Doctorate Recipients from U.S. Universities: Summary Report 2007-08
Trends among Doctorate Recipients
Individual research doctorate recipients from U.S. universities are the primary respondents to the Survey of Earned Doctorates. Throughout this report, the terms "doctorate" and "doctoral degree" are used to represent any of the research doctoral degrees covered by the survey.
Overall Trends and Rates of Change
During the 12-month period ending 30 June 2008, U.S. universities awarded 48,802 research doctoral degrees, compared with 48,112 in 2007 and 45,615 in 2006 (table 1). Although the 2008 total is the largest number of research doctorates awarded in the history of U.S. higher education, the rate of increase over 2007 was small, 1.4% (figure 1).
The long-term trend in the number of new research doctorates is characterized by considerable growth. Since the SED began in 1957, the number of doctorates granted by U.S. universities has, on average, increased by about 3.5% per year. Between 1961—when the number of annual doctorates awarded surpassed 10,000 for the first time—and 1971, the number of doctorates awarded grew at an average annual rate of nearly 12%, and the total almost tripled (31,867). From 1972 to 1985 the growth rate slowed, then declined, and the number of doctorates awarded annually stabilized at about 31,000. In 1986, a second period of growth began that persisted until 1998, when 42,638 research doctorates were awarded. From 1998 to 2002, the number of doctorates awarded fluctuated, reaching a low point in 2002. Growth resumed from 2003 to 2008, leading to an all-time high in 2008 for number of doctorates earned (figure 2, table 1).
The SED project closely monitors the universe of institutions that grant research doctorates, and it annually reviews all accredited institutions recognized by the U.S. Department of Education in its Integrated Postsecondary Education Data System (IPEDS). The data-collection contractor for the SED contacts newly identified institutions, determines whether those institutions grant research doctorates (see appendix A), and adds institutions to the SED universe when they award a qualifying degree. Detailed data tables 45a and 45b display the full list of institutions that granted research doctorates in 2008.
During the 2008 academic year, there were 421 universities in the United States and Puerto Rico that awarded at least one research doctorate. The mean number of doctorates awarded per institution was 116, and the median was 43 (table 2). As the substantial difference between the mean and the median indicates, a relatively small number of institutions award a disproportionately large number of doctorates. The top 10% of institutions granted nearly half (46%) of all doctorates in 2008, and institutions in the 80th to 89th percentiles accounted for more than one fifth (22%) (figure 3).
The trend data in table 2 show that the median number of degrees awarded per institution grew rapidly during the late 1960s, from 43 in 1968 to 55 in 1970. Following the end of the Vietnam War in 1972 and the enrollment boosts that accompanied the availability of student deferments from military service, the median number quickly dropped to 42 in 1973 and has vacillated between 35 and 46 since.
In 2008 the University of California-Berkeley granted the largest number of doctorates, 856, or 2% of all doctorates awarded that year, followed by the University of Texas-Austin (821), the University of Wisconsin-Madison (740), the University of Illinois–Urbana-Champaign (735), and the University of California-Los Angeles (724). In 2008 (as has been the case for the past several years), the 10 institutions awarding the highest number of doctoral degrees granted approximately 15% of all doctorates (table 3, detailed data tables 45a, 45b).
Among the states, California universities led the nation by awarding 5,925 doctorates, or 12% of all doctorates in 2008 (figure 4, table 4). New York institutions followed with 3,986, then Texas (3,384), Massachusetts (2,591), Pennsylvania (2,463), Illinois (2,362), Florida (2,018), Ohio (1,921), and Michigan (1,599). These nine states accounted for 54% of all doctorates awarded in 2008.
Field of Study
There were 292 fields of specialization into which the SED classified research doctoral degrees in 2008 (listed in the SED questionnaire, appendix B). Because fields of specialization are dynamic entities that reflect the evolving programs of researchers and their constituencies, the SED list is assessed periodically to identify emerging fields and is modified, as needed, to accommodate changes in the world of doctoral education.
