Parents who volunteer, or who lobby for improvements in school quality, are generally seen as providing a school-wide public good. If so, straightforward public-good theory predicts that free-riding will reduce average involvement at larger schools. This study uses longitudinal data to follow...

Critics of school choice argue that cream-skimming will worsen outcomes for those left behind in public schools. Since "high ability" families may have already sorted themselves out of the schools in question, this paper will examine whether existing within-school heterogeneity leaves any scope...