A topic of much discussion in many circles relates to appropriate levels for predoctoral and postdoctoral stipends. In order to inform these discussions, I have analyzed historical trends for predoctoral and postdoctoral stipends provided through the National Research Service Award (NRSA) program.
Consider first the predoctoral stipend. In FY1983, this stipend was set at $5292 per year. Based on my personal experience, this was somewhat (although not dramatically) lower than the stipends provided by many Ph.D. programs. Starting in FY1985, NIH began to make a series of adjustments to move this stipend to a level that more closely reflected stipends being provided in graduate programs (and to make these stipends more consistent with the cost of living in many areas). These adjustments continued through 1998 and the beginning the NIH budget doubling, when more substantial corrections were made. At the end of the doubling with the associated nearly flat budgets, no adjustments were made although modest adjustments have been made in recent years. These stipend levels are compared with those derived by inflation adjustment of the FY1983 levels below:
This shows that the stipend increases substantially exceeded inflation based on the FY1983 value. However, as noted above, the base value was relatively low. Based on the FY2013 level, the corresponding level for FY1983, correcting backwards for inflation, would be $9430.
The first-year postdoctoral NRSA stipend for FY1983 was $14040 (more than 2.6 times the predoctoral stipend level). Modest adjustments were made starting in FY1985 until the doubling when more substantial changes were made (e.g. $21000 to $26250 from FY1998 to FY1999). These adjustments continued through the doubling with more modest adjustments over the past decade. The results compared with those based on inflation of the FY1983 are shown below:
Since most predoctoral and postdoctoral stipends are paid from research grants and not from training grants or fellowships (but these NRSA levels are frequently used as guidelines for other stipend levels), a key point of comparison involves changes in the sizes of Research Project Grants (RPGs) over this same time period. In FY1983, the average annual total cost (TDC) for an RPG was $124,080. The RPG average size increased steadily through FY2012 before dropping somewhat in FY2013 (associated with the sequester cut). The RPG cost data are compared with the FY1983 value corrected for inflation or corrected for the BRDPI (Biomedical Research and Development Price Index) below:
The average RPG size increased faster than either inflation or BRDPI over this period. However, a couple of caveats are appropriate. First, while the average size has increased, I do not know how the distribution of grant sizes has changed over this period of time. For example, it could be that the increase in the average size has been driven substantially by increases in the sizes of large grants while the sizes of many grants near the median may not have increased as much. This is a hypothesis that must be investigated further.
The changing stipend levels can be compared with the changing average RPG level by looking at the ratio of the stipend levels to the inflation-corrected value for each year divided by the ratio of the RPG average value to the BRDPI-corrected value as shown below:
This plot confirms that the predoctoral stipend level (corrected for inflation) has grown faster than the level of the RPG average size. In contrast, the postdoctoral stipend did not rise as fast as the average RPG size increased until the increase in the postdoctoral stipend associated with the doubling.
This figure reveals three phases. In the first phase, from approximately 1983 to 1997, the predoctoral stipend grew slightly faster than the average RPG growth while the postdoctoral stipend grew more slowly than the average RPG size.
In the second phase (from 1998 to 2003 (that is, the period of the NIH budget doubling), the growth in the postdoctoral and, particularly, the predoctoral stipend exceeded that for the average RPG size. The predoctoral stipend increased by 70% from $11748 in 1998 to $19968 in 2003 while the postdoctoral stipend increased by 63% from $21000 in 1998 to $34200. Corrected for inflation, these changes amount to 51% for the predoctoral stipend and 44% for the postdoctoral stipend. Over this same period of time, the average RPG size increased from $277700 to $379900, an increase of 37%, or 16% correcting for BRDPI.
The third phase runs from 2004 to the present. During this period, growth in both stipends and average RPG size has been relatively modest. Predoctoral stipends increased by 6% from $20772 to $22032. This is a drop in value of 14% correcting for inflation. The postdoctoral stipend increased from by 10% $35568 to $39264. This is a drop in value of 10% correcting for inflation. Over the same period, the average RPG size increased from $393700 to $444900. This an increase of 13% but a drop in value of 15% correcting for BRDPI. Thus, the balance between stipend levels and RPG size has been approximately maintained but with a slight loss in relative RPG size due to the larger effect of BRDPI versus normal inflation.