Abstract

We summarize the available evidence on the extent to which expenditures on early childhood education programs constitute worthy social investments in the human capital of children. We provide an overview of existing early childhood education programs, and then summarize results from a substantial body of methodologically sound evaluations of the impacts of early childhood education. The evidence supports few unqualified conclusions. Many early childhood education programs appear to boost cognitive ability and early school achievement in the short run. However, most of them show smaller impacts than those generated by the best-known programs, and their cognitive impacts largely disappear within a few years. Despite this fade-out, long-run follow-ups from a handful of well-known programs show lasting positive effects on such outcomes as greater educational attainment, higher earnings, and lower rates of crime. It is uncertain what skills, behaviors, or developmental processes are particularly important in producing these longer-run impacts. Our review also describes different models of human development used by social scientists, examines heterogeneous results across groups, and tries to identify the ingredients of early childhood education programs that are most likely to improve the performance of these programs.