Early childhood education
The Perry Preschool Project

The Perry Preschool Project, which was conducted in the 1960s in Ypsilanti, Michigan, is the oldest social experiment in the field of early childhood education and has heavily influenced policy in the United States and across the globe. The experiment enrolled 128 three- and four-year-old African-American children with cognitive disadvantage from low-income families, who were then randomly assigned to treatment and control groups. The intervention for children in the treatment group included active learning preschool sessions on weekdays for 2.5 hours per day. The intervention also included weekly visits by the teachers to the homes of the children for about 1.5 hours per visit to improve parent-child interactions at home.

Initial evaluations of the Perry intervention showed that the preschool program failed to significantly boost an IQ measure. However, later evaluations that followed up the participants for more than fifty years have demonstrated the long-term economic benefits of the program, even after accounting for the small sample size of the experiment, flaws in its randomization procedure, and sample attrition. There is substantial evidence of large treatment effects on the criminal convictions of male participants, especially for violent crime, and their earnings in middle adulthood. Research points to improvements in non-cognitive skills, executive functioning, childhood home environment, and parental attachment as potential sources of the observed long-term impacts of the program. The intervention's many benefits also include improvements in late-midlife health for both male and female participants. Perry promoted educational attainment through two avenues: total years of education attained and rates of progression to a given level of education. This pattern is particularly evident for females. Treated females received less special education, progressed more quickly through grades, earned higher GPAs, and attained higher levels of education than their control group counterparts.

Research also demonstrates spillover effects of the Perry program on the children and siblings of the original participants. A study concludes, "The children of treated participants have fewer school suspensions, higher levels of education and employment, and lower levels of participation in crime, compared with the children of untreated participants. Impacts are especially pronounced for the children of male participants. These treatment effects are associated with improved childhood home environments." The study also documents beneficial impacts on the male siblings of the original participants. Evidence from the Perry Preschool Project is noteworthy because it advocates for public spending on early childhood programs as an economic investment in a society's future, rather than in the interest of social justice.
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