There’s the leak in the pipeline

We’re always talking about this curious phenomenon, that we see lots of women at the undergraduate and graduate level in biology, but large numbers of them leave science rather than rising through the ranks. Why is that? It seems that one answer is that elite male faculty in the life sciences employ fewer women, that is, the more prestigious, well-known labs headed by male faculty with great academic reputations tend not to hire women for the next level of training.

Women make up over one-half of all doctoral recipients in biology- related fields but are vastly underrepresented at the faculty level in the life sciences. To explore the current causes of women’s underrepresentation in biology, we collected publicly accessible data from university directories and faculty websites about the composition of biology laboratories at leading academic institutions in the United States. We found that male faculty members tended to employ fewer female graduate students and postdoctoral researchers (post-docs) than female faculty members did. Furthermore, elite male faculty—those whose research was funded by the Howard Hughes Medical Institute, who had been elected to the National Academy of Sciences, or who had won a major career award—trained significantly fewer women than other male faculty members. In contrast, elite female faculty did not exhibit a gender bias in employment patterns. New assistant professors at the institutions that we surveyed were largely comprised of postdoctoral researchers from these prominent laboratories, and correspondingly, the laboratories that produced assistant professors had an overabundance of male postdocs. Thus, one cause of the leaky pipeline in biomedical research may be the exclusion of women, or their self-selected absence, from certain high-achieving laboratories.

These statistics were obtained by sampling a large number of labs across the US. The leaky pipeline is rather obvious in this table: note that we have parity at the graduate student level, but that it falls off dramatically at the next level up.


This is a problem. One (not the only one!) of the criteria used to select academic hires is the reputation of the lab they came from — some labs are just really good at cranking out the data, publishing publishing publishing, and new graduates coming out of those labs are likely to continue that pattern. Coming out of a well-known lab provides a real leg-up for an academic career. But what this paper found is that women were less likely to find themselves in those labs.

We found that female trainees were much less likely to work for an elite PI, particularly at the post-doctoral level. Combining faculty of both genders, men were about 17% more likely to do their graduate training with a member of the NAS, 25% more likely to do their postdoctoral training with a member of the NAS, and 90% more likely to do their postdoctoral training with a Nobel Laureate. Thus, the gender skew in employment results in fewer women being trained in the laboratories of elite investigators.

Get with the program, Nobelists!

My first thought was that maybe this was a product of an older generation — that more senior faculty are going to be much older and perhaps unfortunately traditionalist, so all we have to do is wait for them to die off and be replaced. No such luck. When the data are carefully dissected, the correlation isn’t with age, but with elite status (as defined by membership in prestigious organizations). Young male investigators are just as unlikely as old male investigators to hire women.

As expected, among male faculty, elite status was negatively correlated with the percentage of female postdocs in a laboratory (P < 0.0001). This relationship remained true even when several other explanatory variables were added, including faculty rank, years since a faculty member had received his or her PhD, and total number of trainees in a laboratory. As a single independent variable, years since PhD was moderately negatively correlated with the percentage of female postdocs in laboratories with male faculty members (P < 0.045), but this effect disappeared when other variables were included in the model. This observation suggests that a faculty member’s age is not a significant determinant of the gender makeup of their laboratory, and both young and old elite professors employ few women. Laboratory size was also negatively correlated with the representation of female postdocs both as a single variable and in multivariable models. Regression against the percentage of female graduate students in each laboratory revealed similar, although less robust, results. In multivariable models, elite status was associated with a significantly lower percentage of female graduate students trained by male faculty. However, years since PhD correlated with an increasing representation of female graduate students, whereas laboratory size was not significantly correlated in either direction. Finally, we constructed equivalent linear models for female PIs, but we failed to find a single variable that was significantly associated with differential representation of female trainees in these laboratories.

The paper is careful to point out that they don’t know the direct causes of the differences, whether it’s exclusion, conscious or otherwise, by faculty men, or reluctance of women to apply to those labs. We should probably try to figure that one out, since that’s how the problem gets fixed…but it’s probably a combination of all of these factors.

Irrespective of the cause of the gender disparities in elite laboratories, its consequences significantly shape the academic ecosystem. Our data show that these laboratories function as gateways to the professoriate: new generations of faculty members are predominantly drawn from postdocs trained by high-achieving PIs. However, these feeder laboratories employ a disproportionate number of men. According to the theory of cumulative disadvantage, persistent inequalities in achievement can result from small differences in treatment over a prolonged goal-oriented process. In controlled studies, women in academia receive less favorable evaluations, receive lower salary offers, and are ignored by faculty more frequently than men. Access to training in certain laboratories may be another level at which women are disadvantaged. The absence or exclusion of female trainees from elite laboratories deprives them of the resources, visibility, networking opportunities, etc. that could facilitate their professional development. These differences may contribute to the leaky pipeline by shunting women toward laboratories that provide fewer opportunities for advancement in academic science.

