Saturday, March 11, 2017

AAS: There Is No "Leaky Pipeline" in Astronomy

Yesterday, noticed a piece by Kevin Marvel, published in the American Astronomical Society's publication Status back in January 2016. Here he notes the demographic changes in the discipline:

[W]e can clearly see an ongoing trend ... : the fraction of AAS members who are women is going up and that trend has continued monotonically since the first reliable data I have available in electronic form. Also, once AAS members reach the postdoctoral stage, roughly the age bracket 28–32, the fraction of women moves forward nearly uniformly over time to the next higher age bracket — except in the oldest age bracket, where women’s longevity becomes quite obvious. We are not, actually, recruiting new female AAS members once they hit 83 years of age!

Let me pause there to point out something that perhaps deserves more attention. Men have well known early-career advantages over women related to the two-body problem and motherhood. Among astronomers who got their PhDs in, say, 1997, current career status is likely to systematically vary by gender, simply because women in their thirties have other priorities than men or, perhaps, because they are under other societal and familial "pressures" (which you are free to take as a euphemism for "sexism", though I think the direct systemic effect of that particular pressure is very small). Men, on average, probably get further along in their career in the first twenty years than women do.

But Marvel here points to the possible justice of this arrangement: men die younger too. They have shorter careers. Perhaps this can also be connected to the idea that women are held back by being more ethical. In the long run, and since women can play a longer game, this turns out to be an advantage. But that's all pretty speculative, of course.

Anyway, here's the part that caught my eye:

This positive demographic change repeats all the way back to the first data set and tells me that once a woman has her Ph. D. and is an AAS member, she tends to stay an AAS member and, I assume, an active astronomer. This is a good sign, as it shows that there is no leaky pipeline, at least for AAS membership. It may tell us that women who choose to join the AAS see benefit in membership throughout their career and stay members — quite heartening from where I sit. But what it certainly shows us is that there is an ongoing demographic change in our membership, one that stands in stark contrast to other closely aligned disciplines.

Astronomy, Marvel here tells us, appears to be one of the most welcoming disciplines for women when compared to "other closely aligned disciplines". (It's one the places they feel most welcome to stay, we might say.) It's ironic that Marvel should have found "heartening" news like this, just a few months after Geoff Marcy had been forced into retirement on the grounds that he represented merely the "the tip of the iceberg" of an allegedly systemic harassment culture in his discipline. As I've noted before, there is little credible direct evidence for a culture of harassment in astronomy and a great deal of indirect (proxy) evidence for its non-existence. The absence of a leaky pipeline is one such proxy.


Anonymous said...

"There is no leaky pipeline, at least for AAS membership" is a Marvelous interpretation. The graphs he presents, by Nancy Morrison, are (Figure 1) a bar plot of women stacked atop men (darker-colored bars over lighter-colored bars), and (Figure 2) a histogram of 2015 membership data by age. There IS a leaky pipeline for AAS membership, and it occurs for both genders, as evidenced by the flat-topped distribution of Figure 2, namely that there are ~500 members in each of the ~10 bins between ages 23 and 72. The Marvelous graphs could be interpreted as "In terms of net AAS memberships, women leak less than men, as they age."

AAS membership

Year Total Annual_Growth
2012 7220 0.028
1998 6700 0.133
1989 5000 0.155
1979 3500

The growth of membership has slowed considerably in the 21st century, compared to the 20th. That is the more important story, not shown in the Marvelous graphs.

Here is the AAS membership from 1960 to 1990

and the breakdown by age for 1987 and 1973 compared to physicists for 1986.

(I could not easily find more recent plots.)

Anecdotally, I would say that astronomers value AAS membership more in the early stages of their careers than later. At some point, some stop paying dues.

On the other hand, the growth in AAS meeting attendance, I would guess, has shown more consistent growth over the decades than the total membership would suggest. I leave that to some other person to tabulate.

Anonymous said...

In the comment above, the growth rates were computed incorrectly.
A corrected table is below.
The conclusion remains the same: growth has slowed considerably.

AAS membership

Total Annual Growth
2012 7220 0.0054
1998 6700 0.0331
1989 5000 0.0363
1979 3500