I think this can be misleading in the same way some charter school results are. The easiest way to improve a school's results isn't to improve the education provided, it's to get rid of the worst performing kids. Charter schools do this by various selection effects, and artificial barriers, like ending at noon on a Wednesday. So the only kids who go there have two parents, one who probably is stay at home and can pic…
Education is mostly about your peers. It's obviously true for prestigious universities but it's just as true for elementary schools. Charter schools kicking out problematic students isn't some loophole, it's the main point, and it absolutely can improve the education for those that remain. My district has a quarter of high schoolers in charter schools. Almost all of them under the poverty line. It's not like they're…
But it is sort of what schools currently do. The filter public schools use is housing. You have to buy a home in the school district. That is the reason real estate values are driven by school test scores. Because the opposite is also true: school test scores are a function of who own homes near the school. At the end of the day, maybe that operates better at sorting good apples from bad. I’m probably more in agreement with your line of thinking that making choice easier for poor folks could be best for society, but the selection effect is weaker if you loosen the filter.