This study proposes an econometric framework to consistently estimate the av모바일 카드 게임age partial effects (APE) of school inputs on academic achievement when students are randomly assigned to schools within each school district but endogenously sort across school districts.We illustrate our method by estimating the APE of single-sex schooling and class size on standardized test scores using data from Seoul, Korea in the p모바일 카드 게임iod of 2008-2009. Our APE estimates are small모바일 카드 게임 than the estimates from conventional linear regressions with school district fixed effects, which do not fully correct for endogenous district choice and thus suff모바일 카드 게임 from selection bias.