Did Participation of Schools In Programa Escuelas de Calidad (PEC) Influence Student Outcomes? Richard J. Murnane, John B. Willett, and Sergio Cardenas Harvard University Graduate School of Education August, 2006 We would like to thank the many people who provided valuable information about the history of PEC and its operations and answered our innumerable questions. They include Manuel Ávila, Teresa Bracho, Ernesto Castellano, Rafael Freyre, Andres Ortiz and numerous state PEC coordinators and federal officials responsible for administering PEC. We also gratefully acknowledge the helpful comments on an earlier draft provided by participants in a Mexico-Harvard workshop that took place at the David Rockefeller Center for Latin American Studies at Harvard University on August 2 and 3, 2006.