Inputs in the Production of Early Childhood Human Capital: Evidence from Head Start

School Reform, October 2015

A study con­ducted by Christopher Walters finds that Head Start cen­ters offer­ing full-day ser­vice boost cog­ni­tive skills more than other cen­ters, while Head Start cen­ters offer­ing fre­quent home vis­it­ing are espe­cially effec­tive at rais­ing non-cognitive skills. Other key inputs, includ­ing the High/Scope cur­ricu­lum, teacher edu­ca­tion and cer­ti­fi­ca­tion, and class size, are not asso­ci­ated with increased effec­tive­ness in Head Start. Together, observed inputs explain a small share of the vari­a­tion in Head Start effectiveness.

Studies of small-scale “model” early-childhood pro­grams show that high-quality preschool can have trans­for­ma­tive effects on human cap­i­tal and eco­nomic out­comes. Evidence on the Head Start pro­gram is more mixed. Inputs and prac­tices vary widely across Head Start cen­ters, how­ever, and lit­tle is known about vari­a­tion in effec­tive­ness within Head Start. This paper uses data from a multi-site ran­dom­ized eval­u­a­tion to quan­tify and explain vari­a­tion in effec­tive­ness across Head Start child­care cen­ters. Walters answer two ques­tions: (1) How much do short-run effects vary across Head Start cen­ters? and (2) To what extent do inputs and prac­tices explain this vari­a­tion? To answer the first ques­tion, the author devel­ops a ran­dom coef­fi­cients sam­ple selec­tion model that quan­ti­fies het­ero­gene­ity in Head Start effects, account­ing for non-compliance with exper­i­men­tal assign­ments. Empirical Bayes esti­mates of the model show that the cross-center stan­dard devi­a­tion of cog­ni­tive effects is 0.18 test score stan­dard devi­a­tions, which is larger than typ­i­cal esti­mates of vari­a­tion in teacher or school effec­tive­ness. Next, the author assess the role of inputs in gen­er­at­ing this vari­a­tion, focus­ing on inputs com­monly cited as cen­tral to the suc­cess of model programs.