The formula can just as easily be applied to other fields; all that’s needed is reliable data on the field’s gender distribution, which can usually be gathered by way of industry associations and/or government statistics.

I spoke with Martin about his analysis, its implications, and whether it might finally convince conference organizers to stop making excuses.

Lauren Bacon: What prompted you to calculate the statistical probability of all-male speakers’ lists?

Greg Martin: While I’d love to claim it was my idea originally, that’s not the case—I came across a Conference Diversity Distribution Calculator by Aanand Prasad on the web. Prasad further credits inspiration for the idea to comments by Dave Wilkinson and Paul Battley.

As a side note, following Prasad’s links to those comments leads to two web pages—this one and this one—concerning tech conferences within the last three years that were criticized for inviting men almost exclusively; reading the rest of those comment threads reveals how truly dismissive and defensive people get when gender disparity is pointed out. Sadly, we still have a long way to go.

Bacon: If I understand your conclusion correctly, the odds of having zero women speakers at a math conference are next to none.

Martin: If conference speakers were being chosen by a system that treated gender fairly (which is to say, gender was never a factor at all), then in any conference with over 10 speakers, say, it would be extremely rare to have no female speakers at all—less than 5 percent chance, depending on one’s assumption about the percentage of women in mathematics as a whole.

Turning that statement around, we conclude that any such conference without any female speakers must have come into being in a system that does not treat gender fairly.

Bacon: So then why do so many STEM events still have so few women at the front of the room?

Martin: There are many possible reasons why a STEM event might have vanishingly few women among its speakers. Outright sexism and misogyny are rare these days (I hope!), but it still happens. Much more common, I believe, is that all of us carry implicit biases—internal prejudices, difficult to detect in any individual instance, against the idea that women can excel in science and math. These biases have been shown to literally alter our perception of women in STEM fields, so that we evaluate them as being less accomplished as men with identical CVs. This (unintentionally) unfair evaluation of women by conference organizers, together with the psychological tendency to first call to mind stereotypical representatives of categories (for example, male mathematicians), lead them to come up with speaker lists consisting disproportionately of male speakers.

Unless we consciously try to observe the gender composition at conferences, the same biases cause us not to even notice that there are far too few women to be the result of a fair process; and so the injustice is perpetuated.