Unsolicited Advice, Part Nine: Choosing a Postdoc

By Sean Carroll | January 8, 2009 1:12 pm

Early January, and time for another entry in our unsolicited advice series — this one on choosing a postdoc. For non-academics, a “postdoc” is that lovely several-year period in between getting a Ph.D. and (hopefully) landing a faculty job, during which one establishes some independence and concentrates on doing research to the exclusion of all the other delicious aspects of professordom. And for reasons that have never been fully explained, a lot of postdoc jobs are offered and accepted in December/January/February, even if they don’t start until September. So now is the time to make yet another one of those choices that will dramatically affect the entire rest of your life.

Here, we’re not telling you how to get a postdoc; we’re presuming you already have more than one offer in hand, and need to choose between them. (Yay you!) At some point we should write about applying for postdocs, but that season is largely passed. Note that postdoc situations vary wildly from field to field, and my experience is largely in theoretical physics; there is more advice at Dr. Isis’s place, and I’m sure elsewhere — as usual, leave links in the comments. Free advice on the internet is worth what you pay for it, but if you get a variety of different perspectives a nugget of wisdom might sneak through.

To decide which postdoc position is right for you, it makes sense to think about what your goals are in being a postdoc in the first place. Generally they look something like this:

1) Do some good science.

2) Learn new things and grow as a scientist.

3) Put yourself in a good position to land a faculty job.

The very good news is that these goals are not in conflict! You can do good science while learning new things, and you can do both of those while positioning yourself to apply for faculty jobs. Indeed, you’ll be in much better position (obviously) if you have done some good science. However, it’s possible to do some good science and nevertheless end up in not such a good position.

Before we unpack that, we should say a word about other considerations. You might care about geographic location, or proximity to a loved one, or easy access to jazz or martinis or gambling or whatever your favorite vice may be. (Personally, I can’t decide.) I’m all about the other considerations, and would never tell you to discount them. Life is short, and the years you spend as a postdoc are just as truly years of your life as any other years. However … if you were thinking that it would be worthwhile, at some point in your life, to sacrifice on your other considerations for a bit in order to concentrate on doing the best science you can — now is the time! Of all the hurdles and bottlenecks along an academic career path, the jump from postdoc to faculty is probably the hardest, just in terms of raw probabilities. (There are a lot fewer faculty jobs than there are postdocs looking for them.) At the same time, the transition from the comforting embrace of graduate school, where (at least in principle) you have an advisor looking over you, to the naked Hobbesian individualism of being a postdoc, where your personal initiative counts for everything, can benefit from a certain amount of increased focus. I know, “comforting embrace” isn’t the first phrase that comes to mind when you think of graduate school. But there is more structure there, and a sense of belonging to something bigger. (Often, as a postdoc, the department won’t even list you in any sort of directory.) So, while there’s nothing wrong with taking other considerations seriously, this temporary phase of your academic trajectory is arguably the best time to put those on the back burner while you concentrate on your job, hoping that sacrifice will pay off later. How much you balance those competing considerations is up to you.

(The extent to which personal initiative counts varies wildly from academic field to field; in a big lab, the role of a postdoc may be little different from that of an advanced grad student. For theorists, the role of a postdoc is little different from that of a beginning professor — you are expected to come up with your own ideas and carry them to fruition.)

With all that throat-clearing out of the way, let’s tackle those above goals. First, you want to choose a postdoc position that will help you do good science. This criterion is actually relatively straightforward, but there are some subtleties. Of course it will help if you go to a place that is chock full of good scientists doing the kind of science you would like to be doing yourself. But you still have to ask some of the same kind of questions you asked when choosing a grad school — at the most basic level, would you yourself be able to productively work with these people? Do you like them, are they supportive? What do the other postdocs who are currently there — or even better, were there recently and have moved on — think about the experience?

Here is an excellent little diagnostic. Of the different places you are considering, have a look at some of the papers they have written over the last three years. Now ask yourself: which of those papers would I have been most pleased to be a co-author on? That’s a direct way of separating vague feelings that “this place is good” from “they are doing what I want to do.” But then, to kick it up a notch, look again at those papers, and in particular at the author lists. Are there any postdocs there? Is this the kind of place where the postdocs collaborate frequently and directly with the faculty and each other, or are they more on their own, or have they still collaborating with their old groups from grad school? Different departments have different personalities, but the evidence of how postdocs generally fit in should be easy to gather.

Next, you want to learn and grow as a scientist. This one is a bit trickier. You definitely do want to grow — it’s unlikely that, as a grad student, you did enough different kinds of work that you would be happy to stay confined within those disciplinary boundaries for the rest of your life. Your postdoc years are a great chance to define yourself (see below), so you should think long and hard about how you want to be defined. On the other hand, it is possible to grow too much. If your degree is in string theory, and your first postdoc is in molecular biology, and your second postdoc is in inorganic chemistry, you’re sort of just being incoherent. You’ll have fun along the way — and if that’s your goal, that’s great — but if you are planning on moving to the next level, you want to be broad without losing coherence entirely. You want to challenge yourself with new things, but you want to challenge yourself productively. You certainly don’t want to think of your postdoc as another round of grad school, where you start from scratch. You are now a professional scientist with some established expertise, and you would like to build on that expertise.

But at the same time — and here’s the crucially important part — you don’t want to just repeat yourself. That’s why everyone always tells you to go somewhere else for your postdoc, not to stick around the same place you were a grad student. It sounds like good, solid advice, but when the moment of decision comes, far too many people choose to play it safe, and either stay where they are (if that option is available) or move over to some group with whom they were already collaborating. It’s hard to appreciate until you’ve been around the block a few times, but different departments are truly different in their approach to doing science. One of the absolute best features of the postdoc system (and there are a lot of crappy features) is that you get an invaluable opportunity to be exposed to the idiosyncrasies and habits of mind of a completely different set of senior researchers. That can be a truly eye-opening experience, and you should try as hard as you can to take advantage. Find people with whom you can work and be productive (you want to write papers, not just take classes or sit at the feet of masters), but who will challenge your preconceptions and open your eyes to new ways of thinking about your field.

Finally we have the money goal: you’d like to put yourself in good position to land a faculty job. (That’s what we’re assuming, anyway; if not, standard disclaimers apply.) Of course this is as much art as science, and there’s a tremendous amount of noise in the system — but you control what you can.

With that in mind, recall that our advice for being a good grad student was to “Be the kind of grad student that people would like to hire as a postdoc.” Guess what? As a postdoc, you will strive to be the kind of postdoc that people would like to hire as an assistant professor. And what kind is that? If you’re honest with yourself, you can probably hit upon the right answer by contemplating the kind of applicant you would be most likely to hire, if you were already a faculty member sitting on a hiring committee. The basic rule is that you’re not going to get hired as a faculty member by being talented and smart; you’re going to be hired because the department sees that you are doing awesome things. When people hire postdocs, the applicants are still charmingly unformed as mature scientists, and their letters of recommendation will often weigh more than their lists of publications. But when it comes to hiring a faculty member, it’s rarely done purely on promise — they want to see that you’ve done something.

So when you’re choosing which postdoc to take, choose the one that maximizes your chances of actually doing something. Writing papers, and (more importantly) writing good papers. And (most importantly) by “good” we do not mean “technically competent.” We mean interesting, even to people outside your immediate circle of friends. Papers you would want to read, even if you hadn’t written them. Those are the kinds of papers you want to be writing as a grad student.

The need to write interesting papers should be obvious, but sometimes it gets lost in the excitement. Writing papers as a grad student can be like having sex as a teenager — you’re amazed that it’s happening at all, and not so concerned with excelling. But at some point, as you mature, it becomes important to do it well. It is deadly, as a postdoc, to fall into the trap of writing papers just because you can write them. Like it or not, there are many people like you competing for a scarce resource in the form of faculty jobs. You have to distinguish yourself. If you are working within any field where there is a nontrivial chance of getting hired as a faculty member, there will certainly be other people writing papers in the same field. What is it that will make your papers better?

And it’s not only good papers — it’s papers that define who you are. That’s a question you will literally be asked when you are applying for faculty jobs — what are you really? What do you do? And the appropriate answer has to be well-defined (like it or not) in terms that are comprehensible to a faculty hiring committee. “I work on models of dark energy” is a bit narrow; “I am a theoretical physicist” is a bit broad; “I work on field theory and particle physics applied to cosmology” is about right. (You can always, and in fact should, continue to broaden your scope all throughout your career.) But you can’t just proclaim it; your list of publications has to proclaim it for you. You won’t want to work on the same thing over and over again, but you do want the work you do to tell a coherent story. Each paper is a dot on a map of possible problems one could be thinking about, and you want your set of dots to form a sensible picture. A postdoc period is a good time to fill in what you might think of as gaps in your toolbox, if you will excuse a terribly mixed metaphor. Become the scientist you would want to hire.

Figure all that out, and then choose the postdoc position that will maximize your chance of writing the papers that make it happen. Easier said than done, I know. If it were easy, it wouldn’t be any fun, would it?

  • http://lablemminglounge.blogspot.com/ Lab Lemming

    “Writing papers, and (more importantly) writing good papers. And (most importantly) by “good” we do not mean “technically competent.” We mean interesting, even to people outside your immediate circle of friends.”

    Is the distinction between interesting and technically outstanding papers an “or” or an “and” comparison?

