Cluster randomized trials involving participants nested within intact treatment and control groups are commonly performed in various educational, psychological, and biomedical studies. However, recruiting and retaining intact groups present various practical, financial, and logistical challenges to evaluators and often, cluster randomized trials…

This paper presents evidence on the amount of classroom variation in gains across various domains of achievement within the Tennessee Voluntary Pre-Kindergarten (TN-VPK) program; the data are taken from the randomized control trial (RCT) design of the TN-VPK evaluation. This study explores areas where those differences are largest, and offers…

As a result of the 1998 reauthorization of Head Start, the Department of Health and Human Services conducted a national evaluation of the Head Start program. The goal of Head Start is to improve the school readiness skills of low-income children in the United States. There is a substantial body of experimental and correlational research that has…