Head Start Impact Study

Summary

The Head Start Impact Study is one of the most politically contentious education evaluations in US history. Children gained meaningfully during the Head Start year—reading skills, vocabulary, attention. But by first grade, the cognitive gains had largely faded to insignificance. Critics cited this as evidence of Head Start's ineffectiveness. Defenders noted that children subsequently attended the same low-quality schools, erasing gains that high-quality K–12 could sustain. Health and parenting outcomes did persist. The debate over 'fade-out'—whether gains from early programs disappear or are masked by poor subsequent schooling—remains active, making this study essential context for any early childhood policy discussion.

Research question

"What is the causal impact of access to Head Start on children's cognitive, social-emotional, and health outcomes?"

Methodology

Result

Mixed

Age 3 cohort: meaningful reading/literacy gains by end of program year; by 1st grade: no significant cognitive differences; 3rd grade follow-up: minimal lasting impacts; some positive health and parenting effects persisted

Evidence strength

Moderate

Randomized trial; replication status unknown or limited.

Replication status

N/A