    (queue whole “Nature as science fiction magazine” debate here)

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    It would be hard to write an interesting paper that was technically incompetent. An amazing result isn’t all that interesting if it’s just wrong. But it’s certainly possible to write an interesting paper that doesn’t show one’s technical chops to best advantage, just because it’s not appropriate in that context.

    Technical brilliance is positively correlated with writing a good paper, but they’re not the same.

  • Big Vlad

    a faculty member in my PhD institution once told me that to get a faculty job one must churn out 4-5 decent papers a year for about 5-6 years. I’ve just started my first postdoc, and I’m enjoying it, but the pressure to publish is a pain in the arse. The word “churning” doesn’t conjure up Sean’s image of learning new things and growing as a scientist….

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Well, 4-5 “decent” papers are not as good as 1-2 groundbreaking papers. But they are better than 1-2 “decent” papers.

    It’s wrong to think that there is pressure to publish lots of papers; but it’s completely correct to think that there is pressure to demonstrate that you are a better scientist than the other people who will be applying for the same jobs down the road. There is more than one way to demonstrate that, but publishing lots of papers doesn’t hurt, all else being equal.

    And why should it? If you were on a hiring committee, and you were faced with two applicants, one of whom published 5 papers per year, and the other published 2 papers per year, and the individual papers were indistinguishable in quality, who would you hire?

    The more interesting case is when you compare two high-quality papers per year to 5 medium-quality papers per year. In that case, different committees will move in different directions, in part because “quality” is not always so easy to discern.

    The postdoc years can be a lot of stress, there is no question. Many people chasing few positions make that inevitable, whatever the eventual criteria for success may be.

  • http://www.yisongyue.com Yisong

    I am a Ph.D. Student in Computer Science. Every year, my department invites on the order of 10 candidates to give job talks and on-site interviews (sometimes with students). In the end, maybe 1-5 will get offers (variance seems pretty high).

    10 seems an incredibly small number considering the number of potential applicants. So it’s often a very good idea to attend conferences and establish relationships with researchers from other institutions. It can give you an enormous advantage in being selected for on-site interviews.

    I wonder if the process is similar in your field. Your post emphasized the need to do good research, but didn’t really touch on the need to communicate said research.

  • Ben Button

    “I wonder if the process is similar in your field. Your post emphasized the need to do good research, but didn’t really touch on the need to communicate said research.”

    It is *extremely* important to attend conferences and to use the opportunity to suck up to important people. This is one of the most depressing and demoralizing aspect of being a postdoc, or indeed being
    an academic. But the fact remains. In fact, this is how you distinguish
    a serious researcher from an academic administrator/department head: the former believes that you should attend conferences only if you think it helps you to write papers, while the latter believes the reverse.

  • Ben Button

    “If it were easy, it wouldn’t be any fun, would it?”

    Actually, it would.

  • Supernova

    I’d like to point out another assumption in the above: that one is aiming for a tenure-track job at a research university. Smaller and/or liberal-arts-type schools typically don’t require one to “churn out” quite so many papers as a postdoc, and they typically want to see at least some evidence of teaching aptitude (or at least informed interest). Which isn’t to say that doing excellent research isn’t important for these types of schools — of course they will also, in general, be more interested in someone with an outstanding research record than someone with a mediocre one. But your postdoc decision may also depend fairly heavily on what flavor of tenure-track job you are eventually aiming for.

  • ts

    It is a good advice, but there is nothing new that people who are about to become postdocs do not know, I think. Not surprisingly it is the execution that is very difficult. I don’t envy those who have to go through the intense competitions against the other brightest minds in maths and theoretical physics, but for those in less intellectually intense fields (i.e., something that you can get away with a lower innate “IQ”) there tend to be more qualified people against whom to compete which introduces more stochastic elements in the process. Navigating through that crap is certainly necessary but absolutely no fun, I must say.

  • http://lablemminglounge.blogspot.com/ Lab Lemming

    “It would be hard to write an interesting paper that was technically incompetent. An amazing result isn’t all that interesting if it’s just wrong.”

    If it takes the rest of the world 20 years to figure out that it’s wrong, then from a career point of view, it is just as useful as a right one.

    I’ll try explaining what I meant in a blog when I get the chance.

  • http://sarahaskew.wordpress.com Sarah

    Great advice. I moved to a country and institution I didn’t know from Adam (although I did speak the language, that helps) after being in the same place for 9 years – and it’s been a great experience. Like you say, the difference between departments and faculties can be huge – and it’s really given me a lot of perspective on the way science gets done.

    Sean – in my experience it’s nearly always the number of papers that counts, with quality being of secondary interest. It angers me a bit, because it almost forces everyone else to focus more on quantity rather than quality. I guess it’s a consequence of the way research departments themselves get assessed.

  • TomC

    One criterion that might help separate the prospective postdoc rank her sheaf of offers: Does the institution/department in question have both theorists and experimenters/observers working in the field of interest, and do they talk to one another? An easy way to increase both the number and the potential interesting-ness of the papers on your c.v. is to get in on a data or projection paper for an experiment/observation (if you’re a theorist), or to lend your nuts-and-bolts wisdom to a wacky theorist’s idea of what to look for (if you’re an experimenter/observer), and this is most easily done if these two types of people are often in the same lunchroom or coffee lounge.

    I’ve also personally found that senior types that tend to be on hiring committees find these cross-pollinations particularly interesting.

  • TomC

    Damn, please ignore the word “separate” in that first sentence.

  • http://www.scienceblogs.com/isisthescientist Isis the Scientist

    This is great advice, per the usual. I think key among things to look for in a postdoc is not just a lab where you will be able to liearn techniques, but the opportunity to think about new questions with the guidance of someone who is willing to help you along the path to independence.

  • amused

    “But when it comes to hiring a faculty member, it’s rarely done purely on promise — they want to see that you’ve done something.”

    Hahahahahahaha! No. Tell the young’uns the truth, Sean.

    When choosing a postdoc, to maximize chances for a future faculty position, you must, I repeat *must*, choose the institution with the greatest perceived prestige and which will give the maximum opportunity to get your names on the papers of famous, influential people. Then, when you get there, forget silly notions about establishing independence etc and devote all your efforts to attaching yourself to the research program(s) of bigshots, being junior co-author on their papers, getting them to like you and think of you as continuing their academic lineage.
    If you don’t do that, then when applying for faculty positions you will join the queue behind those who did.

    For a description of the postdoc life, with discussions of the challenges and strategies for advancement etc, I strongly recommend “My life as a quant: reflections on physics and finance” by Emanuel Derman. He discusses there how his fellow postdocs would cling to the elite institutions, even to the point of turning down paid postdoc positions at a lesser institution to work without salary at an elite one. Now why would they do that do you think?

    Wanting to develop your own independent research program is admirable and all, but you mustn’t even think about that until you have tenure somewhere. Until then it is imperative to remain attached limpet-like to the research programs of the influential people who will be making or breaking you.

    Let’s wind up Sean with a rhetorical question: In general, what will count for more when someone is being assessed for a faculty position:
    (a) Single-author publications in PRL
    (b) Junior co-authorships on routine papers of bigshots (along with lots of other co-authors)
    (Hint: one of these will count for nothing; the other will count for a whole lot.)

    As for my own experience: Only once was I in the fortunate position of having more than one postdoc offer to choose from. There were two:

    (1) A 3-year offer from a very good youngish physicist with interests closely related to mine, who knew of and seemed to have a bit of respect for my work, was interested both in supporting it and interacting with me.

    (2) An offer from a new assistant prof working on different stuff. He didn’t know or care much about my work, but was looking for someone willing to come and work for him on his project for one year, which was all he could afford to pay for from the money remaining in his startup grant. The hiree was supposed to take care of certain time-consuming but mundane aspects of the project, to free up time for the prof to focus on the interesting stuff. And if I wanted to continue my own stuff it would have to be as a hobby in my own time.

    Sounds like an easy decision? You bet it was. Of course, I have omitted the crucial details: The first offer was at a lower tier institution while the second was at a semi-illustrious one. Needless to say, I chose the second one. The first guy was completely understanding, saying he understood that I needed to make the decision I made. And, looking back now, I can say with certainty that it was an absolutely correct decision. The relatively minor “stamp of approval” from having spent a short time at a semi-illustrious institution has helped me much more than any of the other stuff such as multiple single-author PRLs, plenary talks at major international conferences, and strong recommendation letters from leading figures in my acknowledged-as-“important”-but-less-fashionable-than-string-theory field. And in the quite likely event that I eventually have to leave academia it will count for even more.

  • Count Iblis

    Amused is 100% correct. If you also take into account that a postdoc job involves 60 hours work per week while you get paid for only 30 hours per week, you are far better off leaving academia after your Ph.D. and then work on your favorite science topic in your free time.

  • http://lablemminglounge.blogspot.com/ Lab Lemming
  • Sili

    Once again this advice arrives at least five years too late. I really should have looked into what academia entailed before getting in. Considering how I floundered through my masters, I now don’t understand why noöne stopped me earlier.

    At least I enjoyed myself until I didn’t anymore.

  • Pauline

    Great advice, as usual. How about some for the flip side — “choosing the right postdoc” when you’re the (new) faculty member doing the hiring?

  • http://aclinks.wordpress.com/ Academic Career Links

    There is also a nice series of four papers “What They Don’t Teach You in Graduate School”
    at Inside Higher Ed by David E. Drew and Paul Gray, and a book by the same authors.
    All pertinent links can be found here.


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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .


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