[simonh]

The original article already provided evidence, based on analysis of the performance of similar students who do and do not get into a selective school. As it says...

"Except that attending those high schools simply doesn’t matter in terms of conventional educational outcomes. When you look at the edge cases – when you restrict your analysis to those students who are among the last let into such schools and those who are among the last left out – you find no statistically meaningful differences between them."

So unless you're calling out the original article, how about offering counter-evidence?