To the extent education policy commentary actually affects policy, it has the potential to do great good or great harm. Several recent commentaries in this field fall into the latter camp, and it’s important to understand why — so that we can avoid similar mistakes in future.


The one I’ll discuss here is this blog post by Matthew Yglesias, in which he draws broad conclusions about the functioning of education markets from a recent study of a tiny school choice program in Milwaukee as well as from some older unspecified research [for the latter, Yglesias linked here, but the body of that page doesn’t discuss school choice]. The Milwaukee study is part of a vast literature. Over the past quarter century at least sixty-five studies have compared outcomes in public and private schools around the world, reporting 156 separate statistical findings.


The evidence of this literature is starkly one-sided. The vast preponderance of findings show private schools outperforming public schools after all the normal controls. What’s more, when we focus on the research comparing truly market-like systems to state-run school monopolies, the market advantage is found to be even more dramatic (see Figure 2 in the paper linked above). To draw policy opinions from a small, selective handful of those studies while ignoring the rest is policy malpractice, and it is dangerous to children.


Even the recent Milwaukee result described by Yglesias as a failure shows voucher students in private schools performing as well as public school students who receive roughly 50% more government funding. How is a program that produces similar academic results to the status quo at a much lower cost to taxpayers a failure? And what of the research suggesting that students in the Milwaukee voucher program graduate at higher rates than those in public schools?


More importantly from a long term policy perspective, how is a program limited to 20,000 or so children in a single city, being served almost entirely by non-profit entities, a test of market education? Would Apple have spent hundreds of millions developing the iPhone or the iPad if its market were limited to the same customer base? Of course not. The dynamism, diversity and innovation we have come to expect from competitive markets in other fields relies on the prospect of ultimately scaling up to serve mass audiences. Without the prospect of a large-scale return on investment, there is no incentive to invest in the first place.