[PunchTornado]

Aren't all gender pay studies like this? When they say women earn 80% less than men they don't take into account qualifications or jobs.

[arkh]

They don't. They usually take the average of all working men and average of all working women. Some go with not just working but "of working age".

[laylao]

Do they usually use average instead of median? That terribly skews the numbers with the top 0.2% being weighted much more highly than the bottom 99.8%.

The gender distribution for the top 0.2% doesn't matter since most men and women will never reach that income.

[Reedx]

Right, they generally fail to take numerous factors into account. Once you start controlling for things (like choice) the gap quickly shrinks.