Experimental and quasi-experimental evidence on the impact of full-day kindergarten.

摘要

Nearly all school-age children in the United States attend kindergarten, but only 60 percent of kindergarten students are in full-day classrooms. As policymakers increasingly focus on the early childhood years as a critical period for establishing school readiness and remediating achievement gaps, one promising avenue for intervention in early childhood is through greater availability of full-day kindergarten. This dissertation relies on data from naturally-occurring experiments and quasi-experiments resulting from a policy change in Indiana that greatly expanded resources available for the provision of full-day kindergarten. While state grant funding increased availability of and access to full-day kindergarten across the state, the per-pupil funding allocation did not fully fund full-day provision for all and many school districts were unable to provide full-day kindergarten to all interested families and children. Because some school districts elected to employ student assignment procedures based on lotteries and fixed cutpoints on pre-kindergarten assessments, I am able to test the causal impact of full- versus half-day assignment on students' literacy skills at the end of the kindergarten year.;The first paper presents evidence from school districts in Indiana that used random lottery assignment in order to allocate oversubscribed full-day kindergarten slots. The results indicate that full-day assignment has a substantial, positive effect (0.31 standard deviations) when comparing students across treatment conditions within the same school. In particular, I find that low income students enjoy positive gains (0.34 s.d.) and nonwhite students benefit (0.52 s.d.) from full-day kindergarten in comparison to their half-day kindergarten peers. Hispanic students realize large full-day kindergarten effects (0.67 s.d.), and notably this impact is statistically different than that experienced by students who are not Hispanic. These heterogeneous treatment effects have implications for narrowing or closing the achievement gap early in formal schooling, and in fact the impact for Hispanic students constitutes 73 percent of the control group's end-of-kindergarten ethnicity gap. Using rough cost measures, a simple cost-effectiveness analysis suggests a range of effect sizes from 0.07--0.21 s.d. per thousand dollars of spending. Given the positive evidence on program effects, I discuss implications of the study design and findings for policy, including targeted versus universal provision of full-day kindergarten.;In the second study, I leverage exogenous variation in student assignment to full- and half-day kindergarten around a cutpoint on an assessment administered prior to kindergarten entry. This paper capitalizes on these discontinuities in the probability of treatment assignment to assess whether students in full-day kindergarten classrooms outperform their peers in half-day kindergarten settings as measured by literacy skills at the end of the kindergarten year. The regression-discontinuity design generates an estimate of the local average treatment effect (LATE) by comparing the outcomes of students above and near the cut-score (in half-day kindergarten) with those below and near the cut-score (in full-day kindergarten). I find that students in full-day kindergarten near the margin of interest do not outperform their half-day kindergarten counterparts, but given the imprecision of the estimates, I cannot rule out effects of the magnitude realized in the experimental study. Importantly, interpreting these findings in conjunction with existing evidence on full-day kindergarten as well as the lottery study evidence requires consideration of differential effects across the distribution of kindergarten entry literacy skills and by student characteristics, homogeneous versus mixed ability grouping of students, and peer effects under different student assignment policies.;In presenting the evidence on the impact of full-day kindergarten, this dissertation places these new findings in the context of an existing, observational literature on full-day kindergarten effects, extending and improving on that literature as the first papers to use exogenous variation in student-level assignment to identify full-day kindergarten effects. While the two papers test two different treatment conditions, the evidence is not inconsistent when taken in tandem. In the experimental settings, students received full-day kindergarten in the context of a mixed ability peer group while those in the regression-discontinuity districts participated in full-day kindergarten with a low-performing group of students homogeneously grouped by kindergarten readiness at school entry. The experimental evidence suggests that peer ability is also important---in addition to and complementary to full-day kindergarten participation---in determining individual student literacy skills at the end of the kindergarten year. The regression-discontinuity evidence does not replicate the strong positive effects of the lottery study, but given the large confidence intervals around the estimates of program impact, could be consistent. The experimental and quasi-experimental results are presented in turn, and the divergent findings are discussed in tandem. I suggest implications for policy based on this new evidence.