“Silicon Valley is sexist” is a depressingly common and uncontroversial statement. “Silicon Valley is innumerate,” on the other hand, seems to be pretty false. Except, it turns out, when innumeracy conveniently supports entrenched sexism.

In the latest dust-up at Facebook, an engineer used five years of internal code-review data to try to work out why there were so few women in the senior engineering ranks of the company. What she found was shocking, if not surprising: female engineers received 35% more rejections of their code than men, and also waited 3.9% longer to have their code accepted.

It’s easy to see what’s probably going on here: Facebook’s mostly-male engineers have all manner of biases which result in them treating the female coders’ work more critically. In turn, that results in those female coders remaining lower down in the org chart.


Facebook’s response was horribly tone-deaf: it told employees that it’s bad to share such information with the world, because doing so would damage the company’s “recruitment brand”. Which is to say: If women won’t want to work at Facebook upon learning the truth about the company, the solution to the problem is to make sure they never learn the truth about the company. Hm.

More troublingly, however, Facebook also pushed back on the substance of the report, and did so in a statistically bonkers manner:

Jay Parikh, Facebook’s vice-president of engineering, told engineers internally that the company had conducted its own analysis of the code review process “using confidential employee data so we could gain a better understanding of what is happening”.

The Facebook analysis took into account engineers’ “level” within the company and found “no statistically significant difference” between female and male engineers within the same level.

Parikh attributed the difference that the original analysis found to “the difference in gender distribution between levels”, meaning the fact that Facebook has more female engineers at lower levels than higher levels.

There’s a particularly dismal genre of arguments which basically say that “after accounting for the sexism in our company, we have found that there’s no sexism in our company”. And this one is a doozy.


To spell it out: The more your code is rejected, at Facebook, the less likely you are to rise up the ranks. So the fact that women suffer from significantly higher levels of code rejection is a big problem. The evidence for this being a problem is precisely the fact that Facebook’s female engineers are disproportionately found at lower levels rather than higher levels. 

And yet somehow, Facebook has contrived to use that fact in support of its claim that there isn’t a difference in how male and female engineers at the company are treated. Instead of treating the prevalence of men in the upper engineering ranks as prima facie evidence that there’s something amiss, they use it to exonerate themselves of sexism.

Ultimately, there are two reasons why a woman might see a lot of her code rejected: Either it’s because she’s a woman, or it’s because she’s not very good at coding. For any individual woman, it’s hard to tease those two things apart. But it’s not credible that women as a group are worse at coding than men are. So if the entire group has its code rejected at an uncommonly high level, and ends up in lower-status positions as a result, then that’s clearly sexism at work. Facebook’s suggestions to the contrary aren’t merely offensive. They’re also, statistically, downright innumerate.