A new study on the impacts of Pre-K in Tennessee has triggered the ongoing controversy about the effectiveness of early education. An article in the New York Times, Does PreK Make Any Difference? provides an analysis of several studies on Pre-K and its impact by David Kirp, a professor of public policy at University of California-Berkeley. Kirp argues that positive results are dependent on the quality of the early educations preschool children receive.
From my perspective, the preponderance of the research shows that quality early education for disadvantaged children results in sustainable positive results, as Nobel Laureate James Heckman economist shows in this infographic: