S tandardized testing plays an important role in reform, but it is not a silver bullet. A statewide testing program informs parents and legislators and exposes schools that are performing poorly. Unfortunately, most of the gain comes when the information is used not merely to inform debate but to give schools incentives to improve.
Parents can create such incentives by exercising school choices informed by test results.
Alternatively, a state can create a system of penalties or rewards for schools. School choice, however, is rare, and reward systems are hard to construct. I was wrong. Not only had I underestimated how much schools would improve to avoid being exposed, but I had not realized how inexpensive testing is. Testing is undoubtedly the school reform with the highest ratio of benefits to costs.