Gender Equality

The incontinent pipeline: it’s not just women leaving higher education

Career advancement is often described metaphorically as a pipeline. In many fields — law, film, business, journalism and academia, to name just a few — the pipeline leaks. And most of all, it leaks women. As we move further along the career path, we usually find a increasing percentage of men and a decreasing percentage of women.

The European Union offers an example from academia. In 2010, 59% of undergraduate degrees went to women while 46% of PhD graduates were women. 44% of entry-level positions at universities were held by women while only 37% of the next level were. By the time we get to full professors, only 20% are women.

More trouble in science

In science and engineering fields, the numbers are even worse: women make up 35% of PhD graduates, 32% of entry level positions, 23% of the middle rank and only 11% of full professors. It’s not just a leak; it’s full-blown incontinence.

Freshly published research gives a more nuanced picture. The traditional recitation of percentages at various points along the pipeline provides a snapshot. The new research is more like a time-lapse film.

Researchers identified students who earned a bachelor’s degree in science, technology, engineering and mathematics. Then they studied the percentage of these students who went on to complete a PhD — something they call the “persistence rate.” They compared persistence rates for men and women. If fewer women than men continue from a bachelor’s degree to a PhD, we can say that the pipeline between these two degrees leaks more women than men.

Are the holes in the pipeline being filled?

Historically men have had higher persistence rates than women; more men have continued for a PhD. In more recent years, we see something else. The persistence rates have coverged; men and women continue in equal rates. That’s great news!

Or so it would seem.

Unfortunately, the new study doesn’t actually show a pipeline being tightened up to leak less. Instead, it shows a pipeline that is leaking even more! The convergence in persistence rates for men and women is not a result of an increase in the rate of women taking a PhD; it’s the result of a decline in the rate of men doing so. It’s as though the holes have gotten bigger — they used to be so small that only women slipped through, but now men slide out, too.

Is this something to celebrate? I can’t imagine why. The first author of the paper, David I. Miller of Northwestern University, is quoted  as saying the study “indicates that women are leaning in when getting their STEM Ph.D.s after college.” Really? How is that? How does bringing the persistence rate of men down to the level of women tell us anything at all about changes in the behavior of women? How does the fact that men seem to be kicking back reveal anything about women leaning in?

Do men and women converge in the same place?

In addition to the dubious celebration of the decline of persistence rates of men, the new research article also looks at an incomplete pipeline. In particular, it leaves aside the important issue of which PhD institutions students get into. For young researchers moving towards academic careers, we know that a few high-prestige universities are responsible for training future faculty members at nearly all other research universities. Are women and men getting into those high prestige universities in the same numbers? Or do women go to lower prestige institutions?

We don’t know. The research methodology doesn’t address this. If the sex of a PhD candidate allows us to predict whether that individual is at a high or mid-prestige institution, then progression through the pipeline is different for men and women. And this difference is likely to affect their future careers. Men and women might avoid leakage in the same numbers but still end up in different places.

More potential for progress

This new research does add to our knowledge. It gives a view over time, it shows that there has been little change in the persistence rates of women and a decline in the persistence rates of men. It also demonstrates the value of early interventions: as the number of women earning bachelor’s degrees has increased, so has the number of women earning PhDs. We should, as the authors advocate, start much earlier in recruiting women to science.

Still they leave important questions unanswered. Why are relatively fewer men completing PhDs than a few years ago? Why are women still not completing more? Has the PhD become an unattractive degree? How can we seal the pipeline, instead of just watching it get leakier? These are the big questions and they require our urgent attention.

We are making some progress in understanding the challenges associated with recruiting women to science and this new study shines a light on important issues. But there’s still a lot of pipe welding to do.

Articles cited:

The bachelor’s to Ph.D. STEM pipeline no longer leaks more women than men: a 30-year analysis. David I. Miller and Jonathan Wai. 2015. Frontiers in Psychology.

Systematic inequality an hierarchy in faculty hiring networks. Aaron Clauset, Samuel Arbesman, Daniel B. Larremore. 2015. Science Advances.

This essay also appears at The Guardian, under the title Don’t be fooled by the closing gender gap in science PhDs.

My interest in moving universities towards balance encompasses gender equality, the communication of scientific results, promoting research-based education and leadership development more generally. Read more



  • Tamara says:

    Hello Curt,

    I just wanted to drop you a quick comment to say that while I think your article poses a number of very valid arguments (and importantly, arguments that other coverage of the Miller-Wai study may have missed), I am just reading an article (Banu Subramaniam’s A Retrospective Essay on Feminist Science Studies) that proposes a critical view of the entire ‘pipeline’ metaphor used for the describing and addressing the presence of women (and now men) in science. I was struck by Subramaniam’s alternative and eye-opening interpretations of the ‘leaky pipeline’ and the implication that staying in said pipeline may not actually be a good thing after all – and this interpretation could really have relevance to how we do “pipe wielding”. Here’s a short quote:

    “We could argue that the pipeline metaphor is a rather good one to describe the experiences of many women in the sciences [but] not their thrill of discovery and exploration. We could also describe the pipes as long, dark, dingy, impenetrable tubes and masses of metal crisscrossing the terrain of industrial capital. We could describe the pipe as one that contains, constrains, limits, and cuts off the oxygen of the travelers within. Imagining the regimented travels in pipes that give the travelers no agency in their journey, we might start rooting for the leaks and for those who escape the drudgery of pipe travel.”


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