I don't see why it makes any less sense than gender equality in general.
I didn't say it does. (LW has no shortage of people objecting to "gender equality in general". I'm offering a bit of metacontrarianism here.)
If you look at the evidence, as opposed to the squid ink being thrown around to make things "controversial", it's about as well supported as most of the others.
So, just to be clear, are you saying it is well supported or it isn't? It seems to me that it is but there may be a pile of evidence I'm not familiar with.
(What I hope you and James_Miller aren't saying: "Lots of people think there should be gender equality, so let's propose measuring something that everyone knows isn't equal just to poke them in the eye".)
As Scott Alexander wrote "Society is fixed, biology is mutable.". If gender income inequality is caused by society but gender prison inequality is caused by biology then we have more hope of fixing prison inequality.
I got lots of helpful comments in my first post, so I'll try a second: I want to develop a list of criteria by which to evaluate a presidency. Coming up with criteria and metrics on the economy is pretty easy, but I'd like to ask for suggestions on proxies for evaluating: