This policy brief closely examines and summarizes the evidence regarding school choice and its impact on student achievement. After surveying studies across various choice forms, the authors selected 87 based on specific criteria. Each of these has been analyzed and assigned impact and quality ratings. Impact ratings indicate whether the choice schools' student performance was better or worse than comparison groups'; quality ratings reflect a study's score on a weighted scale that assesses six dimensions of research design. Results for both impact and quality ratings are summarized and mapped to facilitate reference and comparisons. Overall, the existing body of research on school choice reveals a mixed picture, with some studies suggesting positive impacts, and others indicating negative impacts. Large differences appear across school choice types in terms of the amount of research available, the overall quality of the research, and the conclusions the research supports.