Factorial designs are widely used for studying multiple treatments in one experiment. While "long" model t-tests provide valid inferences, "short" model t-tests (ignoring interactions) yield higher power if interactions are zero, but incorrect inferences otherwise. Of 27 factorial experiments...

Performance pay for teachers is frequently suggested as a way of improving education outcomes in schools, but the theoretical predictions regarding its effectiveness are ambiguous and the empirical evidence to date is limited and mixed. We present results from a randomized evaluation of a...

We present experimental evidence on the impact of a technology-aided after-school instruction program on learning outcomes in middle school grades in urban India, using a lottery that provided students with a voucher to cover program costs. A key feature of the program was its ability to...