This study was made possible by the collaboration and hard work of many individuals beside the study authors. We are grateful to the leaders in two school districts, principals, teachers, and thousands of first-and second-grade children and their parents or guardians who agreed to participate in the study and responded to the many waves of data requests that form the basis of this report. Many unnamed school secretaries, registrars, district-level data managers, and institutional review boards at the two school districts played important roles in providing access to critical data. We are particularly appreciative of the willingness of Linda Levi and the other members of Teachers Development Group to take part in this evaluation.