Society for Research in Educational Effectiveness (SREE) Conference
Theme: Tensions and Tradeoffs: Responding to Diverse Demands for Evidence
March 6-9, 2019
Title: A Reanalysis of Impacts of the Tennessee Voluntary Prekindergarten Program (Paper)
Authors: Tyler Watts, Greg Duncan, Mariela Rivas
The evidence base on preschool programs is large and growing, but we severely lack evaluations of preschool programs that use experimental designs. Most of the current research reporting long-run preschool effects has depended on non-experimental or quasi-experimental designs, leaving questions as to whether the widespread scale-up of public preschool should be expected to produce long-lasting effects on children’s lives. The Tennessee Voluntary Prekindergarten Program (TNVPK) was recently evaluated with a lottery-based random assignment design (Lipsey, Farran, & Durkin, 2018). However, study evaluators made a number of analytic decisions that were not typical of the standard program evaluation techniques found in the economics literature. In particular, Lipsey and colleagues (2018) defined the “treatment group” in a way that adjusted for enrollment in non-study sites, opening the door for potential selection bias. Further, although random assignment was conducted at the site level, Lipsey and colleagues did not control for site fixed effects, raising questions as to whether reported effects could be due to between site differences that should be controlled. We provide an independent re-analysis of TNVPK data, relying on econometric approaches to estimating the effects of TNVPK. We examine the ITT impacts of the opportunity to enroll in TNVPK on a host of child outcomes measured through the end of third grade, and we also address issues surrounding non-compliance, attrition, site heterogeneity, and fadeout through a number of additional analyses. Despite employing different analytic approaches, our findings largely confirm the results reported by Lipsey and colleagues (2018) and suggest that more careful evaluation work is needed if pre-k programs implemented at scare are expected to produce positive long-term outcomes.