I’m certainly not at one of those elite laboratories, so I can’t do much at that level — but I am training swarms of undergraduate women and stuffing them in at the base of the pipeline. One thing we can do here is encourage our graduates to be ambitious and push hard to get into the labs they really want…and to prepare them for the institutional biases that will get in the way.


  1. says

    Interesting. I wonder if some of the underlying reasons are the same as what Claire Shipman and Katty Kay discussed in their recent Atlantic Cover Story that highlighted issues in “confidence” that were reinforced socially.

    Still, a big highlight of how deep the problem goes…

  2. ibbica says

    My own inclination would be to suggest:
    – The elite-ness of the lab (supervisor) is correlated with the (perceived or real?) arrogance of the supervisor
    – The (perceived or real?) arrogance of a specifically male supervisor has a disproportionately negative effect on the inclination of women to want to work with them (i.e. compared to men)

    Leaving the operational definitions to the experts, of course ;) “Arrogance” could probably be replaced or complemented with something like “sense of entitlement” or “unexamined privilege”, but it was the first word that came to my mind when thinking about the people I know of who run “elite” labs.

    Personally, I avoided even applying to work in some of the “top-tier” labs specifically because the (male) supervisors of many of those labs in my field seemed* like arrogant asses and I’d worked with and around enough of those, thank you very much :/

    *On mostly second-hand or first-impression information, I’ll note. I’d met a few briefly at conferences, seen most of them talk publically, and spoken to several of their students who themselves were either exhibiting ‘arrogant ass’ attitudes (which in the absence of other information I perhaps unfairly projected onto their supervisor), or complaining about the supervisor’s attitude. That’s why I’d said “perceived or real” up there, there might be an attitude problem or there might be a perception problem, or both.

  3. katiemarshall says

    As a female postdoc I see the leaky pipeline every day and it’s one of the pieces of evidence I use to show that no, it’s not just historical that we see so few female faculty.

    I do find it a bit odd that the lab someone came from is such an important determinant of their later success. Shouldn’t we be judging people on their own merits, not just their academic lineage? Maybe this is more of a thing in the States (I’m Canadian)? Presumably there’s quite a lot of correlation between performing well and coming from a high-flying lab (more resources in the lab, more co-authored pubs?).

  4. Antiochus Epiphanes says

    I do find it a bit odd that the lab someone came from is such an important determinant of their later success.

    Word. It would seem almost that the contrary should be true. To be productive without the help of a strong advisor is much harder than to be productive in a large well-funded lab. I interpret the former as a mark of worth. Maybe there’s all kinds of irrationality at work here*. As a PI, this is clearly to my advantage in that the talent pool has become rather deep.
    *My own experience maybe prejudices me in this regard. My advisor was not so great, and I sometimes have resented the lack of access that came from that. Not much lately, but when I was on the job market. So.

  5. octopod says

    (Psst, PZ — you posted a link that goes through the UMM library proxy.)

    This is the link you want. Don’t worry, it’s open access.

    I think a sufficient explanation for this is as follows:
    — Everyone has some kind of threshold of interestingness/importance below which they don’t bother replying to their mail.
    — “Elite” faculty have a higher impression of their own status, and therefore a higher salience threshold for answering. Therefore, they reply to a smaller proportion of prospective grad students or postdocs who send them letters of interest.
    — A female name lowers your interestingness by a nonzero amount.

    You don’t even need to get out into the weeds with questions of whether women are putting themselves forward less. I’m not convinced they do, at least not at the post-undergrad stage. Possibly at the post-Ph.D. stage.

  6. says

    Interesting… I would love to see the pattern of application and acceptance however. I can’t help wondering if there is a practical aspect to this… It takes a lot of work and hours to progress through the post-doc ranks to get on the professor ladder, and the more elite labs tend to make greater demands on their post-docs. As much as society would like to think of itself as egalitarian, the level of sacrifice required to succeed in academia is more socially acceptable for men than for women, given that even in this decade women still tend to do more of the housework and child rearing tasks. Couple that with the poor pay and insanely skewed work-life balance, and you have a sound economic reason for a member of either sex (but more so the one expected to invest more in the ‘life’ side of that balance) to leave the academic mill.

    From my own experience, I did my PhD in a very good (though not “elite”) lab with a slight female skew in terms of post-docs and grad students. Of the people I knew during my tenure in that lab, only two of the male members continued with a career in science – the rest of the men (including myself) and all of the women eventually left academia for more lucrative careers in the ‘real world’. One data point, I admit, but I can’t help notice that just as society has become accepting of female scientists, science as a career has unfortunately reached a point of oversaturation, poor pay, poor working conditions, and endless short term post-doc contracts that acts to dissuade people of either gender from pursuing science as a career.

  7. A. R says

    One data point, I admit, but I can’t help notice that just as society has become accepting of female scientists, science as a career has unfortunately reached a point of oversaturation, poor pay, poor working conditions, and endless short term post-doc contracts that acts to dissuade people of either gender from pursuing science as a career.

    This is just a big of a problem. The solution, of course, is to give the NIH and NSF massive amounts of money to fund science.

  8. says

    Well, no… the solution to poor quality of academic life is to stop manufacturing so many grad students, given that academic promotion is ‘dead mans shoes’, and make the ones who remain realize that their skill set is both highly transferable and lucrative. As it is, you have hundreds of grad students and post-docs competing for a tiny number of assistant professorships, none of them realizing that businesses will pay them quite a bit of money to become predictive modellers and business analysts. The reality is that senior academics should be competing against such companies as Accenture and KPMG to hire the best and brightest, and thus offering better pay and working conditions. Most grad students never even realize that there is a whole other career path – not as interesting, but much better economically. The academic mill relies on that, so that instead of competing against business, they make grad students and post-docs jump through ever more hoops under the illusion they have no other choice.

    As for more funding for science, sure that would be great, but the number of times I’ve seen professors champion equality and egalitarianism as an abstract, and then use their grant funding to pay their post-docs and grad students starvation wages…

  9. A. R says

    Oikoman: If someone is willing to spend 10 years working toward a degree in a specific field, are you prepared to tell them that they can’t do that because there are too many grad students already? Or do you propose some other means of limiting the number of new grad students, realizing that many institutions will use what ever you come up with to disenfranchise some group or another? And you do realize that most businesses refuse to hire PhDs for most positions because we cost too much, right? Even if they did, there aren’t that many people who would be willing “spend” their PhD on some boring corporate job that someone with an MS or even an MBA [*spits*] could do? If someone spends the time to earn a PhD, they probably like research, and that isn’t something a corporate job could offer.

  10. a_ray_in_dilbert_space says

    Oikoman: “One data point, I admit, but I can’t help notice that just as society has become accepting of female scientists, science as a career has unfortunately reached a point of oversaturation, poor pay, poor working conditions, and endless short term post-doc contracts that acts to dissuade people of either gender from pursuing science as a career.”

    It may not be coincidence. As a physics grad student in the ’80s, I was involved in several efforts to try to increase the opportunities for women in physics. As part of those efforts, I noticed that several countries had substantially higher proportions of women physicists than the US–and these were not countries one would call feminist–Portugal, Italy… It turns out that in those countries physics professor was not a particularly prestigious position, so it was more open to women.

    Now that America has turned full blown anti-science, we may finally see near gender parity.

    FWIW, I too left the academic track, although I do work for a lab run by the ebil gummint.

  11. gillt says

    Oikoman: Your commentary makes more sense to me if you ignore the gender variable and assume that elite status is the only thing being considered in the study. Or maybe you don’t think there are any elite female faculty to begin with?

  12. Antiochus Epiphanes says

    … you have hundreds of grad students and post-docs competing for a tiny number of assistant professorships, none of them realizing that businesses will pay them quite a bit of money to become predictive modellers and business analysts.

    Whatever floats your boat, I guess. I don’t generally think the business model is all that good in promoting discovery, which is why most people get into science in the first place. They want to discover interesting shit. That being said, I think academic advisors are obligated to level with their students about the competition they’ll be facing when they leave. More importantly they should also be making fair decisions when hiring post-docs and tenure-track colleagues.
    Maybe hearkening back to the point of the OP, I wonder if businesses are any more adept at promoting careers of women grads than academia is. I don’t guess they are, but I don’t now. Maybe you have some insight into that Oikman?

  13. says

    Seriously? Basic economics of supply and demand are telling these grad students and post-docs that they can’t do what they want to… do you really think that all of these grad students get faculty jobs? As for businesses refusing to hire PhDs, no they don’t cost too much (if anything, they tend to undervalue their own skills at first) though after a few years of business experience their earning potential shoots up fast. There are a lot of PhD’s in ‘boring corporate jobs’, incidentally… I work in finance with math, stats, engineering and medicine PhDs (my own is in molecular biology). Sure, the work isn’t rocket science, but having a research degree means you can get the more interesting work out there.

