Using Boundary Changes to Estimate the Impact of School Competition on Test Scores

We study the impact of school choice on test score outcome. It has generally proved difficult to isolate exogenous differences in the degree of competition faced by schools. We run a difference-in-difference analysis, exploiting a local government reorganisation to provide identification. This reorganisation changed the boundaries of education markets. We analyse one cohort of children passing through secondary school before the change, and one afterwards, both for the treated (re-organised) area and for similar control areas. Our point estimates suggest that the fall in competition experienced reduced test scores, but the estimates are not statistically significant.