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

The National Institute for Early Education Research (NIEER) study compares 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. The study was designed to answer two primary questions: 1. What are the effects of the additional hours of preschool education offered by the extended-day, extended-year public preschool program on children's learning in literacy and mathematics by the end of the school year? 2. If learning gains from the program are evident for children by the end of one school year, are these gains sustained through kindergarten and beyond?