Skip to main content

What Does the Research Really Say About Preschool Effectiveness?

Strong evidence shows high-quality preschool works; now it’s time to focus on creating more high-quality programs
Cover photo for Untangling the Evidence on Preschool Effectiveness: Insights for Policymakers

Untangling the Evidence on Preschool Effectiveness: Insights for Policymakers

PALO ALTO, CA —Students who attend high-quality preschool programs reap benefits that can last through school and their lives, according to a review of research released today by Learning Policy Institute (LPI). The study includes reviews of rigorous evaluations of 21 large-scale public preschool programs which find that children who attend these programs are more prepared for school and experience substantial learning gains in comparison to children who do not attend preschool.

Research on early learning programs in the 1960s and 1970s revealed that  benefits for children lasted into adulthood, inspiring many states to invest in preschool programs. However, recent evaluations of two programs—Tennessee’s Voluntary Pre-K program and Head Start—found mixed results, leaving policymakers and the public confused about whether or not investments in preschool programs actually do make a difference to student success.

LPI’s new report reviews these two studies and others in depth, noting that interpretations of the results often depend on the groups of students being compared. When participants are compared to others who attended similar preschools – or to a more generally advantaged comparison group – there are often not strong differences in their elementary school performance.  This does not mean preschool effects “fade out” or that preschool is not effective; it means that the children in both groups benefit similarly.

On the other hand, when participants are compared to very similar students who did not attend preschool, the benefits of participation are  found to be substantial.  Both preschool and elementary school quality also make a difference for the strength of ongoing effects in terms of achievement, school progress, and attainment. 

LPI’s researchers found that investments in quality preschool programs bolster student success. Students who attend preschool programs are more prepared for school and are less likely to be identified as having special needs or to be held back in elementary school than children who did not attend preschool. Studies also show clear positive effects on children’s early literacy and mathematics skills.

The review affirms the short- and long-term benefits of many preschool programs and makes recommendations for how policymakers can implement and support high-quality programs.  

"The research suggests that the main issue is not whether preschool works but how to design and implement effective preschool programs that deliver on their promise," said Linda Darling-Hammond, President of LPI. Research finds that preschool programs that demonstrate the strongest and most persistent positive effects employ well-qualified educators, use a developmentally appropriate program, and provide adequate learning time for students. In order to achieve sustained benefits from preschool, districts and states should invest in the essential building blocks of high-quality early childhood education, including teacher preparation, thoughtful curriculum, meaningful family engagement, and support for English learners and students with special needs.

Although these elements can be expensive, “when well-implemented and supported by subsequent schooling, high-quality preschool can pay for itself. Studies of high-quality programs that have followed students into adulthood find up to $17 returned in social benefits for every dollar invested. This is because people who attend preschool are more productive in school, work, and society generally—with higher levels of education and earnings, less involvement in delinquency and crime, and fewer chronic health problems,” said W. Steven Barnett, Founder and Senior Co-Director of the National Institute for Early Education Research (NIEER) at Rutgers University.

“Even when students are only followed into elementary school, studies find significant benefits from preschool in lower rates of grade retention and special education that offer a partial return on the investment. High-quality preschool programs can also help close the gap in school and life outcomes between those raised in low-income families and their wealthier peers,” Barnett said.

“Quality doesn’t just happen,” said lead author Beth Meloy. “You have to design for it, support it, and continually work for it. States that are serious about providing high-quality early learning opportunities have focused their attention on setting clear expectations for educators’ knowledge and skills, supporting educators to reach those expectations, and establishing mechanisms for ongoing program improvement."

The report was released at an invitation-only reception in Sacramento, convened by the Learning Policy Institute and New America, and is authored by Beth MeloyMadelyn Gardner, and Linda Darling-Hammond.


About the Learning Policy Institute

The Learning Policy Institute conducts and communicates independent, high-quality research to improve education policy and practice. Working with policymakers, researchers, educators, community groups, and others, the Institute seeks to advance evidence-based policies that support empowering and equitable learning for each and every child. Nonprofit and nonpartisan, the Institute connects policymakers and stakeholders at the local, state, and federal levels with the evidence, ideas, and actions needed to strengthen the education system from preschool through college and career readiness.