School vouchers, a school choice policy that allows students and families to use public funds to fully or partially pay the cost of attending private schools, became a major area of policy debate once again during Betsy DeVos's tenure as United States Secretary of Education. Recent evaluations have found negative impacts of vouchers on academic outcomes among students using them, particularly on academic test scores, although older research has found mixed results. However, the input side has received less research attention; we know relatively little about the costs of implementing voucher systems. This policy brief provides an overview of the literature on the effects and costs of vouchers and applies recent empirical evidence on policy effects, behavioral responses, and contextual factors to determine administrative costs of a universal voucher system. It concludes with recommendations for further research and policy.