Consistent with past practice in presenting the SED data, the fields of specialization are grouped into seven broad fields: life sciences (including agricultural sciences/natural resources, biological/biomedical sciences, and health sciences), physical sciences (including mathematics and computer and information sciences), social sciences (including psychology), engineering, education, humanities, and a heterogeneous group classified as other fields (including business, communication, social work, and theological programs). Detailed data tables 36, 37, and 47 report numbers of doctorate recipients by field of specialization.
The institutions that in 2008 granted the largest numbers of doctorates in each of the seven broad fields are listed in table 3. The Johns Hopkins University led all universities in life sciences (235), the University of California-Berkeley granted the most doctorates in the physical (192) and social sciences (159), and the Georgia Institute of Technology granted the most engineering doctorates (319). Teachers College of Columbia University led all universities in education doctorates awarded (154), Harvard had the highest total in the humanities (138), and the University of Texas-Austin granted the most doctorates in the diverse "other fields" category (70).
The numbers of doctorates awarded in the seven broad fields were also concentrated in a relatively small number of institutions. The 10 institutions that granted the largest number of doctorates awarded 15% of all doctorates in 2008, but the concentration was higher in five of the seven broad fields: 27% in engineering, 22% in humanities, and 18% in life sciences, physical sciences, and other fields (table 3).
The slight overall increase of 1.4% in doctorates awarded between the 2007 and 2008 academic years was a result of increases in five of the seven broad fields: life sciences and social sciences were each up 4%, education and engineering by 2% each, and physical sciences by 1%. The increases in those fields were partially offset by a decrease in humanities (8%) and other fields (2%) (detailed data table 47).
Since 1990 life sciences has been the largest broad field, and 11,088 doctorates were awarded in 2008. Over the 5-year period 2003–08, the number of doctorates awarded in engineering, physical sciences, and life sciences have shown the largest increases: 49%, 39%, and 30%, respectively (table 5). Doctorate completions in education and humanities were slightly lower—just under 1% and 9% fewer degrees awarded, respectively, in 2008 than were awarded 5 years earlier (figures 5, 6; table 5).
Life sciences, physical sciences, social sciences, and engineering—the four broad fields that together constitute "science and engineering" (S&E)—represented 71% of all doctorates awarded in 2008. S&E doctorates accounted for 67% of all doctorates in 1998, 65% of the total in 1988, and 58% in 1978 (table 5).
The 30-year comparisons for all seven broad fields are shown in figure 7. The relative shares of graduates in life sciences, physical sciences, and engineering were greater in 2008 than in 1978, relative shares of graduates in social sciences, humanities, and education were smaller, and relative shares of graduates in other fields in 1978 and 2008 were about the same (figure 7). At the major field level, biological/biomedical sciences (within life sciences), computer and information sciences (within physical sciences), and electrical and related engineering were the fields that showed the greatest increase in their relative share over the past 30 years (5 percentage points for biological sciences, and 3 percentage points for computer and information science and electrical and related engineering). Education research showed the greatest decline in relative share, down 5 percentage points in 2008 as compared with 1978 (table 5).
The numbers of doctorate recipients in the largest subfields within the seven broad fields are shown in table 5. The main fields of growth within life sciences were health sciences, which grew from 512 doctorate recipients in 1978 to 2,094 in 2008, and biological/biomedical sciences, which grew from 3,516 to 7,793. Within these two subfields, the fine fields that increased the most over the past decade are epidemiology, genetics/genomics, and neurosciences.
In physical sciences, the most growth occurred in computer and information sciences, increasing from 121 doctorate recipients in 1978 to 1,786 in 2008. The largest growth in social sciences was in the diverse "other social sciences" subfield. Within this subfield, the fine fields of geography, area/ethnic/cultural/gender studies, and public policy analysis experienced the most growth over the past decade (detailed data table 47).
In the broad field of engineering, electrical and related engineering showed considerable growth. Nearly one-third of the total increase in engineering doctorate recipients from 1978 to 2008 was in this field, which increased from 539 in 1978 to 2,299 in 2008. The subfield of industrial engineering showed the greatest growth during this 30-year period; however, the absolute numbers for this field are still relatively small (281 in 2008).
