This paper reviews research on the design and effectiveness of preschools in the United States. Three randomized controlled trials that enrolled roughly 350 total children in demonstration studies during the 1960s and 1970s shape much of the current discussion of preschool. We examine what these studies and more recent ones based on random…

Research has shown that teacher effectiveness is the most important school-based factor that influences student outcomes, including student achievement. Studies have also shown that there is substantial variation in teacher effectiveness, such that some teachers improve student outcomes at a much faster rate than others. The strong influence of…

Results from a cluster randomized trial of the impact of the Tools of the Mind pre-kindergarten curriculum on preschoolers' achievement, self-regulation, and social behavior are reported. Sixty classrooms with four-year-old children (N=877) were assigned to implement either the Tools curriculum (N=32 classrooms; 498 children) or the usual pre-k…