From the abstract: "...We demonstrate how developmental researchers can exploit the random-assignment designs of multisite studies to investigate characteristics of programs, such as preschool center care quality, that cannot be randomly assigned and their impacts on children’s development. We found that the quality of preschool care received by children has significant, albeit modest, effects on children’s academic school readiness, with effect sizes of .03 to .14 standard deviation increases in academic achievement associated with a 1 standard deviation increase in quality..."