Is More Better ? The Effects of Full-Day vs. Half-Day Preschool on Early School Achievement Executive

Abstract

What is less well established, however, are the benefits children derive from programs of various durations and intensity. Preschool programs vary greatly—from less-than-half-day to full-day-plus programs. Little rigorous research is available to inform policy decisions about the relative benefits of programs with shorter and longer hours per day or days per year. To address this need, NIEER conducted a randomized trial in which 4-year-olds in a low-income urban district were randomly assigned to programs of different durations. The programs were otherwise quite similar: all had teachers with college degrees, a low ratio of children to teachers, and used the same curriculum. Our study compared 85 children assigned to an 8-hour program for 45 weeks to 254 children assigned to a 2.5-to 3-hour program for 41 weeks. Due to the limited number of spaces available in the 8-hour extended year program, a lottery was used to determine entry, providing the basis for random assignment. Such studies are the " gold standard " approach to addressing cause and effect questions in education research. The district's residents were 50 percent Hispanic, 21 percent African-American, and more than 20 percent of the families lived in poverty.