At early time points, the two functions are very similar: K doesn’t have much impact on the rate of growth in the logistic function early in time, and growth is mainly limited by r (the replication rate). This is called “r-limited” growth. However, later in time, the resource limitations start impacting the rate of growth in the logistic function, and the population size asymptotes at K. This is called “K-limited” growth. It’s much nicer to live in a period of r-limited growth, when there are plenty of resources. When growth is K-limited, this means that the organisms in the population have so few resources that they die before they can reproduce, or are so hungry they can’t reproduce, or their offspring are so hungry they can’t survive, etc. Not a very pleasant life.
In academia, r-limited growth means that jobs are plentiful, and the main limitations on growth are the number of students per lab and the rate at which they complete their degrees. By contrast, K-limited growth basically means that a faculty member needs to die or retire before a new PhD can get a position, and only a small fraction of new PhDs will ever get tenure-track jobs and start producing their own students. This also means that the competition for tenure-track jobs and research grants will be fierce. Sound familiar?
In the context of academia, K represents the maximum number of faculty positions that can be supported by the society. The maximum number of faculty positions might increase gradually over time, as the overall population size increases or as a society becomes wealthier. However, there is no way we can sustain an exponential growth forever (especially if that means we need over a million positions by 2048 in a field that has only a thousand positions in 2018).
I think it’s pretty clear that we’re now in a K-limited period, where the number of positions is increasing far too slowly to keep up with the demand for positions from people getting PhDs. When I was on the job market in the early 1990s, there were already more people with PhDs than available faculty positions. However, the problem of an oversupply of PhDs was partially masked by an increase in the availability of postdoc positions. Also, it was becoming more common for faculty at “second-tier” universities to conduct and publish research, so the actual number of positions that combined research and teaching was increasing. But this balloon has stretched about as far as it can, and highly qualified young scholars are now having trouble getting the kind of position they are seeking (and we’re seeing 200+ applicants for a single position in our department).
In addition to a limited number of tenure-track faculty positions, we have a limited amount of grant money. In some departments and subfields, getting a major grant is required for getting tenure. Even if this isn’t a formal requirement, the resources provided by a grant (e.g., funding for grad students and postdocs) may be essential for an assistant professor to be sufficiently productive to receive tenure. But an increase in grant funding without a commensurate increase in permanent positions can actually make things worse rather than better. We saw that when the NIH budget was doubled between 1994 and 2003. This led to an increase in funding for grad students and postdocs (leading to the balloon I mentioned earlier). However, without an increase in the number of tenure-track faculty positions, there was nowhere for these people to go when they finished their training. Their CVs were more impressive, but this just increased the expectations of search committees. Also, a lot of the increased NIH funding was absorbed by senior faculty (like me) who now had 2, 3, or even 4 grants instead of just 1. As usual, the rich got richer.
One might argue that competition is good, because it means that only the very best people get tenure-track positions and grants. And I would be the first person to agree that competition can help inspire people to be as creative and productive as possible. However, the current state of hypercompetition clearly has a dark side. Some people write tons of grants, often with little thought, in the hopes of getting lucky. This can lead to poorly-conceived projects, and it can leave people with little time to think about and actually conduct high-quality research. And it can lead to p-hacking and other questionable research practices, or even outright fraud. I think we’re way beyond the point at which the level of competition is beneficial.
Now let’s talk about solutions. Should we increase the number of tenure-track faculty positions at research universities? I would argue that any solution of this nature is doomed to failure in the long run. Increasing the number of position is an increase in K, and this just postpones the point at which the job market becomes saturated. It would certainly help the people who are seeking a position now, but the problem will come back eventually. There just isn’t a way for the number of positions to increase exponentially forever.
We could also try to limit the number of students we accept into PhD programs. This would be equivalent to decreasing r, the rate of “reproduction.” However, for this to fully solve the problem, we would need the “birth rate” (number of new PhDs per year in a field) to equal the “death rate” (the number of retirements per year in the field). Here’s another way to look at it: if the number of positions in a field remains constant, a given faculty member can expect to place only a single student in a tenure-track position over the course of the faculty member’s entire career. Is it realistic to restrict the number of PhD students so that faculty can have only one student per career? Or even one per decade? Probably not.
I have only one realistic idea for a solution, which is to create more good positions for PhDs that don’t involve “reproduction” (i.e., training PhD students). For example, if there were good positions outside of academia for a large number of PhDs, this would reduce the demand for tenure-track positions and decrease r, the rate of reproduction (assuming that there would be fewer people “spawning” new students as a result). Tenure-track positions at teaching-oriented institutions have the same effect (as long as these institutions don’t decide to start granting PhDs). I don’t think it’s realistic to increase the number of these teaching-oriented positions (except insofar as they increase with overall changes in population size). However, in many areas of the mind and brain sciences, it appears that the availability of industry positions could increase substantially. Indeed, we are already seeing many of our students and postdocs take jobs at places like Google and Netflix.
Many faculty in research-oriented universities think that success in graduate school means getting a tenure-track faculty position in a research-oriented university. However, if I’m right that the current K-limited growth curve—and the associated hypercompetition—is a major problem, then we should place a much higher value on industry and teaching positions. The availability of these positions will mean that we can continue to have lots of bright graduate students in our labs without dooming them to work as Uber drivers after they get their PhDs. And teaching positions are intrinsically valuable: A great teacher can have a tremendous positive impact on thousands of students over the course of a career.
This doesn’t mean that we should focus our students’ training on teaching skills and data science skills, especially when these are not our own areas of expertise. Excellent research training will be important for both industry positions and teaching-oriented faculty positions. But we should encourage our students to think about getting some significant training in teaching and/or data science, which will be important even if they take positions in research-oriented universities. And we should encourage some of our students to take industry internships and get teaching experience. But mostly we should avoid sending the implicit or explicit message to our students that they are failures if they don’t pursue tenure-track research university positions. If, as a field, we increase the number of our PhDs who take positions outside of research universities, this will make life better for everyone
