The National Postdoctoral Association defines a postdoctoral scholar (or a postdoc) as “an individual holding a doctoral degree who is engaged in a temporary period of mentored research and/or scholarly training for the purpose of acquiring the professional skills needed to pursue a career path of his or her choosing.”
As the data show, postdocs are more prevalent in most of the top fields receiving NIH funding (genetics, biochemistry, developmental biology, and neuroscience) than in those fields that receive less NIH funding (nursing, public health, and pharmaceutical science). In light of this, the experiences and future paths of postdocs obviously are an essential part of any study of the biomedical research workforce.
As we started delving more deeply into the data, however, it became clear that we lack reliable information about the postdoc population in the US. There are many reasons for this. First and foremost, we do not collect much information about foreign-trained PhDs who come to the US to do a postdoc, and we have no idea how long they stay or how many leave after their training. These foreign-trained postdocs comprise about 2/3 of the total postdoc population. In addition, postdocs have many titles, and some institutions require they change their titles after a certain number of years. That is why the PhD snapshot I presented last week includes a range of numbers, and they are colored red, meaning that we have little confidence in their accuracy.
Again, we had heard anecdotal information suggesting that the postdoc training period has lengthened over time. However, data from the NSF Survey of Doctorate Recipients suggest that most US-trained biomedical PhDs spend fewer than 5 years in postdoctoral positions. Some do remain in postdoc training a lot longer, though. There is some indication those who do the longest postdocs are the ones who go on to tenure-track academic research careers. For example, in the figure below, the age at first non-postdoctoral job (many of which are in industry) has been consistently a year or two lower than the age of obtaining the first tenure-track job. Note that the latest data in this graph (2002-2003) may be underreported due to delays in reporting that result in a lag time bias.
With all that said, what can we glean from the data we have?
First, data in the figure below from the NSF Survey of Graduate Students and Postdoctorates (which includes all sources of support, not just NIH and surveys US degree-granting institutions about their US- and foreign-trained PhDs) show that the vast majority of basic biomedical postdocs are supported on federal research grants, and this number has grown considerably over the past decade. This is perhaps not surprising, as it parallels the growth of basic biomedical graduate students supported on research grants that I showed in the previous post. Similar to the data for graduate students, the numbers of postdocs supported on federal fellowships and traineeships have remained remarkably stable over the same time period. Once again, these data are supported by the NIH-specific data posted on the RePORT website.
As shown below, the other source of postdoc support that has been growing over the last five years is nonfederal support, defined as support from state and local government, institutions, foreign sources, foundations, industry and other private sources.
Combining the average ~6.5 years of PhD training and 4-5 years of postdoctoral research means that it takes approximately 10 years before a person with a biomedical PhD is ready to begin his or her first or post-training job, and even longer if he or she chooses the academic tenure-track research path.
So what does this postdoc have to look forward to?
We looked at earnings potential as one (but by no means the only) attribute of the career path of biomedical PhDs and compared it to other scientific fields and professions. As can be seen in the table below, starting salaries of biomedical PhDs (pooled SDR data in 2008 dollars) are lower than in other fields. However, later in the career stage, 30 years after the PhD, this is no longer the case.
Table 1. Salary Across Broad Fields by Years of Experience
Source: NSF Survey of Doctoral Recipients
A more comprehensive timeline of earnings is shown in the report and on the website, and Paula Stephan, who was on the modeling subcommittee of our working group, has a very interesting discussion of this in her recent book How Economics Shapes Science.
The data I’ve presented in this and my earlier posts, and the information included in the working group report should be of interest to anyone considering a career in the biomedical sciences and those of us responsible for ensuring the availability of a well-trained biomedical research workforce in the future. They are important for making informed decisions about graduate training, sources of federal support, and institutional policies that will attract and retain the best and brightest in biomedical science careers.