Dosage Effects of Classroom-Based Interventions on Children's School Readiness: Evidence from a Randomized Experiment in Head Start Settings

Fuhua Zhai, New York University
Cybele Raver, New York University
Stephanie Jones, Harvard University
Christine Li-Grining, Loyola University Chicago
Emily Pressler, New York University
Qin Gao, Fordham University
Darlene Jones-Lewis, City of Chicago, Office of Children and Family Services

The variations in program compliance, or dosage levels, of social interventions and their effects on program outcomes have received increasing attention, yet remain poorly understood. This study examined the dosage effects of the Chicago School Readiness Project, a randomized, multifaceted classroom-based intervention in Head Start settings. Using a principal score matching method to address the issue of selection bias, this study found that compared to intention-to-treat estimates, high-dosage levels of teacher training and mental health consultant (MHC) class visits had larger effects on children’s school readiness while low-dosage levels of treatment had smaller or statistically nonsignificant program effects. Moreover, individual MHC services for high-risk children also had significant effects on their school readiness. Implications of these findings for research and policy are discussed.