Fig. S1.

This figure shows the age variation of R01 grantees, basic-science PIs, and clinical-science PIs. The average age of first-time (FIR) R01 grantees (15) is shown as a black dotted line. As discussed in Fig. 1, the FIR age is about 6 y older than the threshold age of the 5% youngest. We consider three threshold ages: the 5% oldest (the threshold age of the older 5%); the median age; and the 5% youngest (the threshold age of the younger 5%). In the 34 y from 1980 to 2014, the ages of the oldest 5% of R01 grantees, clinical-science PIs, and basic-science PIs showed changes of 11.3, 7.7, and 9.0 y, respectively. Corresponding changes for the median age are 10.5, 7.1, and 10.3 y, and for the ages of the youngest 5%, they are 6.1, 2.9, and 4.9 y. For the oldest 5% and the median age, basic scientists are always older than clinical scientists, who themselves are older than R01 grantees. For the youngest 5%, since 1989 R01 grantees have been older than either basic- or clinical-science PIs.