Table 3. Different PhD programmes.

	UCSF Tetrad 1999–2001	CSHL Watson school 1999–2006	Average (2009)
Number of students who started PhDs	66	60	16,000
Number (%) who obtained PhDs	63 (94%)	50 (83%)	9,000 (56%)
Average time taken (years)	6.5 (approximately)	4.6	6–7
Post-PhD career path
Research (postdocs included)	56 (89%)	42 (81%)	66%
Related to science (not research)	7 (11%)	7 (13%)	18%
Unrelated to science	0	3 (6%)	13%

A comparison between the Tetrad PhD programme at the University of California, San Francisco (UCSF), the Watson School at the Cold Spring Harbor Laboratory (CSHL) and an average for all PhD programmes shows differences in the proportion of students who obtain PhDs, the average time taken to obtain a PhD, and the proportion of PhDs who remain in research. Some of these differences might be explained by differences in sample sizes and the length of time that has passed since the PhD was obtained. The differences in the proportion of students remaining in research might also be partially explained by UCSF and CSHL recruiting better applicants and/or their reputations helping new PhDs to obtain research positions (rather than being solely due to better training at UCSF and CSHL). Data: UCSF Tetrad: 7 MD–PhD students who started PhDs in this period are not included due to a lack on information on their post-PhD career path. Watson School: Data available at http://www.cshl.edu/images/stories/wsbs/docs/WSBSstats.pdf. Of the ten students who did not obtain PhDs, seven obtained an MS degree. Data for ‘Post-PhD career path’ is for the 52 individuals who obtained PhDs 2002–2008. Average: data from Workforce report, p32.