The numbers of new doctorate recipients increased in two of the three broad non-S&E fields (humanities and other fields); however, there was a decrease in the proportion of the cohort that earned doctoral degrees in humanities. The largest growth in humanities subfields was in "other humanities." The detailed field totals in detailed data table 47 indicate that, over the past decade, the other humanities fields with increasing numbers of doctorate recipients included American/U.S. studies, archaeology, and religion/religious studies. Within other fields, the largest growth was seen in the subfield of business and management, from 713 in 1978 to 1,437 in 2008.
The numbers of doctorates awarded in education dropped over the 30-year period. The only subfield within education that showed growth from 1978 to 2008 was education administration, from 1,455 doctorates to 2,248 (table 5, detailed data table 47).
In 2008, the number of doctorates awarded to men rose by 95 over the previous year, and doctorates awarded to women rose by 612 (figure 8; detailed data tables 49, 50). Women's share of all doctorates earned in 2008 was 46%, similar to that in 2007 (table 6). 2008 was the 13th consecutive year in which the representation of female doctorate recipients has surpassed 40%. Women constituted 45% of all doctorate recipients in 2003, 42% in 1998, and 27% in 1978 (table 6).
The proportion of doctorates earned by women has also grown consistently within all of the broad fields of study. Women constituted over two thirds (67%) of all education doctorate recipients for 2008 and were the majority in social sciences (58%), life sciences (53%), and humanities (52%). The representation of women among doctorate recipients in physical sciences and engineering for 2008 was 28% and 22%, respectively (figure 9). However, these percentages represent significant increases over the last 30 years. In 1978, when 27% of all doctorate recipients were women, 10% of the doctorates in physical sciences and 2% in engineering were awarded to women. Less dramatic but similar long-term trends are discernible in other broad fields as well. Between 1978 and 2008 the proportion of female doctorate recipients increased from 23% to 53% in the life sciences, from 31% to 58% in the social sciences, and from 38% to 52% in humanities fields (figure 9, table 6).
In 2008 women constituted 41% of S&E doctorate recipients and 58% of those earning doctorates in non-S&E fields. Of the major fields that evidenced greater than 60% growth in the proportion of women over the past decade, all were in engineering (table 7). The largest growth in the share of female doctorate recipients from 1998 to 2008 was observed in other engineering (80%), electrical and related engineering (72%), industrial engineering (63%), and aerospace/aeronautical engineering (63%).
Race/Ethnicity of U.S. Citizens and Permanent Residents
A total of 6,981 U.S. citizens and permanent residents who are members of racial/ethnic minority groups were awarded doctorates in 2008, 23% of the U.S. citizens and permanent residents who earned research doctorates and reported race/ethnicity (table 8). (In this report, American Indians, Asians, blacks, Hispanics, Native Hawaiians, and individuals who reported more than one race are considered to be minority racial/ethnic groups). This number is higher than in 2007, when 6,587 minority group members earned research doctorates (22% of the total) (detailed data table 48).
Among U.S. citizens and permanent residents who reported race/ethnicity, Asians earned the most doctorates (2,543) of the minority groups in 2008, followed by blacks (2,030), Hispanics (1,765), persons of multiple race (520), American Indians (123), and Native Hawaiians (96). A total of 249 U.S. citizens reported that they were not Hispanic but did not report their racial background in the 2008 survey. These individuals are not counted here as racial/ethnic minorities. They and the Native Hawaiians are grouped in the "other" category and are not shown separately in table 8 or figure 10.
The number of minority doctorate recipients among U.S. citizens and permanent residents in 2008 was 21% higher than the total in 2003 and 19% higher than in 1998. Doctorate production among non-Hispanic whites showed a more modest increase (7%) from 2003 to 2008 and decreased by 4% from 1998 to 2008.
Although rates of change have varied between 1988 and 2008, the historical trend has been growth in the number of doctorates awarded to racial/ethnic minorities throughout the entire 20-year period. The 20-year increases were greater for Hispanics (154%), than for blacks (110%), Asians (106%), and American Indians (31%) (figures 10, 11; table 8).