    Science is a career path similar to acting, writing and professional athletics – a small number of highly paid, well recognized elites and a large number of wannabes struggling to make it. In these fields you can be really really really good… better than 99.999% of the world population.. but if you aren’t quite good enough, your still going to fail. Unlike a lot of these all or nothing career paths, if you can’t quite make that assistant professorship, or tenure eludes you, you still have a lot of options. Most just don’t realize it.

  14. says

    Gillt: This is where I would love to see the application data… without knowing whether women are applying to elite labs and not being hired, or just not applying, its hard to say. I wouldn’t ignore the economic aspect however….

  15. gillt says

    Application data? That’s not how post-doc hires work. It’s an informal process involving emailed CVs and a face-to-face.

    To reiterate: not just about elite labs but elite labs where guys are in charge.

    We note, however, that female investigators at the top of their respective fields run laboratories with just as many women as other female PIs….Thus, in addition to the aforementioned factors, we suggest that gender bias may contribute to the decreased employment of women in laboratories with elite male PIs.

  16. Antiochus Epiphanes says

    On equity in industry: a quick google
    Of note:

    Glass ceilings for women in industry: Women are under-represented in science and engineering management positions, compared with their overall representation in these industries:  In 2008, women scientists and engineers employed in business or industry held 20% of all management and 15% of non-S&E top-level management positions, compared with their 21% representation in S&E business and industry overall.  Women held only 6% of engineering management and 20% of computer and information systems management positions.*

    *National Science Foundation. 2008. Women, Minorities and Persons with Disabilities in Science and Engineering. Division of Science Resources Statistics.

  17. Suido says

    A.R. #9

    This is just a big of a problem. The solution, of course, is to give the NIH and NSF massive amounts of money to fund science.

    Oikoman #15:

    Seriously? Basic economics of supply and demand are telling these grad students and post-docs that they can’t do what they want to… do you really think that all of these grad students get faculty jobs?

    @Oikoman: A.R. proposed an increase in the demand, via massive increases in science funding. Hence, more faculty jobs for all. Yet you continue to write paragraphs about how few jobs there are, like that’s a paradigm that can’t be changed. Why?

  18. A. R says

    Oikoman #15:

    As Suido said, I am proposing that demand meet supply, as opposed to your suggestion that supply meet demand. The former rarely turns out well when the supply is of highly educated people, particularly when it is so simple to increase the demand. You are thinking within the wrong paradigm here. Instead of telling thousands of graduate students and post-docs to abandon their PhDs or waste them on corporate drivel, we could tell the incompetent cretins who supposedly represent us to fund science at a reasonable level. And along the way, perhaps we can make a few modifications to the academic edifice to facilitate a more efficient and equitable system.

    (For reference, my PhD is in Experimental Pathology, and my specialty and skillset fall within a very specific field with relatively low levels of competition.)

  19. Sids says

    I may have misunderstood the study, but one thought that struck me is that there may be parity amongst graduates now, but that wasn’t always the case. As such, while the male/female split may be 50:50 amongst 20 somethings, men would still predominate amongst the 30’s, 40’s and 50’s, ie the ones with more experience that will be prioritised in hiring. This would be slow to fix, as women need to be in the industry to get the experience. This would make sense with the Nobel laureates since they can be selective and take the most qualified candidates. Otherwise, I’m not sure why they would be so much worse than the rest of the population on this.

  20. Suido says

    @ Sids #23

    That’s an argument that is well out of date. Women first reached parity with men in terms of enrolment in biological sciences in the US in the mid-late 80s. That’s nearly 30 years ago. Those graduates are now pushing 50 years old, and so we should only see men predominate in the 50+ age category.

    Otherwise, I’m not sure why they would be so much worse than the rest of the population on this.

    I wouldn’t say they’re worse, just depressingly similar in terms of institutional and unconscious sexism.

  21. says

    Gillt #19: Every post-doc I’ve had (or turned down) has involved a formal application and hiring process, even in the cases where I had been able to prepare the ground ahead of time. HR policies may be different where you live however.

    Suido #21: Its a classic overpopulation scenario: the number of graduate students produced far exceeds the number of faculty positions available, and even doubling the number of universities would only temporarily solve the problem, as each new faculty member starts churning out their own graduate students. Fortunately in the STEM fields, business and industry can absorb a lot of the excess, but very few graduate students are taught any business and consultancy skills which makes the transition across more difficult than it has to be.

