As President Obama continues to roll out his proposal for universal preschool as outlined in his State of the Union address, it is worth looking at results of these types of programs in states that already run such programs.
In a paper with Wiliam Gormley (Journal of Human Resources, 2005 (pdf)) and another with Gormley, Phillips, and Dawson (Developmental Psychology, 2005(pdf)), we studied the impact of Oklahoma's universal pre-K program on children's readiness for kindergarten. In the JHR study, which relied on the results of a school-readiness assessment developed by Tulsa Public Schools, We found that attending pre-school boosted school readiness for Hispanic and black students but not for whites. We also found that pre-school had a bigger effect on school readiness among students who qualified for free lunch at school, than those who did not. In the other study, which relied on a standardized and widely-used assessment of school readiness, we found that attending pre-school improved school readiness for students across all racial and income groups.