Early childhood interventions are often touted as powerful, cost-effective and equity enhancing investments. Indeed, in his State of the Union address, President Obama, highlighted the long-term impacts of high-quality early childhood interventions as the motivation for his administration’s heightened focus on preschool expansion. Critics, however, have been quick to point out that the observed benefits of many large-scale preschool interventions dissipate quickly. Most recently, results from the national Head Start Impact Study, a large, randomized trial, showed that at third grade, Head Start participants did not systematically outperform their control group peers on any of the developmental domains examined. In fact, many of the gains realized by participants at the end of the program year had eroded by kindergarten or first grade.

Earlier studies, including some of the most well-known experiments, have also noted a pattern of “fade out” for Head Start participants as well as preschool participants more broadly defined (Currie & Thomas, 2000; Deming, 2009; Lee & Loeb, 1995; Magnuson, Ruhm & Waldfogel, 2007). A number of explanations have been posited for these patterns. One plausible explanation children’s experiences in early elementary school have the potential to negate or perpetuate the initial benefits. Understanding the heterogeneity in treatment persistence is critical towards identifying strategies for early policy interventions with lasting impact. 

This study leverages two large, nationally representative datasets (Early Childhood Longitudinal Study, 1998 and 2010), to describe the extent to which preschool effects fade over time and to assess whether variation in fade-out patterns is related to observable characteristics of both the early childhood intervention itself as well as features of children’s early elementary school experiences. Earlier studies provide intuition on individual mechanisms that may lead to (or counter) fade out (e.g., Magnuson, Ruhm & Waldfogel, 2007b; Neidell & Waldfogel, 2010). In the current paper we provide a systematic exploration, considering fade-out patterns from kindergarten entry through eighth grade in ECLS-K and through first grade in ECLS-K:2010 on cognitive, social and behavioral outcomes.

The study characterizes the preschool intervention by “type” (e.g., Head Start, public preschool provided in schools, private centers) and “intensity” (age at enrollment and hours per week). We then explore whether fade out relates to children’s kindergarten and early elementary experiences. Specifically, do fade-out patterns depend on (1) full- versus half-day kindergarten enrollment; (2) density of peer participation in preschool; (3) alignment of pre-k and kindergarten experiences, and (4) kindergarten classroom quality. A key contribution of the current work is that we can leverage newly-available data to compare patterns of early fade out between cohorts of children who attended preschool in 1997 and in 2009, exploring how changes in fade out differ over a time period during which access to preschool programs grew rapidly and the context of kindergarten schooling changed pronouncedly.