    The biggest difference between academia and business is that a senior technical level position in business (e.g., a senior credit risk analyst) can command a high salary, a secure position, and a high level of professional respect, without the need to move into a management role. In academia, the equivelant role (post-doc) is generally poorly paid, short term contract work. I’ve known PhD’s who have moved into support roles (senior technician), where they get better pay, working conditions and permanent positions, but they then lose the respect of their academic peers.

    Simply throwing more money at the problem, as A.R. suggests, won’t change anything until the work culture changes, and my suspicion is that it is this work culture of poor pay and worse work-life balance that may be either affecting the decision of women to apply to the most elite (and thus most intense) labs, or which may be influencing the judgement of the PI’s of those labs in their hiring decisions (there is still an attitude, both in business and academia, that women would not be as dedicated to their work, preferring to spend more time with their family).

  22. chigau (違う) says

    Since almost all of the problems have been caused by removing money
    ‘throwing money at the problem’
    is the first step in alleviating the problem.

  23. Sids says

    @Suido Fair enough, I stand corrected there. I would still say that if there were issues in the time since parity that kept women from working the field, then the problem would still be echoing well after it was fixed, so in that case it would take time to see the results. I don’t that would at all cover the duscepancy here though. There’s still more to be done.

  24. says

    As a biology grad in the mid-90s, a cis white male outnumbered by females, who at the time was SO CONFIDENT that sexism was dying because more women than men were entering biology and they were all awesome and I wasn’t sexist at all and… well, privilege (sorry about that), this makes perfect sense. Sexism is way more rife than I’d have admitted at the time. Hell, one of the profs was “legendary” for his trysts with grad students.

    Sigh. Also barf. Mainly sigh.

    It’s awesome that of my friends back then, the only ones who are still in academia are indeed the ladies. They toughed out much more than I even conceived of, and stuck with the science. I suspect again, I was lucky to be amongst a group of friends that was so egalitarian (from my POV). And again I’m trying to work out how much I missed and how badly those female friends were treated by the system, in ways I missed totally.

    When the blinkers are ripped off, the light hurts.

    Trying to do better.

  25. Antiochus Epiphanes says

    I think there is a lot that is wrong here.
    1. I would be thrilled if basic science were more strongly supported, but I don’t see how that will alter the pattern of systematic discrimination against women in academia.
    2. Women who leave academia for industry jobs still face systematic discrimination. However wonderful a career in industry might be, it isn’t so wonderful for women as it is for men.
    The solution seems obvious, but its difficult because it requires distributed action by those who are causing it. PIs of “elite”* labs and industry managers must remove their heads from between their ass-cheeks and begin to see the world differently. This won’t happen in a distributed way until funding agencies, university administrations, and boards of directors (or whatever you call the people who set hiring policy in industry) require it.
    I’m no economist or like, business buff, but it seems obvious to me that there should be some economic motivation. How is ignoring 50% of the talent pool a good employment policy?
    *I don’t know that “elite” is really the best word here, but whatevs.

  26. says

    Antiochus #29: I won’t argue that industry has solved all the problems – they haven’t, but below the boardroom level, they do a hell of a lot better than academia in gender balance (in this country at least – in the US your milage may vary). I’ve noticed that the more family friendly a company is in its work-life balance, the more women occupy senior roles – in contrast, academia has never been family friendly. Again, that can work both to reduce applications for senior research positions, and to create a culture a the senior level that prefers a male candidate to a female candidate on the (prejudicial) basis that the latter will be less work oriented. I can’t help seeing similarities between the one area of finance that stubbornly resists gender balancing – investment banking – where the hours and pressures are similar to what would be experienced in an elite lab. In this case at least, the culture among investment bankers is the problem… where I’m curious is whether a similar ‘macho’ culture exists among elite labs. From personal experience, I knew of labs where working 70 hour weeks was a point of pride – but those were also labs where the researchers were barely aware of their own children.

  27. Antiochus Epiphanes says


    Myers, you’re a complete prick. The reason there’s there are fewer women the higher up you go in the ranks is that there’s there’s there are simply fewer women of high higher ability than men.

    Not normally all that into grammar, but your hypocrisy is showing.

  28. Esteleth, [an error occurred while processing this directive] says

    While there was an application form when I got my post-doc, it was pro forma after I’d gotten the position after a volley of emails and face-to-face chats with my future boss.

    I applied to five positions. Every single one of them followed the “trade emails until the PI agrees to hire you, then fill out paperwork at HR” pattern.