Over the years, advocates for education reform have championed a range of strategies including accountability through high-stakes testing, incentives for students, teachers, small class sizes, parental involvement, school uniforms, technology in classrooms, extending the school year, curricular change, and so on. One recurring and consistent argument for school improvement and student achievement has been that students of lesser means do better in mixed settings or when grouped with students of higher means. This idea, that the rising tide lifts all boats, has been at the core, or at least figured as a central argument, in several social movements in education reform: racial integration during the civil rights movement, mainstreaming efforts for children with disabilities, efforts to counteract social economic segregation, and in blended-ability learning and anti-tracking classrooms. This Article will explore the osmosis theory of student performance by examining vouchers in private schools. It will consider this question by examining two different accounts of the impact of private school immersion on underprivileged children. I will take into account the historical and often anecdotal accounts of underprivileged, often minority, students who achieve significant successes after desegregating elite private schools, and contrast those accounts with underprivileged students who have fewer successes after transferring to private schools using vouchers. I proceed in four Parts. In Part I, I consider the allure of private school education and explain why ultimately private schools cannot provide a solution to ailing public school systems. In Part II, I acknowledge the popularity of vouchers and consider the studies that show their questionable merit. I conclude that given the political need to take vouchers seriously despite the weak evidence to date on their success, it is imperative to begin a dialogue about “what works” for underprivileged students in the private school context. Part III considers the differences among private schools and begins to provide cautious advice to parents armed with vouchers who seek a better solution for their children. In Part IV, I conclude that when no suitable options exist that will make a real difference for their children, parents would be better served in rejecting a voucher. This Article is a modest attempt to begin the conversation that will assist underprivileged families in being better consumers in this new educational marketplace