Can the Sustaining Environments Hypothesis Be Sustained? Testing Moderation of Sustained Public Preschool Benefits by Kindergarten Classroom Quality.

Mixed evidence over whether public preschool - Head Start and school-based public pre-k - confers an academic advantage beyond kindergarten has given rise to several explanations of variation in findings across studies. The "sustaining environments" hypothesis posits that for preschool attenders to maintain an advantage over preschool non-attenders, they must experience kindergarten classrooms of sufficiently high quality. Several studies have evaluated this hypothesis by testing whether preschool attenders benefit more than non-attenders from higher quality in their kindergarten classroom. They have produced mostly null findings but have commonly conceptualized the environment as instructional quality in kindergarten classrooms. We expand on this evidence base by testing for moderation of preschool impacts by instructional quality, along with the quality of two other key dimensions of kindergarten classrooms: the self-regulatory environment and the teacher-child relational environments. Moreover, we conduct this test using data on a diverse sample of students from low-income households who attended public preschool in Tulsa, OK, where preschool attendance has been associated with benefits that are sustained through elementary school. Findings suggest that associations between preschool attendance and first-grade outcomes are robust and mostly do not vary by subsequent kindergarten environments. Further tests of this hypothesis should examine variation in kindergarten environments between, rather than within, preschool evaluations. Researchers should also consider other reasons why some public pre-k programs produce more lasting impacts than others.