A possible trade-off between greater efficiency and equal opportunity is central to the debate on school vouchers, for instance. Whereas economists since Milton Friedman have argued that school choice would align provider incentives with the interests of consumers and thus lead to increases in...

Several countries have implemented programs that use test scores to rank schools, and to reward or penalize them based on their students' average performance. Recently, Kane and Staiger (2002) have warned that imprecision in the measurement of school-level test scores could impede these efforts....

Although class size has attracted great interest as a policy instrument, inferences on its effects are controversial. Recent work highlights a particular way to consider the endogeneity issues that affect this variable: class size is often correlated with enrollment, which may in turn be related...