When does 1 + 1 not equal 2? The relative advantage of public school-based pre-k versus head start for low-income children's kindergarten cognitive and self-regulatory skills.

Decades of research suggest that both Head Start and public pre-kindergarten (pre-k) programs boost low-income preschoolers' kindergarten skills. What is not yet well understood is whether there are relative advantages of transitioning from Head Start after 1 year into a school-based public pre-k program for the year immediately before kindergarten for children's developing cognitive and self-regulation skills. This is an important question, because in many communities Head Start and school-based pre-k programs provide competing early education options for low-income 4-year-olds, leaving policymakers, educators, and parents wondering which pathway best promotes the mix of skills predictive of success in elementary school.