 30 15
Clinical medicinea 4,035 3,899 6,945 11,555 12,584 12,805 12,472 13,837 14,601 16,610 325 78.1 66.4 45 35 15
Other health 480 477 817 1,336 1,872 2,013 2,145 2,124 2,400 2,754 475 71.3 63.5 105 30 15

- = not calculable. na = not applicable. ne = not eligible; data were not collected for this field before 2007.

nec = not elsewhere classified.

a In 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007; "2007old" shows data as they would have been collected in prior years. See "Data Source and Limitations" for more detail.
b Percent change estimates including counts from 2007 or 2010 are rounded to the nearest 5% to reflect potential imprecision of this estimate due to methodological changes in those survey cycles.

SOURCE: National Science Foundation, National Center for Science and Engineering Statistics, NSF-NIH Survey of Graduate Students and Postdoctorates in Science and Engineering.

Table 1 Source Data: Excel file

The GSS data show that the number of postdocs increased across all science, engineering, and health (SEH) fields, with most fields experiencing substantial growth in each decade since 1980. Over the past decade (2000–10), postdoc employment in engineering had the fastest growth, with 8 of 14 engineering fields more than doubling the number of postdocs employed within them. Among the sciences, only computer sciences had a similar rate of growth.

As in 1979, the most common fields for postdocs in 2010 were the biological sciences, clinical medicine, and physical sciences fields. Even though the number of postdocs employed in the physical sciences has nearly doubled since 1979 (figure 2), the proportion of SEH postdocs in the physical sciences has declined substantially over time, dropping from 22.4% of all SEH postdocs in 1979 to 12.1% in 2010. By contrast, the proportion of SEH postdocs in engineering increased substantially over time, increasing from 5.9% of all postdocs in 1979 to 11.0% in 2010.


FIGURE 2. Postdocs in science, engineering, and health, by field: 1979–2010.

  Figure 2 Source Data: Excel file

As part of the 2007 survey redesign, five new fields (communication, family and consumer sciences/human sciences, multidisciplinary/interdisciplinary studies, neuroscience, and architecture) were added to the list of GSS eligible fields.[2] As seen in table 1, the number of postdocs in each of these fields has grown substantially since the fields were introduced to the GSS in 2007, especially in neuroscience and multidisciplinary/interdisciplinary studies. However, as shown in figure 2, these five new fields account for a small proportion of all postdocs. Because many of these postdocs were likely to have been reported under other SEH fields before the expansion of the GSS eligible fields list, the impact of these additional fields had limited effect on the overall increase in postdocs. Of the 1,673 postdocs reported in these new fields in 2010, a total of 913 were in units that existed under different GSS fields in 2006. Therefore, adding these five new fields accounted for an additional 760 postdocs, approximately 5% of the overall increase of approximately 14,100 in postdoc counts from 2006 to 2010.

Postdoc Employment by Demographic Characteristics

Women constituted 38.1% of the postdoc workforce in 2010, up from 18.5% in 1979 (table 2). Following 2 decades of growth, the proportion of foreign postdocs holding temporary visas leveled off in the early 2000s and declined from 2007 to 2009.

TABLE 2. Institutional (2010 Carnegie) classification and sex, citizenship, ethnicity, and race of postdocs in science, engineering, and health: 1979–2010
Percent changeb
Characteristic 1979 1980 1990 2000 2006 2007olda 2007newa 2008 2009 2010 1979– 2010 1980– 90 1990– 2000 2000– 10 2007new– 10 2009– 10
All postdocs 18,101 18,399 29,565 43,115 49,343 50,712 50,840 54,164 57,805 63,415 250 60.7 45.8 45 25 10
Male 14,761 14,856 21,572 29,606 31,760 32,860 32,942 33,943 35,987 39,249 165 45.2 37.2 35 20 10
Female 3,340 3,543 7,993 13,509 17,583 17,852 17,898 20,221 21,818 24,166 625 125.6 69.0 80 35 10
U.S. citizens and permanent
residentsc
12,036 11,893 15,115 19,452 21,147 22,022 22,103 24,915 27,105 29,769 145 27.1 28.7 55 35 10
Hispanic or Latino na na na na na na na na na 1,160 - - - - - -
Not Hispanic or Latino
American Indian or Alaska Native na na na na na na na na na 93 - - - - - -
Asian na na na na na na na na na 5,174 - - - - - -
Black or African American na na na na na na na na na 898 - - - - - -
Native Hawaiian or Other Pacific Islander na na na na na na na na na 92 - - - - - -
White na na na na na na na na na 15,689 - - - - - -
More than one race na na na na na na na na na 140 - - - - - -
Unknown ethnicity or race na na na na na na na na na 6,523 - - - - - -
Temporary visa holders 6,065 6,506 14,450 23,663 28,196 28,690 28,737 29,249 30,700 33,646 455 122.1 63.8 40 15 10
Institutional classification
Research universities (very high research activity) 14,633 15,086 23,996 34,827 39,535 40,422 40,500 43,243 46,221 50,852 250 59.1 45.1 45 25 10
Research universities (high research activity) 1,122 1,187 1,859 2,588 2,703 3,020 3,041 3,242 3,557 3,608 220 56.6 39.2 40 20 0
Doctoral universities 298 287 227 456 525 574 574 577 652 682 130 -20.9 100.9 50 20 5
Medical and other health institutions 1,721 1,560 3,014 4,281 5,436 5,522 5,551 5,873 6,149 6,789 295 93.2 42.0 60 20 10
Other institutions 327 279 469 963 1,144 1,174 1,174 1,229 1,226 1,484 355 68.1 105.3 55 25 20

- = not calculable; na = not applicable.

a In 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007; "2007old" shows data as they would have been collected in prior years. See "Data Source and Limitations" for more detail.
b Percent change estimates including counts from 2007 or 2010 are rounded to the nearest 5% to reflect potential imprecision of this estimate due to methodological changes in those survey cycles.
c Ethnicity and race data are available only for U.S. citizens and permanent residents. See "Data Source and Limitations" for more detail on changes in the reporting of ethnicity and race.

SOURCE: National Science Foundation, National Center for Science and Engineering Statistics, NSF-NIH Survey of Graduate Students and Postdoctorates in Science and Engineering.

Table 2 Source Data: Excel file

In 2010 the postdoc section was expanded to include data on the race and ethnicity of U.S. citizens and permanent residents. This key change was part of a larger expansion of the postdoc data collection designed to meet the analytical needs of the postdoc community, and it is discussed in greater detail below (see "Methodological Changes: 2007–10"). The 2010 GSS postdoc data indicate that blacks or African Americans and Hispanics or Latinos are significantly underrepresented within the postdoc ranks (table 2). Among all U.S. citizen and permanent resident postdocs in 2010, only 3.0% were black or African American and 3.9% were Hispanic or Latino. These figures are less than half of the percentages seen among graduate students enrolled in SEH fields in 2010 (8.0% and 7.3%, respectively) and even lower than the percentages found in the adult U.S. citizen population aged 21–45 (13.8% and 11.9%, respectively).[3]

Units Reporting Postdocs

A final indicator of the increasing prevalence of postdocs in SEH disciplines is the growth of the number of institutions and units (academic departments, programs, research centers, or health care facilities) reporting one or more postdocs. From 1979 through 2006, the number of institutions in the GSS that reported postdocs was relatively stable, whereas the number of units within institutions reporting postdocs grew steadily (table 3).[4]

TABLE 3. Institutions and units reporting one or more postdocs and total postdoc counts in science, engineering, and health: 1979–2010
Institutions Units Postdocs
Year Number Percent Number Percent 1-year
growth rate
3-year
growth rate
Number 1-year
growth rate
3-year
growth rate
1979 254 40.4 2,657 27.4 - - 18,101 - -
1980 255 40.7 2,686 27.4 1.1 - 18,399 1.6 -
1981 258 41.5 2,719 28.0 1.2 - 19,634 6.7 -
1982 258 42.4 2,667 27.8 -1.9 0.4 19,363 -1.4 7.0
1983 272 44.7 2,810 29.7 5.4 4.6 20,712 7.0 12.6
1984a 264 64.1 2,865 32.6 2.0 5.4 21,535 4.0 9.7
1985a 260 63.1 2,919 32.8 1.9 9.4 22,387 4.0 15.6
1986a 253 61.4 2,941 32.7 0.8 4.7 23,721 6.0 14.5
1987a 257 61.8 3,008 33.0 2.3 5.0 24,881 4.9 15.5
1988 267 44.1 3,020 30.2 0.4 3.5 26,123 5.0 16.7
1989 263 43.2 3,126 30.7 3.5 6.3 27,932 6.9 17.8
1990 264 43.3 3,255 31.4 4.1 8.2 29,565 5.8 18.8
1991 274 45.0 3,429 32.4 5.3 13.5 30,865 4.4 18.2
1992 267 43.9 3,565 32.8 4.0 14.0 32,747 6.1 17.2
1993 269 44.4 3,723 33.5 4.4 14.4 34,322 4.8 16.1
1994 272 45.0 3,838 33.8 3.1 11.9 36,377 6.0 17.9
1995 270 44.8 3,763 32.5 -2.0 5.6 35,926 -1.2 9.7
1996 270 44.8 3,755 32.4 -0.2 0.9 37,107 3.3 8.1
1997 271 45.1 3,809 32.9 1.4 -0.8 38,481 3.7 5.8
1998 274 45.6 3,806 32.6 -0.1 1.1 40,086 4.2 11.6
1999 268 44.7 3,886 32.9 2.1 3.5 40,800 1.8 10.0
2000 266 44.6 3,954 33.2 1.7 3.8 43,115 5.7 12.0
2001 257 42.8 3,840 32.1 -2.9 0.9 43,311 0.5 8.0
2002 260 43.6 3,980 32.8 3.6 2.4 45,034 4.0 10.4
2003 257 43.3 3,997 32.6 0.4 1.1 46,728 3.8 8.4
2004 261 44.2 4,039 32.9 1.1 5.2 47,240 1.1 9.1
2005 261 44.4 4,146 33.7 2.6 4.2 48,555 2.8 7.8
2006 274 46.6 4,259 34.6 2.7 6.6 49,343 1.6 5.6
2007oldb 283 48.6 4,471 36.3 5.0 10.7 50,712 2.8 7.3
2007newb 283 48.6 4,495 35.6 - - 50,840 - -
2008 289 49.9 4,843 36.8 7.7 16.8 54,164 6.5 11.6
2009 297 51.7 5,130 38.6 5.9 20.5 57,805 6.7 17.1
2010 326 56.8 5,636 41.1 9.9 25.4 63,415 9.7 24.7

- = not calculable.

a From 1984 to 1987, the number of participating institutions dropped substantially as master's-granting institutions were subsampled and counts were imputed for the nonsampled institutions within two dummy institutions titled Unsampled Public Master's and Unsampled Private Master's. As a result, the proportion of institutions reporting postdocs is not comparable to cycles prior to 1984 or after 1987.
bIn 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007; "2007old" shows data as they would have been collected in prior years. See "Data Source and Limitations'" for more detail.

SOURCE: National Science Foundation, National Center for Science and Engineering Statistics, NSF-NIH Survey of Graduate Students and Postdoctorates in Science and Engineering.

Table 3 Source Data: Excel file

As shown in table 3, the number and proportion of units reporting postdocs has increased almost every year since 1979. These increases serve as key indicators of the expansion of postdoc employment in the U.S. academic sector. However, the large increases in the number of units reporting postdocs since 2007 are due at least in part to methodological changes.

Methodological Changes: 2007–10

The recent rates of growth in institutions and units reporting postdocs and the count of postdocs were influenced, in part, by methodological changes between 2007 and 2010. In addition to the expansion of the GSS eligible fields discussed above, the National Science Foundation (NSF) and the National Institutes of Health (NIH) authorized four key changes in the GSS data collection designed to improve postdoc reporting (year of implementation in parentheses):

  • Replacing the term "department" with "organizational unit" to capture nontraditional department-like places where postdocs work (2007)
  • Encouraging schools to designate a coordinator specifically for reporting postdoc data (2008–10)
  • Expanding the postdoc data items to collect more detailed counts by ethnicity, race, source and mechanism of support, and type and origin of doctoral degree (2010)
  • Sending letters to institution presidents with a formal request to designate a Postdoc Coordinator and to increase institutions' participation in the postdoc data improvement efforts (2010)

Change in Terminology

The change in terminology from "department" to "organizational unit" was implemented in 2007 to explicitly include nontraditional departments and places were postdocs are employed, such as laboratories, centers, and other affiliated research units. This change was made because postdocs in these units may have been omitted in prior cycles because of the survey's focus on academic departments enrolling graduate students.

