Both science and public policy are best advanced based on impartial analysis of all the available evidence. No single study stands on its own, much less provides the definitive answers to policy questions on its own. This requires that scientists and policymakers consider all the evidence rather than simply select a few studies that fit their preconceived notions. The Obama administration's new universal pre-K proposal first announced in the State of the Union address comports conclusions drawn from a full review of the evidence, just as one would hope. Critics of the pre-K proposal in the ensuing debate have not followed the same approach. Their attacks on the President's proposal have been based on a few selected studies considered in isolation and when convenient, misinterpreted. This report from the National Institute for Early Education Research was prepared to set the record straight so that debate can proceed with accurate information. Specifically, the report reviews the research related to four key issues regarding the pre-K proposal. These four issues are in brief: (1) Does high-quality pre-K have lasting benefits?; (2) What is the evidence for the $7 to $1 return on investment in pre-K?; (3) Do non-disadvantaged children benefit from pre-K, and is a targeted or a universal approach to pre-K more effective?; and (4) Are large-scale public programs, including Head Start, effective?