Is full better than half? Examining the longitudinal effects of full-day kindergarten attendance

Kindergarten policy varies widely both across and within states. As high-stakes testing become more important, more attention is being paid to the delivery of early education, and more states and districts are considering moving to full-day kindergarten to increase the educational attainment of students. This paper uses the Early Child Longitudinal Study-Kindergarten Cohort to evaluate the efficacy of this policy. In ordinary least squares, probit, county-fixed effects, and instrumental variable models, we find that there are initial benefits for students and the mothers of students that attend full-day kindergarten, but that these differences largely evaporate by third grade. The only effect of full-day kindergarten attendance on boys is to increase the prevalence of severe external behavioral problems, whereas there is some evidence that girls who attend full-day kindergarten have increases in math scores that persist through third grade. Finally, attending full-day kindergarten is found to have no additional effect on students in families with income below the poverty threshold, despite claims by some advocates that full-day programs are beneficial for the most disadvantaged students.