Researchers from five universities, led by the Harvard Graduate School of Education, analyzed 22 high-quality studies, which were conducted between 1960 and 2016. This meta-analysis found that children who attended high-quality early childhood education programs were less likely to be placed in special education, less likely to be retained in a grade, and more likely to graduate from high school than peers who didn’t attend such programs. The study is: Impacts of Early Childhood Education on Medium- and Long-Term Educational Outcomes 

The Washington State Institute for Public Policy (WSIPP) benefit-cost analysis examines, on an apples-to-apples basis, the monetary value of programs or policies to determine whether the benefits from the program exceed its costs. Its 2019 findings indicate early childhood programs have a 91% chance of benefits exceeding costs with the third highest total benefit in the PreK-12 results. Read the WSIPP State early childhood education programs: Universal results and State early childhood education programs: Low-income results for more information. 

Early Childhood Education Research Brief:

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Bania, N., Kay, N., Aos, S., & Pennucci, A. (2014). Outcome evaluation of Washington State’s Early Childhood Education and Assistance Program (Document No. 14-12-2201). Olympia: Washington State Institute for Public Policy.

Barnett, W.S., Frede, E.C., Mobasher, H., & Mohr, P. (1988). The efficacy of public preschool programs and the relationship of program quality to efficacy. Educational Evaluation and Policy Analysis, 10(1), 37–49.

Frede, E., Jung, K., Barnett, W. S., Lamy, C.E., & Figueras, A. (2007). The Abbott Preschool Program longitudinal effects study (APPLES): Interim report. New Brunswick, NJ: Rutgers University, National Institute for Early Education Research.

Hustedt, J.T., Barnett, W.S., Jung, K. & Thomas, J. (2007). The effects of the Arkansas Better Chance program on young children's school readiness. New Brunswick, NJ: Rutgers University, National Institute for Early Education Research.

Hustedt, J.T., Barnett, W.S., Jung, K., & Figueras-Daniel, A. (2009). Continued impacts of New Mexico pre-k on children's readiness for kindergarten: Results from the third year of implementation. New Brunswick, NJ: Rutgers University, National Institute for Early Education Research.

Lipsey, M.W., Hofer, K.G., Dong, N., Farran, D.C., & Bilbrey, C. (2013). Evaluation of the Tennessee voluntary prekindergarten program: End of pre-K results from the randomized control trial. Nashville, TN: Vanderbilt University, Peabody Research Institute.

Wong, V.C., Cook, B., & Jung, K. (2008). An effectiveness-based evaluation of five state pre-kindergarten programs. Journal of Policy Analysis and Management, 27(1), 122-154.

Xiang, Z., & Schweinhart, L.J. (2002). Effects five years later: The Michigan School Readiness Program evaluation through age 10. Ypsilanti, MI: High/Scope Educational Research Foundation.