How long should a postdoc last ?

It is de facto a requirement these days for aspiring academic scientists, that a number of years be spent on postdoctoral appointments. I have written about the usefulness of the postdoctoral experience before. Two (closely related) questions that I am frequently asked by current or soon-to-be postdocs are: How long should a single postdoctoral appointment last ? and How many years should one spend as a postdoc ?

To a certain extent, the answer to the above two questions depends on the specific field of inquiry, but some general considerations are valid across the board.
First of all, one must be clear on what “postdoctoral appointment” means. It is a term position, that the postdoc (PD), a junior scientist who has completed his/her doctoral degree typically no more than a few years earlier, spends doing research under the supervision of a Principal Investigator (PI), normally a faculty at a university or a permanent member of the research staff at a national laboratory. Salary, benefits, as well as the degree of intellectual freedom enjoyed by the postdoc can vary (even significantly), but the most important aspect of the position is that it is non-permanent.

There are cases when the institution hosting the PD will be willing to extend the duration of a term appointment (in some cases essentially indefinitely), as long as the PDs themselves or their PIs are willing and able to obtain the funding required to prolong it. Alternatively, the position may be extended as a PD is employed part-time by the hosting institution for purposes other than those for which the person was initially hired, independently of the PI [0],[1].
Because the specific terms of postdoctoral appointments can vary so much, often times a non-permanent, term position for which benefits are significantly better than average will be re-labeled to make it sound more “official” than it is (e.g., “research associate”, “staff scientist” or something along these lines). It is important to be clear on one thing: these are rarely more than cosmetic, “feel-good” type changes, aimed at providing some formal reassurance to the PD — the bottom line, in the eyes of those who will evaluate the curriculum vitae of a PD for hiring purposes, is that this person spent that time in a non-permanent setting.

Why do I insist on the ‘non-permanent’ aspect ?
Because most of us aspire at a permanent employment. Nobody (well, almost nobody) likes the uncertainty, stress and sense of precariousness associated with a term position; therefore, the general perception is that anyone spending what could be regarded as too long a time on a term position, likely did so out of inability to secure a permanent appointment. In turn, such perceived inability will often negatively affect the strength of one’s candidacy for a potentially permanent (e.g., tenure-track faculty) position.
Is this fair ? Of course not (since when is life fair anyway). There are many reasons, both professional as well as personal, which may induce someone to remain on a term appointment rather than seeking a permanent position [2]. However, very few search committee members will be willing to investigate such reasons, and one will be more likely branded as “good, but maybe not excellent”, “possibly a problematic individual”, “not quite faculty material”.
Thus, extending the duration of one’s postdoctoral appointment beyond what is commonly regarded as the average in that field (I come to that in a moment), while clearly providing relief in the short term, will almost never be a good thing for one’s professional future. Not only will it make the PD less palatable at institutions other than the one where (s)he is employed, it will also make it far less likely that that very institution may consider the person for permanent employment (something that happens seldom, but is not unheard of), should an appropriate hiring opportunity arise [3].

Based on my experience and observation, these are my rules of thumb for Physics PDs, assuming that the goal is that of strengthening one’s CV in light of competing credibly for faculty appointments, or permanent staff positions at national laboratories:
1) No more than three years at the same place
2) No more than five years as a PD altogether [4].
I think that, give or take one year, the above is probably valid across all scientific fields. To be a PD for longer than that, in all likelihood means reducing one’s chances of getting that coveted academic/science job, in the process being taken advantage of, putting one’s life on hold, and being disappointed and embittered in the end.


[0] For example, a PD may end up taking on teaching assignments at a university, or technical tasks such as computer administration. In many cases, the person performs an important, mission-critical task at a fraction of the cost of hiring a full-time person for the same task, resulting in a significant save of money for the institution.

[1] A common expression in the community, to describe positions of this type is soft-money position.

[2] A chief example is provided by the the well-known two-body problem.

[3] Those hoping, for instance, that since they have spent a number of years as (glorified) PDs doing research and teaching at the same university department, in the process proving themselves competent, conscientious and hard-working, will have an edge over other applicants for a tenure-track faculty position in that very department, are simply deluding themselves.
It is simple economics: Why waste a faculty or permanent position to hire someone who is already there, has been (and likely still is) willing to work on a lesser appointment, and is apparently uninterested or unable to find a permanent job anywhere else ? Much better to use the position to bring in another person.

[4] In the interest of full disclosure: I did five years as a PD, my first post-doctoral appointment lasted three, and as I was interviewing for faculty jobs in my fifth year I was contemplating industry jobs. I interviewed with a bank, as well as with (gasp) these people too, and was seriously considering a career change (in the financial sector), should, my job search have failed.