The increased reporting of postdocs in nondegree granting units (e.g., research centers and laboratories) in the GSS institutions is a key driver of the overall increase in postdoc counts from 2007 to 2010 (figure 3). After being relatively stable for over 20 years, the number of nondegree granting units reporting postdocs increased substantially between 2007 and 2010. Of the 21,393 postdocs reported in nondegree granting units in 2010, a total of 6,105 were in units added since 2006, representing 43.4% of the overall 14,072 increase in postdoc counts from 2006 to 2010.


FIGURE 3. Number of GSS eligible units, units reporting postdocs and postdoc counts, by units' highest-degree-granting status: 1979–2010.

  Figure 3 Source Data: Excel file

Postdoc Coordinator and Postdoc Data Expansion

Over the past decade, research sponsored by NSF and NIH consistently suggested that postdocs were being underreported in the GSS and other studies and that more detailed information, similar to what GSS collects on the graduate students, was needed to better understand the postdoc labor market.[5] Among the factors leading to difficulties in accurate reporting of postdoc data were institutional differences in how postdocs were defined and tracked and the lack of centralized recordkeeping systems for postdocs.

To improve the access and accuracy of the GSS postdoc data, NSF has been working with GSS institutions to identify individuals best qualified to provide their institution's postdoc data. Until 2008, schools typically appointed a School Coordinator (SC) to be responsible for reporting both student and postdoc data. To improve reporting, NSF was interested in the efficacy of appointing two coordinators: a Student Coordinator (StC) to report the graduate enrollment data and a Postdoc Coordinator (PC) to report information on postdocs and other nonfaculty doctorate researchers. In 2008, a total of 19 PCs were identified and given the ability to report the postdoc data for their schools and units independently from the graduate student data collection. In 2009, a Postdoc Pilot Study was conducted to determine (1) whether schools could provide detailed data on their postdocs' race and ethnicity, source of financial support, and type of doctorate degrees held and (2) whether having a separate PC would improve postdoc reporting. The results of the study, which included 48 small schools and 20 larger schools, confirmed the viability of both.[6]

A final objective of the 2009 Postdoc Pilot Study was to identify the common characteristics of a postdoc position across institutions. Respondents were asked to indicate which common characteristics of postdoc positions were applicable to postdocs at their institution. The following characteristics were reported by more than 80% of responding institutions:

  • Requires a PhD or an equivalent doctorate degree
  • Provides training in research
  • Is intended to advance professional skills
  • Requires that the postdoc work be under the direction of a senior scholar
  • Is intended to prepare the postdoc for an independent career in research

These characteristics matched well with the GSS definition, which focuses on recent doctorate recipients with limited-term appointments primarily intended for training under the supervision of a senior scholar. The results also confirmed the substantial variation across institutions and identified the need to collect this information across all GSS institutions.

Because of the success of the Postdoc Pilot Study, the postdoc section of the 2010 GSS survey was substantially expanded to align with the graduate student items and to include questions concerning the criteria used to define postdocs. All schools were also requested by NSF to designate a separate PC as needed.

Letter to Institution Presidents

To highlight these survey changes and to increase institutions' participation in the postdoc data improvement efforts, a letter was sent from NSF and NIH in 2010 to the president of each institution emphasizing the importance of postdoc data in GSS and providing summary information on the postdoc counts reported by their institution in the 2008 and 2009 GSS. If these data were not accurate, the letter asked the president to designate a PC.

In 2010, a total of 125 schools opted to split the GSS data collection responsibilities between a StC and a PC. Of the 567 schools that retained a single SC, 104 schools replaced the 2009 SC with a new SC. table 4 and 5 show the results of these changes, by looking at changes in postdoc reporting by coordinator type.

Several key distinctions were found between schools that used PCs and those that did not (table 4). First, schools where postdocs were spread across many units were more likely to use a PC than were schools where the postdocs were concentrated within a few units. Postdocs were reported in a higher proportion of units in schools with a PC than in schools that had a single SC. For example, 68.1% of the units in schools with a PC in 2008 had postdocs as compared to 36.1% of the units in schools with an SC.

TABLE 4. Changes in organizational unit counts, by coordinator type and unit add-drop status: 2001–10
Units with 1 or more postdocs Percentage of units with postdocs
Year Coordinator
type
All unitsa Total Added Dropped Extant Total Added Dropped Extant
2001 SC 12,010 3,840 66 -48 3,774 32.0 0.5 -0.4 31.4
2002 SC 12,166 3,980 148 -40 3,832 32.7 1.2 -0.3 31.5
2003 SC 12,315 3,997 87 -54 3,910 32.5 0.7 -0.4 31.7
2004 SC 12,352 4,039 113 -84 3,926 32.7 0.9 -0.7 31.8
2005 SC 12,353 4,146 153 -56 3,993 33.6 1.2 -0.5 32.3
2006 SC 12,395 4,259 127 -75 4,132 34.4 1.0 -0.6 33.3
2007oldb SC 12,482 4,471 225 -157 4,246 35.8 1.8 -1.3 34.0
2007newb SC 12,629 4,495 24 0 4,471 35.6 0.2 0.0 35.4
2008 SC 12,910 4,659 288 -82 4,371 36.1 2.0 -0.6 33.9
2008 New PC 270 184 32 -7 152 68.1 11.9 -2.6 56.3
2009 SC 12,525 4,740 192 -64 4,548 37.8 1.5 -0.5 36.3
2009 New PC 475 203 55 0 148 42.7 11.6 0.0 31.2
2009 Prior PC 248 187 0 -1 187 75.4 0.0 -0.4 75.4
2010 SC 10,583 3,941 284 -55 3,657 37.2 2.7 -0.5 34.6
2010 New PC 2,680 1,385 235 -39 1,150 51.7 8.8 -1.5 42.9
2010 Prior PC 572 310 0 -30 310 54.2 0.0 -5.2 54.2

PC = Postdoc Coordinator; prior PC = PC in schools that used a PC in a prior survey cycle; SC = School Coordinator.

a Represents the total number of units that were assessed by the coordinator, and includes units that were dropped during data collection because they no longer had postdocs.
b In 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007; "2007old" shows data as they would have been collected in prior years. See "Data Source and Limitations" for more detail.

SOURCE: National Science Foundation, National Center for Science and Engineering Statistics, NSF-NIH Survey of Graduate Students and Postdoctorates in Science and Engineering.

Table 4 Source Data: Excel file

Second, new PCs were much more likely to add new units than were SCs or PCs in schools that had designated a PC in a prior cycle; new units with postdocs represented 11.9%, 11.6%, and 8.8% of all units in schools with new PCs in 2008, 2009, and 2010, respectively. As shown in table 5, of the 63,415 postdocs reported in 2010, a total of 2,358 were in units added by PCs in the prior three cycles, representing 16.8% of the overall 14,072 increase in postdoc counts from 2006 to 2010 (table 3).

Finally, as shown in table 4, in both 2009 and 2010 no new postdoc units were added within schools that currently had a PC and had used a PC in a prior cycle. Together, these differences provide substantial evidence that new PCs improved survey coverage by adding previously unreported, but eligible, units. These findings also suggest that improvements in coverage are a one-time phenomenon occurring the year a PC is added.

Table 5 provides additional evidence that the addition of a PC improved postdoc reporting and that this effect was primarily felt in the year the PC was added. As seen in the percentage change for the prior year, new PCs increased overall postdoc reporting in their schools by 17.0% in 2008, 46.6% in 2009, and 15.6% in 2010. Each of these increases is significantly higher than was typical prior to 2008 and greater than their peers (SC and PC in a school that had used a PC in a prior year) in each of these years. Although some of the increases in postdoc counts reported by new PCs were associated with newly added units, new PCs also increased the number of postdocs reported within extant units at a higher rate than SCs or PCs in schools that had designated a PC in a prior cycle.

