Reexamining a Multisite Early Childhood Education Program: Gradual Scale-Up, Birth Spacing, and Parental Investment

We reexamine a multisite, randomized, high-quality early childhood education program that unintentionally oversampled twins by targeting premature low-birthweight children. We find that birth spacing determines program effectiveness. For singletons, outcome gains up to age eighteen replicate across sites, and are comparable to gains observed for iconic programs like the Perry Preschool Project. For twins, gains become negative by age eighteen. Program impacts on parental investment (parenting) mediate outcome differences; the program increases parenting for singletons and decreases it for twins. A household production model indicates that the possibility of jointly supplying inputs to twins explains the decrease in parenting.