Keeping down cost per child? What are you talking about? The cost per child has skyrocketed in the US over last 20 years, particularly among the worst-performing schools. Baltimore spends more per child than Mountain View. NYC spends more per child than Palo Alto.

There is a certain view, popular among many people, that poor performing schools perform badly because they are underfunded. It has been vigorously spread by politicians, teachers, and activists. Well, we ran the experiment. With enormous federal and state spending, we managed to mostly equalize the spending, and, in many cases, fund the badly performing schools more than the good ones. The results of the experiment are very clear: additional funding, by and large, does not *cause* significantly improved educational outcomes. Any observed correlation between school funding and outcomes is a result of who lives in the area, and who attends the school. The casual arrow does not go from funding to outcomes, but from the school population to both funding, and, in parallel, to outcomes.