Minority group members were most highly represented in 2008 in the broad fields of engineering (27% of U.S. citizens and permanent residents earning doctorates), education (26%), and other fields (26%). The lowest percentages of minorities were in humanities (18%) and physical sciences (20%) (figure 12). The proportional representation of the different minority groups varied by broad field. Asians were the largest contingent in engineering, physical sciences, and life sciences, representing 62%, 54%, and 47%, respectively, of all minority group members earning doctorates in those broad fields during the 2008 academic year. Blacks were the largest minority population in education (53%) and other fields (44%), and Hispanics were the largest minority population in social sciences (34%) and humanities (32%). This pattern of relative representation has been consistently observed since 1988, except in the social sciences and other fields (table 8). (See table 9 for the numbers of minority doctorate recipients in each of the 25 subfields in 2008.)
The pattern of growth for the aggregate U.S. citizen and permanent resident minority populations also held for most of the separate minority groups within most of the seven broad fields of study from 1988 to 2008. The general pattern for minority recipients had been one of increases from 1988 to 2008. Within the broad fields of study, however, there were some noteworthy trends. One was that the number of American Indian doctorate recipients fell in every broad field but the life sciences in 2008 relative to 1998. Moreover, increases in black and Hispanic representation within the life sciences have been especially large over the past decade (table 8).
Among U.S. citizens and permanent residents, the balance of male and female doctorate recipients in 2008 varied among racial/ethnic groups. Just over half (51%) of doctorates earned by whites were awarded to women. For the third straight year, women were the majority doctorate recipients in all U.S. citizen and permanent resident minority populations: 64% of blacks, 58% of Hispanics, 59% of American Indians, 55% of Asians, and 55% of multiracial doctorate recipients (figure 13; detailed data tables 48–50).
Table 10 lists the universities that awarded the largest number of doctorates to members of minority racial/ethnic groups between 2004 and 2008 and the number of doctorates granted by each university. Over that interval, five institutions—University of California-Los Angeles, University of California-Berkeley, Stanford University, University of Southern California, and Harvard—awarded a total of 1,860 doctorates to Asians, or 16% of all doctorates awarded by U.S. universities to Asians. Howard University awarded, by far, the most doctorates to blacks (334), followed by Nova Southeastern University (170). These two institutions granted 5% of all the doctorates awarded to blacks over this period. The leading institutions awarding doctorates to Hispanics were the University of Puerto Rico-Rio Piedras, University of California-Los Angeles, University of California-Berkeley, and the University of Texas-Austin. Oklahoma State University awarded the largest number of doctorates to American Indians (30) and University of California-Berkeley awarded the most doctorates to multiracial graduates (88).
The concentration of minority doctorate recipients in certain institutions is noticeably greater than for the doctoral population as a whole. Over the 2004–08 period the 10 universities granting the largest numbers of doctorates to all doctorate recipients conferred 15% of all doctoral degrees. However, over the same time period, the 10 universities that awarded the most doctorates to Asians granted 25% of all Asian doctorates; for blacks the corresponding figure was 16%; for Hispanics it was 21%; for American Indians it was 24%; and for multiracial doctorate recipients it was 22% (table 10).
Each year, the SED gathers information concerning the U.S. citizenship status and country of citizenship of the new doctorate recipients at the time of graduation. Of the 2008 doctorate recipients with known citizenship status (94% of the total), 67% were U.S. citizens or permanent residents (i.e., "green card" holders), and 33% were non-U.S. citizen temporary visa holders (table 11).
The proportion of non-U.S. citizen temporary visa holders earning doctorates from U.S. institutions has increased over time. The 5-year snapshots shown in table 11 indicate that the percentage of new doctorates awarded to individuals on temporary visas rose from 12% of all doctorate recipients who reported citizenship in 1978 to 33% in 2008. The growing numbers of doctorates awarded to foreign students on temporary visas has accounted for the majority of the overall growth in the number of doctorate recipients since 1978.
U.S. citizens and permanent residents earned more than three-fourths of the doctorates awarded in social sciences, education, and humanities (77%, 91%, and 84% of those reporting citizenship status, respectively), as well as about two-thirds of the doctorates awarded in life sciences and other fields (69% and 64%, respectively) in 2008 (table 11). Temporary visa holders earned the majority of doctorates awarded in engineering (60%) and just under one-half (48%) of the doctorates awarded in physical sciences. In absolute numbers, U.S. citizens and permanent residents earned more doctorates in life sciences than in any of the other broad fields, whereas engineering was the most prevalent broad field of degree for those in the United States on temporary visas.
The trend toward increasing female representation in the doctoral cohorts is particularly striking for U.S. citizens and permanent residents. In 2008, 52% of all doctorates awarded to U.S. citizens and permanent residents went to women. This marks the sixth consecutive year in which the majority of U.S. citizens and permanent residents receiving research doctorates were women (detailed data tables 48, 50).
Women holding temporary visas were more concentrated in S&E fields of study than were female U.S. citizens and permanent residents. Women holding temporary visas represented 23% of all female doctorate recipients in 2008, but they earned 28% of the doctorates granted to women in life sciences, 41% of the doctorates earned by women in physical sciences, and 50% of the doctorates earned by women in engineering (detailed data tables 38, 39).
In 2008, 4,526 doctorate recipients were citizens of China (including Hong Kong), representing 10% of the total number of degrees awarded to individuals who reported citizenship (table 12). The lists of top 15 countries in terms of the number of doctorates awarded to non-U.S. citizens were similar in 2007 and 2008, although some rankings changed. Romania and Iran, among the top 15 countries in 2007, were replaced by Italy and Colombia in 2008. The leading five countries (China, India, Korea, Taiwan, and Turkey) accounted for 21% of all doctorates awarded by U.S. universities to individuals of known citizenship in 2008. This list has been relatively stable over the past 10 years, with China, India, Korea and Taiwan making up the top four every year. However, beginning with 2007, Turkey replaced Canada as the fifth largest country, and it maintained that position in 2008. Thirty percent of all 2008 doctorate recipients who reported citizenship were from the 40 nations listed in table 12.
The 20 institutions awarding the largest numbers of doctorates to temporary visa holders in 2008 are listed in table 13. The University of Illinois at Urbana-Champaign awarded the largest number of doctorates to temporary visa holders (374).
Parental Education Background
Since 1963, the SED has asked new doctorate recipients to report their fathers' and mothers' highest level of educational attainment. As was the case in previous Summary Reports, responses are grouped into four categories: high school diploma or less, some college, baccalaureate degree, and advanced degree, including a master's, doctorate, or professional degree.
Doctorate recipients' fathers and mothers differed in educational attainment at the highest and lowest ends of the spectrum but were quite similar in terms of earning a bachelor's degree and completing some college. The 2008 data indicate that 27% of recipients' fathers had earned no more than a high school diploma; the corresponding figure for their mothers was 35% (table 14). Fourteen percent of doctorate recipients had a father who had attended college but did not attain a baccalaureate degree; 17% of the mothers of doctorate recipients in 2008 achieved this level of education. Over one-fourth (26%) of doctorate recipients indicated that their fathers earned a baccalaureate degree; the percentage whose mother earned a baccalaureate degree was also 26%. At the upper end of the parental-education range, over one third (34%) of doctorate recipients' fathers held an advanced degree, compared with the 23% whose mothers had an advanced degree.
Male and female doctorate recipients showed some differences in their parents' educational backgrounds. Female doctorate recipients tended to report higher educational attainment for their mothers than did their male counterparts. Specifically, 24% of women, compared with 22% of men, reported that their mothers attained an advanced degree, whereas 32% of women, compared with 37% of men, reported that their mothers attained no more than a high school diploma. The reported educational backgrounds of fathers differed little between male and female doctorate recipients.
There is considerable variation in parental education attainment by race/ethnicity, citizenship status, and broad field of study. Among U.S. citizens and permanent residents, Asian, white, and multiracial doctorate recipients were more likely than members of other racial/ethnic groups to come from families in which one or both parents attained at least a baccalaureate degree. Black, Hispanic, and American Indian recipients' parents were less likely to have gone beyond high school and were far less likely than parents of white, Asian, and multiracial recipients to have attained a baccalaureate or advanced degree. Doctorate recipients who were U.S. citizens or permanent residents were more likely than those holding temporary visas to report that their mothers attained at least a baccalaureate degree (52% and 41%, respectively). Similarly, U.S. citizens and permanent residents were more likely to report that their fathers attained at least a baccalaureate degree (61%) than were non-U.S. citizens who held a temporary visa (57%).