TABLE 5. Changes in postdoc counts, by coordinator type: 2001–10
Postdocs Percent change from prior year
Year Coordinator
type
Prior total Current
total
In added
units
In dropped
units
In extant
units
Total In added
units
In dropped
units
In extant
units
2001 SC 43,115 43,311 416 -455 235 0.5 1.0 -1.1 0.5
2002 SC 43,311 45,034 993 -300 1,030 4.0 2.3 -0.7 2.4
2003 SC 45,034 46,728 499 -368 1,563 3.8 1.1 -0.8 3.5
2004 SC 46,728 47,240 1,901 -960 -429 1.1 4.1 -2.1 -0.9
2005 SC 47,240 48,555 879 -352 788 2.8 1.9 -0.7 1.7
2006 SC 48,555 49,343 1,777 -1,076 87 1.6 3.7 -2.2 0.2
2007olda SC 49,343 50,712 2,199 -1,827 997 2.8 4.5 -3.7 2.0
2007newa SC 50,712 50,840 128 - - 0.3 0.3 - -
2008 SC 45,131 47,482 1,665 -606 1,292 5.2 3.7 -1.3 2.9
2008 New PC 5,709 6,682 498 -124 599 17.0 8.7 -2.2 10.5
2009 SC 46,303 49,394 1,268 -272 2,095 6.7 2.7 -0.6 4.5
2009 New PC 1,179 1,729 354 0 196 46.6 30.0 0.0 16.6
2009 Prior PC 6,682 6,682 0 -1 1 0.0 0.0 0.0 0.0
2010 SC 36,353 39,760 2,444 -416 1,379 9.4 6.7 -1.1 3.8
2010 New PC 13,423 15,519 1,610 -295 781 15.6 12.0 -2.2 5.8
2010 Prior PC 8,029 8,136 0 -171 278 1.3 0.0 -2.1 3.5

- = not calculable.

PC = Postdoc Coordinator; prior PC = PC in schools that used a PC in a prior survey cycle; SC = School Coordinator.

a In 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007; "2007old" shows data as they would have been collected in prior years. See "Data Source and Limitations" for more detail.

SOURCE: National Science Foundation, National Center for Science and Engineering Statistics, NSF-NIH Survey of Graduate Students and Postdoctorates in Science and Engineering.

Table 5 Source Data: Excel file

This finding demonstrates that PCs also improved survey accuracy by adding postdoc counts to units where prior SCs could not. New PCs increased postdoc reporting within extant units by 10.5% in 2008, 16.6% in 2009, and 5.8% in 2010. Finally, increases in postdoc counts were lowest in 2009 and 2010 among schools that had previously used a PC, underscoring the notion that the primary impact of adding a PC is achieved the year the PC is added.

Overall Impact of Methodological Improvements on Postdoc Counts

The overall impact of these methodological changes on the postdoc data is difficult to estimate. Two different ways of estimating the impact can be examined.

First, there is the directly observed impact of the methodological changes. In the 2010 data collection, 7,160 postdocs were reported in 879 units that meet at least one of the following criteria:

  • The unit was added in one of the new fields added to the GSS code list in 2007.
  • The unit was a nondegree granting unit added since 2006.
  • The unit was added by a PC.

This count represents 50.9% of the overall change in the number of postdocs reported from 2006 to 2010.

Another method of estimating the impact would be to assume the growth of postdoc employment would have remained steady over this period. From 1979 through 2006, postdoc employment grew by an average of 1,157 postdocs per year. Based on this average growth, expected growth from 2006 through 2010 is estimated at 4,628 and growth due to the methodological improvement is estimated at 9,444, or 67.1% of the observed growth.

Data Source and Limitations

Cosponsored by NSF and NIH, the GSS is an annual survey that provides data on the number and characteristics of graduate students, postdocs, and other doctorate-holding nonfaculty researchers in science, engineering, or selected health fields in all U.S. academic institutions granting doctorate and research-based master's degrees in these fields.

This InfoBrief is based on data published in the 2010 GSS. The 2010 GSS collected data on the graduate students and postdocs from 13,711 organizational units (departments, programs, affiliated research centers, and health care facilities) at 574 institutions of higher education and their affiliates in the United States, Puerto Rico, and Guam. The institutional response rate was 99.3%. An overview of the survey can be found at http://www.nsf.gov/statistics/srvygradpostdoc/.

In 2007, eligible fields were reclassified, newly eligible fields were added, and the survey was redesigned to improve coverage and coding of eligible units. "2007new" presents data as collected in 2007, and "2007old" presents data as they would have been collected in 2006. Due to methodological changes in 2007, the data collected from 2007 through 2011 are not strictly comparable to those collected prior to 2007. As a result, care should be used when assessing trends within the GSS data. Ten-year trends reported in the tables are labeled "% change 2002–11." Note that these percentages are rounded to the nearest 5% and counts are rounded to the nearest 100 to reflect the extra variability in the estimate that may have resulted from the methodological changes that occurred in 2007. Please see appendix A, "Technical Notes," in Graduate Students and Postdoctorates in Science and Engineering: Fall 2007 (NSF 10-307) for a more detailed discussion of these changes.

Reporting of ethnicity and race in 2008–11 has been affected by changes in reporting of ethnicity and race in the Integrated Postsecondary Education Data System (IPEDS). Starting in 2008, IPEDS respondents were asked to use a new classification that included a category for two or more races (see http://nces.ed.gov/ipeds/reic/resource.asp) and separate reporting of Native Hawaiians and Other Pacific Islanders from Asians. The new classification was optional in 2008 and 2009 IPEDS but mandatory in 2010 and may have contributed to a significant increase in reporting of "Not Hispanic or Latino, More than one race" within the GSS data.

Each of the major methodological changes in GSS resulted in improved reporting of postdoc data. The expansion of the GSS code list in 2007, the change in focus from degree-granting graduate programs to eligible units regardless of degree-granting status, and the appointment of separate PCs improved coverage of postdocs in SEH fields. The expansion of the postdoc data items and appointment of more knowledgeable PCs improved postdoc data reporting within extant units.

In addition to improving the reporting of overall postdoc counts, the 2010 GSS provided more detailed information on postdocs, including the ethnicity and race of U.S. citizens and permanent residents; federal and nonfederal sources of financial support and support mechanism; type of doctoral degree, such as MD, PhD, or joint MD and PhD; and origin of doctoral degree (U.S. or foreign country).[7]

Notes

[1] Peter Einaudi and Ruth Heuer are research analysts and Patricia Green is a survey director at RTI International. For further information, contact Kelly H. Kang, Human Resources Statistics Program, National Center for Science and Engineering Statistics, National Science Foundation, 4201 Wilson Boulevard, Suite 965, Arlington, VA 22230 (kkang@nsf.gov; 703-292-7796).

[2] A complete list of GSS fields can be found in appendix B of Graduate Students and Postdoctorates in Science and Engineering: Fall 2010 (http://www.nsf.gov/statistics/nsf13314/).

[3] Einaudi P. 2011. Two Decades of Increasing Diversity More than Doubled the Number of Minority Graduate Students in Science and Engineering. InfoBrief NSF 11-319. Arlington, VA: National Science Foundation, National Center for Science and Engineering Statistics. Available at http://www.nsf.gov/statistics/infbrief/nsf11319/.

[4] From 1984 to 1987, the number of GSS institutions dropped substantially as master's-granting institutions were subsampled and counts for the nonsampled institutions were imputed within two placeholder institutions labeled as Unsampled Public Master's and Unsampled Private Master's. As a result, the proportion of institutions reporting postdocs prior to 1984 and after 1987 is not comparable.

[5] McFarland E, Einaudi P, Cook S, Richards A, Roe D, Zwieg E, Green P. 2010. GSS Recordkeeping Study. Report to the National Science Foundation. Research Triangle Park, NC: RTI International.

[6] McFarland E, Steele B, Zwieg E, Green P. 2011. GSS Postdoc Pilot Study. Report to the National Science Foundation. Research Triangle Park, NC: RTI International.

[7] National Science Foundation, National Center for Science and Engineering Statistics. 2013. Graduate Students and Postdoctorates in Science and Engineering: Fall 2010. Detailed Statistical Tables NSF 13-314. Arlington, VA. Available at http://www.nsf.gov/statistics/nsf13314/.


National Science Foundation, National Center for Science and Engineering Statistics
Counts of Postdoctoral Appointees in Science, Engineering, and Health Rise with Reporting Improvements
Arlington, VA (NSF 13-334) [September 2013]


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