Tags: , , , ,

15 Responses to “How long should a postdoc last ?”

  1. Arlenna Says:

    For chemistry it’s usually 1-2 years average, 3 yrs max. But biologists seem to routinely go for 5-7 years. I did 5 years and it did me good, because my PhD was only 3 years long. But that perceived part is true: too long and people look like something is wrong…

  2. pinus Says:

    biomed. postdocs seem to be from 4-8 years.

    I used to think that people who got tenure track jobs did so early (4 years or less)…but recently, I have met a number of people who did 8 or so year post-docs before getting a faculty position. Of course…the last few years of the post-doc has a different name (research instructor…research assistant prof.)

  3. Professor in Training Says:

    Physiology/biomed is usually 3+ years but I think that’s also got a lot to do with how long it takes to get studies up and running. I knew that a faculty position was what I wanted and only stayed as a postdoc for as short a time as possible (just under 4 years). I’ve worked with several people whose postdocs have gone on forever because they were heading down the research associate path which, in a lot of places, is the staff equivalent of a postdoc position.

  4. El Charro Says:

    Here’s a question: Say you want to go to the industry after your PhD, is doing a post-doc a good idea then? and if so, should it be just as long or shorter?

    • Massimo Says:

      In my opinion it depends on the type of industry job you are seeking but I think a PD is always a valid experience. There was a time when one could even do the PD itself in industry — now, at least in physics, I do not think it happens anymore. Still, I think it is a good idea to pick for one’s PD a research group based at a university or national lab but with well-established ties to industry, with a history of placing its own PDs in specific firms.
      PhD advisors are the best resource to identify these groups. I think one 2-yr postdoc should be sufficient in this case.

  5. postdoc Says:

    So does this mean that if you spend > 5 yrs doing postdocs you’re screwed and should find a new career? The job market is scary. I was also wondering this. Does it look bad if you apply every single year that you are a postdoc. There are pluses (increase your chances since it is a game of small numbers) and minuses (it might look bad, it takes a lot of time away from research) to this strategy. I know you took a job at a second tier university and got something better later. But I wonder if one might have better chances at landing a good job if you continue to do postdocs at good places with good people and, of course, be productive.

    • Massimo Says:

      So does this mean that if you spend > 5 yrs doing postdocs you’re screwed and should find a new career ?

      Yes, in my opinion the likelihood of landing a faculty job is a rapidly decreasing function of n, the number of postdoctoral years, for n greater than 4. So, if I were to advise someone asking me where to put a cut-off, I would say at n=5. Of course, nobody can predict the future, and I do know people who became tenure-track faculty after doing close to ten years of postdoc. But I think that past the 5-yr mark, odds are really very very very slim. Just my opinion, of course — that is what a blog is for.

      I wonder if one might have better chances at landing a good job if you continue to do postdocs at good places with good people and, of course, be productive.

      In my opinion, no. The negative effect of someone having been a PD for such a long time will dwarf anything good that may have come out, research-wise, in the overwhelming majority of cases. There will be younger colleagues who will be branded as “more promising” simply because they are largely unproven. The more you are proven, the more people know what your limits are. Being unproven, paradoxically, plays in one’s favour in this field.

  6. transientreporter Says:

    “Research Associate” is dodgy nonsense. PI’s selling them bill o’ goods should be ashamed of themselves.

  7. Cath@VWXYNot? Says:

    Most of the “research associates” I know were given the title in order to facilitate immigration procedures.

    • Massimo Says:

      Well, yes Cath, sometimes that is the case but I think more often one is simply talking a minor upgrade of the position, aimed at making the person “feel good” and perhaps for internal bureaucratic reasons. For example, this may be done to comply with university regulations that prevent a PI from employing a person as a “postdoc” for longer than a certain number of years (at Alberta we do have such a rule).

    • Schlupp Says:

      At Nothing Special State, we all were “postdoctoral research associates”, the “glorified postdocs” were something else without “associate” in it . Our designation was definitely a better wording than “postdoctoral student”, but still just words, of course.

  8. Professor in Training Says:

    A lot of the research associates I know are PhDs who don’t want to be PIs but, yes, there are a couple who were shunted to that title for immigration reasons.

    • Massimo Says:

      A lot of the research associates I know are PhDs who don’t want to be PIs

      And that is exactly how they will be perceived by search committees going through their applications.

  9. R Says:

    Have any of you seen a postdoc of less than a year? Is that possible? (e.g. for a semester)

    • Massimo Says:

      It depends on what you are willing to call “postdoc”. It is always possible to hire someone hourly. Is it a good deal ? I don’t know, if it is just to bridge some kind of funding gap between the completion of one’s position and the start of the next one, I suppose it can be acceptable. I see that all the time.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: