As enrollment in publicly funded preschool grows, many policymakers are asking, "Does publicly funded preschool work?" This question seems sensible: preschool programs, especially high quality ones, do not come cheap. An answer to this question could greatly aid decisions regarding continuing, expanding or abandoning investments in these programs.
Unfortunately, determining whether publicly funded preschool "works" is harder than it sounds.
Researchers have been asking some version of "does it work?" for nearly half a century and have generated an invaluable body of research which indicates that attending a preschool program is generally associated with good things for children. But in order to really understand whether publicly funded preschool "works," we must focus not only on the characteristics of the preschool programs themselves but also, perhaps counterintuitively, on what is happening outside of them. In other words, an equally important question to ask is this: how would children likely spend their days if these programs did not exist?
In the absence of publicly funded preschool, some families would find a way to ensure their children received the types of stimulating interactions and growth-promoting experiences that preschool can provide. Indeed, private for-profit and not-for-profit organizations have long supplied these types of experiences to families who can afford the sometimes hefty tuition bill. But for other children, the absence of publicly funded preschool could mean spending their days in very different types of care environments. Some of these children would be cared for by parents or other relatives. Others would spend their days in informal home-based childcare programs. Unfortunately, home-based programs tend to be less stimulating cognitively and less safe physically than formal center-based programs such as those provided in publicly funded preschools. When compared to children in center-based preschool programs, children in home-based programs spend more time watching television and less time reading with a caregiver or playing with games or puzzles. Children who attend informal home-based childcare programs develop fewer of the early academic or social skills that serve as a foundation for a successful start to elementary school.
In a study to be published in the Annals of Applied Statistics, we examine whether the impacts of a publicly funded preschool program differ depending on what children would have done in its absence. We focus on Head Start, the largest and oldest publicly funded provider of preschool services and compare the impact of attending Head Start for those children who, in the absence of Head Start, would have otherwise been in a home-based care setting to the impact on those who would have enrolled in some other center-based preschool program. Examining children's vocabulary skills, we find strong positive effects of Head Start for those children we predict would otherwise be in a home-based setting. By contrast, we find no evidence that Head Start confers additional benefits (at least, in terms of improved vocabulary) for those children we predict would otherwise attend some other form of center-based preschool. Thus the standard approach to answering the question of "does it work" can easily miss the mark. In the case of prior research on Head Start, the strong impacts for those children who would have otherwise been in a home-based setting are diluted by the lack of impacts for those children who would otherwise have been in a similar program.
The Better Questions: How do we Improve Preschool Programs and Ensure Access?
We do not need more evidence on whether publicly funded preschool "works" compared to no formal care--our study and numerous others (see here and here) provide convincing evidence that this is the case. The more important questions today are first, how do we ensure that all young children have access to high quality early childhood education, and second how do we make preschool programs better?
To be sure, preschool is no panacea. Even the highest quality preschool programs for three and four-year old children go only partway toward addressing the many challenges these children face when growing up in poverty. Nonetheless, attending a quality preschool program can help children develop the skills and habits of mind that support their success in early elementary school, when compared to lower stimulation home-care settings. And although some of the measured academic differences to peers without preschool do shrink over time, there is strong evidence of meaningful, long-term positive impacts of preschool on important indicators including high school graduation, health, employment, crime, and other outcomes.
We no longer engage in serious policy debates about whether children benefit from K-12 education. As a society, we have chosen to provide K-12 education to all our children, having recognized its tangible benefits to them and to society. We instead focus on how to improve children's K-12 school experiences. We carefully examine which curricula, pedagogies and supports lead to the strongest outcomes for children. When these interventions do not produce short or long-term impacts, we do not question the entire idea of K-12 education, but rather build on the evidence and ask how we can do better. This is how we should approach publicly funded preschool programs. Let's put to rest the question of whether preschool works, and focus on how to make sure all children can get it, and how to make it work better.
Todd Grindal is a researcher with Abt Associates where he studies how public policies impact young children and children with disabilities. @Grindato
Lindsay Page is an Assistant Professor of Research Methodology at the University of Pittsburgh School of Education. Her work focuses on quantitative methods and their application to questions regarding the effectiveness of educational policies and programs across the preschool to postsecondary spectrum. @linzcpage
Avi Feller is an Assistant Professor at the Goldman School of Public Policy, University of California, Berkeley. His research focuses on the intersection of statistics, data science, and public policy. @AviFeller
Luke Miratrix is an Assistant Professor at the Harvard Graduate School of Education. His research interests are primarily pertaining to causality with a focus on developing methodology to assess and characterize treatment effect heterogeneity.