Here are two things that everyone interested in education should know: some of the top performing schools in the country are charter schools, and, on average, charters do not perform significantly better than traditional public schools. The former point is exemplified by the likes of the American Indian Public Charter Schools in Oakland (which the local board recently voted to shut down), and the second by the latest national report from Stanford University’s Center for Research on Education Outcomes.
There is no necessary contradiction between these two findings. It could simply be that there is higher variance in charter schools than in regular public schools, which would cause charters to be over-represented among top and bottom performers without necessarily differing from regular public schools on average.
Charter optimists believe that to be the case, and they expect that consumer choice and the ability of low-performing charters to fail and close down will gradually raise average performance as good charter networks crowd out bad ones. There is even some evidence that things may be moving in that direction—results of the latest Stanford U. study are less bleak than those of the previous one.
The most dedicated charter school optimists are perhaps the philanthropists who are subsidizing their growth. But this is where the problems become most visible. A couple of years ago, I studied the many dozens of California charter school networks to measure the correlation between their academic performance and the amount of philanthropic funding they had attracted. In a nutshell, there isn’t one. There is, in fact, a stronger correlation between the length of a charter network’s name and its academic performance than there is between its grant receipts and its performance.
Philanthropists are indeed helping to scale-up charter school networks, but they are doing so effectively at random—much like the lotteries by which over-subscribed charters must admit their students.
This should not be too surprising. Many philanthropists talk about getting a return on their investments, but, in practice, they lack the incentives to do so that characterize for-profit investors. Philanthropists are in the business of giving money away. Investors are in the business of bringing it in. The former do not expect a financial return on their investments; the latter do.