The distributions of parental education by the broad fields in table 14 reflect, in part, the different racial/ethnic and citizenship compositions of the fields. Doctorate recipients in humanities displayed the highest percentages of both mothers (65%) and fathers (55%) with at least a baccalaureate degree. The lowest percentages of baccalaureate or higher degrees achieved by fathers or mothers were reported by doctorate recipients in the broad field of education (43% for fathers and 35% for mothers). Education also had the highest percentage of parents whose formal education ended at high school or before. The broad field of humanities had the lowest percentage of parents who did not go beyond high school.
Over the past 30 years the overall trend has been toward parents of doctorate recipients being more highly educated (figure 14; table 15). In 1978, 42% of doctorate recipients reported that neither of their parents had attained an education beyond a high school diploma, and about one in five (21%) reported that at least one parent had an advanced degree. By 1993 the proportion of doctorate recipients reporting an advanced degree as highest parental education (33%) surpassed those reporting a high school diploma or less (31%). By 2008 the proportions in the most- and least-educated groups had almost completely reversed, with 21% of doctorate recipients reporting highest parental education of a high school diploma or less and 40% reporting at least one parent with an advanced degree.
Educational History of Doctorate Recipients
The SED collects information about several aspects of doctorate recipients' educational history that, taken together, provide insight into the educational pathways that students take on the way to earning a research doctoral degree. Since the start of the survey in 1957, the SED has collected detailed information about master's and baccalaureate degrees earned by research doctorate recipients. The SED has also collected information pertaining to additional postsecondary degrees earned, as well as community college enrollments. The SED questionnaire was modified in 2004 to improve the coverage of master's degree attainments and to ask about community college participation, and this section draws on the data from those enhancements.
Overall, 73% of all 2008 research doctorate recipients reported earning a master's degree (table 16). However, there is significant variation in reported rates of master's attainment by broad field of doctoral study. Research doctorate recipients in S&E fields were less likely to earn a master's degree than were their counterparts in non-S&E fields. In particular, doctorate recipients in life sciences (51%) and physical sciences (65%) reported attaining a master's degree at lower rates than doctorate recipients in engineering (77%), social sciences (82%), or any of the non-S&E fields: humanities, other fields, and education (85%, 85%, and 89%, respectively).
Men and women attained master's degrees at similar rates (men 72%, women 75%). Temporary visa holders earned master's degrees at a slightly higher rate (80%) than their U.S. citizen and permanent resident counterparts (75%). Among U.S. citizens and permanent residents, master's attainment differed by the doctorate recipients' race/ethnicity (figure 15; table 16). Overall, blacks (84%) and American Indians (83%) reported earning a master's degree at higher rates than reported by multiracial doctorate recipients (75%), whites (75%), and Hispanics (74%). Asians (70%) reported the lowest rate of earning a master's degree. Differences in the racial/ethnic composition of doctorate fields do not appear to fully account for this observed difference in master's attainment. Blacks reported attaining master's degrees at a higher rate than the other racial/ethnic groups in two of the four S&E broad fields—social sciences and engineering—and attained master's degrees at a higher rate than all but American Indians in the life sciences. In the non-S&E fields, there were no major differences in master's attainment by race/ethnicity.
Overall, about 57% of doctorate recipients reported earning a master's degree that was related to their doctoral degree (i.e., in the same major field of study) (table 16). The percentage earning a master's in the same field as the doctorate varied significantly by field of doctoral study. The broad fields of life and physical sciences, with the lowest rates of earning a master's degree, also had the lowest proportion of doctorate recipients who earned a related master's degree—36% and 55%, respectively. At least 60% of doctorate recipients in all other broad fields of study reported earning a related master's degree.
In all of the broad S&E fields of study except social sciences, the percentage of temporary visa holders who reported earning a related master's degree was higher than that of their U.S. citizen and permanent resident counterparts. In social sciences, 70% of U.S. citizens and permanent residents reported earning a related master's degree, compared with 66% of temporary visa holders. Within all of the broad non-S&E fields, U.S. citizens and permanent residents reported earning a related master's degree at a higher rate than their temporary visa holder counterparts (table 16).
Overall, 53% of research doctorate recipients earned their baccalaureate degree in the same major field of study as their doctoral degree. However, this percentage varied by broad field of doctoral study. Within the broad S&E fields, the percentage of doctorate recipients whose baccalaureate field was the same as their doctoral field ranged from a high of 77% of engineering doctorate recipients to a low of 48% of life scientists. Physical sciences and social sciences fell between the two with 62% and 53%, respectively (detailed data tables 38, 39). Among the non-S&E fields, 50% of the doctorate recipients in the humanities reported earning a baccalaureate degree in a related field. Doctorate recipients in other fields (34%) and education (32%) were the least likely among all the broad fields of study to earn a baccalaureate degree in the same major field of study as their doctoral degree (detailed data table 40).
Since 2004 the SED has explicitly asked doctorate recipients if they have ever attended a community or junior college (item A14, appendix B). The responses to this item show that the community college system contributes to the education of a non-trivial proportion of research doctorate recipients in all of the broad fields of doctoral study. Overall, 13% of research doctorate recipients indicated that they had attended a community college at some point in their educational history. This percentage varied by broad field of doctoral study, from a high of 22% of doctorate recipients in education to lows of 9% in physical sciences and 7% in engineering (table 17).U.S. citizens and permanent residents were far more likely than their temporary visa holder counterparts to have attended community college (19% compared with 2%). This relationship held across all broad fields of doctoral study. Among U.S. citizen and permanent resident doctorate recipients, American Indians, multiracial recipients, and Hispanics were more likely to have attended community college (39%, 26%, and 24%, respectively) than were whites, blacks, or Asians (20%, 17%, and 13%, respectively).
Time to Degree
The amount of time needed to complete a doctorate is a key concern for those pursuing the degree, as well as for the faculties and administrations of degree-granting institutions and national public agencies and private organizations that support doctoral study. Time to degree completion is likely to be affected by a number of factors, including individual preferences, economic constraints, labor markets for new doctorate recipients, cultures of the academic disciplines, and institution-specific program characteristics.
The SED measures time to degree three ways: (1) the total time elapsed from completion of the baccalaureate to completion of the doctorate, (2) the total time elapsed from the start of any graduate school to completion of the doctorate, and (3) the age of the doctorate recipient at the time the doctorate is awarded. The median time-to-degree indices vary somewhat by sex, citizenship, and race/ethnicity; however, these differences are generally reflections of the broad field differences.
Baccalaureate to Doctorate
For the 2008 doctorate recipients, the median total time span from baccalaureate to doctorate was 9.4 years (table 18). The median total time span was shortest in physical sciences (7.7 years) and engineering (7.9 years) and longest in education (17.0 years). Large numbers of individuals who earn doctorates in the broad field of education work full time before starting their graduate degree programs and/or continue to work full time while earning their doctorates.
Median total time to degree increased from 1983 to 1993 and has been declining since then. The 2008 median total time to degree was about 8 months shorter than in 2003 and about 13 months shorter than in 1998 (figure 16; table 18). However, in 2008 doctorate recipients in all of the broad fields except engineering had the same or longer time to degree than those in 1983.
Across the whole population of new doctorate recipients, women had longer total times to degree than did men, but the sex differences tend to be smaller, or even reverse, when men and women are compared within specific broad fields (table 19). Similar patterns hold for comparisons of U.S. racial/ethnic groups, and for U.S. citizens and permanent residents versus temporary visa holders.
Graduate School to Doctorate
The median duration between starting and completing graduate school was 7.7 years for recipients of doctorates in 2008 (table 18). Graduate-school time to degree was shortest in physical sciences (6.7 years), engineering (6.7 years), and life sciences (6.9 years) and was longest in education (12.7 years). Like total time to degree, time spent in graduate school increased between 1983 and 1993, has declined overall since then, and varies with broad field of study. Time spent in graduate school was the same or higher in 2008 than in 1983 in life sciences, physical sciences, engineering, and education, but was lower in social sciences, humanities, and other fields (table 18).
