The long-term effects of early childhood education: what the evidence says

There is broad agreement in the literature on the value of early childhood education — but that agreement is usually reported as simpler than it is. Reading the evidence carefully reveals both its real strength and its limits.

What is found in the medium and long term

McCoy and colleagues' meta-analysis of 22 high-quality experimental and quasi-experimental studies conducted between 1960 and 2016 reports that participation in early childhood education is associated with significant reductions in special education placement and grade retention, and a significant increase in high school graduation. Effect sizes are moderate, and their percentage-point equivalents are policy-relevant.

Dietrichson and colleagues' systematic review of natural-experiment designs focuses on universal preschool. Findings on test scores and health and well-being measures are mixed, while effects on timely school progression, years of schooling, highest degree completed, employment and earnings are consistently beneficial. The same review reports larger benefits for children of low socioeconomic status.

Long-horizon follow-ups

Reynolds and colleagues followed more than 1,400 participants of the Chicago Child-Parent Center programme for twenty-five years. Participation was linked to higher educational attainment, income and socioeconomic status, and to lower rates of justice-system involvement and substance abuse. The same team's fifteen-year follow-up reports higher high school completion and lower juvenile arrest rates.

Barnett's classic review of 36 studies carries an early caution: programmes do not produce identical results. Short-term cognitive gains are common, while long-term effects vary markedly with programme quality. Quality is the variable at the centre of the debate.

The grey areas

The literature is not univocal, and pretending otherwise would be wrong. Gray-Lobe and colleagues, using admissions-lottery data in Boston, found increases in college attendance and high school graduation but no detectable impact on state achievement tests. Ansari, following thousands of children, reports partial convergence of the academic advantage during elementary school and a less favourable psychosocial picture associated with full-time, high-intensity attendance.

These findings do not contradict one another; they measure different things. A test score and a life trajectory are not the same indicator. Long-term effects are most consistent precisely where test scores are not: staying in school, graduating, working.

• Strong evidence: school continuity, graduation, reduced special education placement.
• Mixed evidence: durable advantages on standardised test scores.
• Decisive variable: programme quality — teacher quality, curriculum, family involvement.
• Largest benefit: for disadvantaged groups.

The right question is not “does preschool work?” What the evidence says is this: high-quality early childhood education works, and what quality consists of — from the teacher's interactions with the child to partnership with the family — is what actually decides the outcome.

References

• McCoy, D. C. et al. (2017). Impacts of early childhood education on medium- and long-term educational outcomes. Educational Researcher.
• Dietrichson, J. et al. (2020). Universal preschool programs and long-term child outcomes: A systematic review. Journal of Economic Surveys.
• Reynolds, A. J. et al. (2011). School-based early childhood education and age-28 well-being: Effects by timing, dosage, and subgroups. Science.
• Reynolds, A. J. et al. (2001). Long-term effects of an early childhood intervention on educational achievement and juvenile arrest. JAMA.
• Barnett, W. S. (1995). Long-term effects of early childhood programs on cognitive and school outcomes. The Future of Children.
• Gray-Lobe, G. et al. (2021). The long-term effects of universal preschool in Boston.
• Ansari, A. (2018). The persistence of preschool effects from early childhood through adolescence. Journal of Educational Psychology.