Research-Doctorate Programs in the Biomedical Sciences: Selected Findings from the NRC Assessment (2011)
Chapter: 4 Time to Degree, Funding, and Completion Rates
Time to Degree, Funding, and Completion Rates
Median time to degree in the biomedical sciences is relatively constant across fields: medians range from 4.88 to 5.73 years for all biomedical science fields with a standard deviation of less than or equal to one year (see Appendix E). There is a “model” for doctoral training. In almost all programs, more than 90 percent of students are fully funded in the first two years, about one-quarter with an institutional fellowship and the rest through either a traineeship or research assistantship. By the third year, almost all students are funded through some combination of research assistantships and traineeships. This funding is available for 6 years of doctoral study, although the source of funding may vary.
Table 4-1 shows the funding patterns in the biomedical sciences compared with the broad fields of engineering and the physical and mathematical sciences. Nearly one-third of students in the biomedical sciences receive funding through external fellowships or traineeships after the first year, as compared with a percentage that is less than one-half as large for engineering and the physical sciences. Since funding for the biomedical sciences comes primarily from the National Institutes of Health, NIH can use its influence to encourage program practices in the biomedical sciences in a way that is not available for other fields in science and engineering, where research assistantships on grants to individual investigators are the dominant avenue for funding doctoral students beyond the first year.
TABLE 4-1 Sources of Funding for Ph.D. Students by Year of Enrollment 2005-2006, by Percent
| YEAR 1 | YEAR 2 | |||||
| Biomedical Sciences | Physical and Mathematical Sciences | Engineering | Biomedical Sciences | Physical and Mathematical Sciences | Engineering | |
| External fellowships or traineeships alone or with institutional support | 25 | 9 | 10 | 33 | 11 | 11 |
| Institutional fellowships and assistantships alone or with institutional support | 34 | 25 | 27 | 18 | 17 | 20 |
| Research assistantships | 22 | 14 | 33 | 33 | 28 | 46 |
| Teaching Assistantships Other or less than full | 12 | 45 | 15 | 12 | 37 | 11 |
| support | 4 | 2 | 4 | 3 | 2 | 4 |
| Unfunded | 2 | 5 | 10 | 2 | 4 | 7 |
| YEAR 3 | YEAR 4 | |||||
| Biomedical Sciences | Physical and Mathematical Sciences | Engineering | Biomedical Sciences | Physical and Mathematical Sciences | Engineering | |
| External fellowships or traineeships alone or with institutional support | 35 | 13 | 11 | 35 | 13 | 10 |
| Institutional fellowships and assistantships alone or with institutional support | 16 | 14 | 18 | 14 | 14 | 17 |
| Research assistantships | 37 | 38 | 49 | 40 | 43 | 51 |
| Teaching Assistantships Other or less than full | 8 | 2 | 10 | 7 | 23 | 8 |
| support | 3 | 2 | 4 | 3 | 2 | 4 |
| Unfunded | 2 | 4 | 7 | 2 | 4 | 8 |
| YEAR 5 | YEAR 6 | |||||
| Biomedical Sciences | Physical and Mathematical Sciences | Engineering | Biomedical Sciences | Physical and Mathematical Sciences | Engineering | |
| External fellowships or traineeships alone or with institutional support | 34 | 12 | 9 | 32 | 11 | 6 |
| Institutional fellowships and assistantships alone or with institutional support | 11 | 14 | 16 | 10 | 12 | 12 |
| Research assistantships | 43 | 47 | 53 | 46 | 48 | 52 |
| Teaching Assistantships | 6 | 20 | 7 | 6 | 18 | 7 |
| Other or less than full support | 4 | 2 | 4 | 4 | 4 | 6 |
| Unfunded | 2 | 4 | 8 | 2 | 7 | 14 |
| YEAR 6+ | ||||||
| Biomedical Sciences | Physical and Mathematical Sciences | Engineering | ||||
| External fellowships or traineeships alone or with institutional support | 26 | 7 | 4 | |||
| Institutional fellowships and assistantships alone or with institutional support | 11 | 9 | 9 | |||
| Research assistantships | 42 | 43 | 40 | |||
| Teaching Assistantships | 6 | 15 | 7 | |||
| Other or less than full support | 7 | 6 | 6 | |||
| Unfunded | 7 | 18 | 31 | |||
In terms of completion rates, the average percent of doctoral students who complete their degrees in 6 years or less ranges from 42 percent in genetics and genomics to 56 percent in pharmacology, toxicology, and environmental health. There is substantial variation among programs, however. For example, in immunology and infectious disease, one university had a completion rate of 100 percent, while another had a completion rate of 25 percent, although both programs average 3.4 doctorates per year. The extent to which this difference is due to variations in admissions policies, retention efforts, funding, or other factors, is impossible to say. Case studies or other detailed analyses would be needed to sort this out. It is noteworthy, however, that immunology and infectious disease programs at both institutions had the same median time to degree for those students who did complete.
As might be expected, a shorter median time to degree is correlated with a higher completion rate. In at least six fields the coefficient is < -0.3:
TABLE 4-2 Correlations Between Median Time to Degree and Average Completion Rate by Field
| Field | Median Time to Degree (years) | Average Completion Rate (%) | Correlation |
| Biochemistry, Biophysics, and Structural Biology | 5.63 | 45.9 | -0.375 |
| Biomedical Engineering and Bioengineering | 5.06 | 46.3 | -0.134 |
| Cell and Developmental Biology | 5.66 | 50.1 | -0.383 |
| Genetics and Genomics | 5.73 | 41.6 | -0.451 |
| Immunology and Infectious Disease | 5.36 | 56.2 | -0.071 |
| Integrated Biological and Biomedical Sciences | 5.62 | 47.4 | -0.362 |
| Microbiology | 5.58 | 47.1 | -0.493 |
| Neuroscience and Neurobiology | 5.68 | 46.2 | -0.464 |
| Nutrition | 4.88 | 55.8 | -0.165 |
| Pharmacology, Toxicology, and Environmental Health | 5.21 | 56.1 | -0.260 |
| Physiology | 5.13 | 50.9 | -0.179 |