Age at Doctorate
A third measure of time to degree gathered in the SED is age at receipt of the doctorate. The median ages of those who earned doctorates in 2008 are shown in detailed data tables 38–40 by major field of degree and in detailed data table 41 by citizenship and race/ethnicity; figure 17 displays their age distribution. The median age at receipt of the doctorate for all doctorate recipients in 2008 was 32.4 years. Like other measures, age at degree varies with field of study. The majority of doctorate recipients in S&E fields earn their degrees while in their early 30s. In comparison, median age at doctorate was 34.9 years in humanities, 41.5 years in education, and 35.6 years in the other fields category (table 20).
Doctorate Recipients with Disabilities
Since 1985 the SED has included questions asking whether the doctorate recipient has a physical or other kind of disability. The current question format (items C10 and C11, appendix B) has been used since 2001 and asks respondents to indicate all applicable response options. Among the 2008 doctorate recipients, a total of 656 individuals (slightly more than 1% of the doctoral cohort) indicated having one or more disabilities (table 21). The most frequently reported disabilities were learning or cognitive disabilities, with 209 doctorate recipients indicating this disability, followed by physical or orthopedic, with 204. Doctorate recipients with disabilities were more likely to earn their degrees in non-S&E fields of study (41%) than were persons who reported no disabilities (30%). Women reported a disability more often than men. U.S. citizens and permanent residents were more likely to report one or more disabilities than were temporary visa holders.
 Doctorates are reported by academic year (from 1 July of one year through 30 June of the following year) and include research doctorates in all fields. Research doctoral programs are oriented toward preparing students to make original intellectual contributions in a field of study and typically entail the completion of a dissertation. Doctoral degrees, such as the PhD, DSc, and research EdD, are covered by this survey; professional degrees (e.g., MD, DDS, DVM, JD, PsyD, DMin) are not. A full list of included degrees is in appendix A. Before 2001, the SED covered only the first research doctorate earned. Since then, the SED has also covered the second research doctorate. In 2008, a total of 109 individuals earned a second research doctorate.
 American Indians or Alaska Natives are referred to as American Indians in this report, blacks or African Americans are referred to as blacks, and Native Hawaiians or Other Pacific Islanders are referred to as Native Hawaiians.
 Following the federal standards established for the 2000 decennial census of the U.S. population, the SED changed the way in which race and ethnicity were requested starting with the 2001 questionnaire. The new format asked respondents to mark one or more racial categories that apply to them, rather than a single category as had been requested since 1974, when race and ethnicity questions were first added to the SED questionnaire. Additional changes included separating Pacific Islanders from Asians and creating a new category, Native Hawaiians or Other Pacific Islanders, and adding a Cuban response option to the Hispanic ethnicity question. The 2008 SED questionnaire is provided in appendix B.
 The decline in the number of doctorate recipients identifying themselves as American Indians on the SED questionnaire may be related in part to the introduction in the 2001 questionnaire of the option to select one or more racial categories. Of the 520 non-Hispanic U.S. citizen and permanent resident respondents indicating more than one race in 2008, 201 selected American Indian/Alaska Native as one of their races. However, there were declines in the number of American Indian doctorate recipients both before (1999–2000) and after (2002–06) the introduction of the revised item; see detailed data table 48.
 Versions prior to the 2005 Summary Report combined the "some college" and "baccalaureate degree" categories into a single category. The Summary Report 2002 included a special section on first-generation college graduates earning research doctorates, which relied on the respondents' reports of their parents' educations.
 Refer to appendix A for details on the aggregation of subfields to determine major field. A related master's degree does not necessarily indicate that the degree was earned as a part of the doctoral program. This report does not differentiate between master's degrees earned as a part of the doctoral program and master's degrees not earned as part of the doctoral program. See item A8 in appendix B for questions pertaining to the master's degree referenced in this report.