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Preschool Impact Studies

HighScope Perry Study

Lifetime Effects: The HighScope Perry Preschool Study

Through Age 40 (2005)


This study—perhaps the best-known of all HighScope research efforts—examines the lives of 123 African Americans born in poverty and at high risk of failing in school.

From 1962–1967, at ages 3 and 4, the subjects were randomly divided into a program group that received a high-quality preschool program based on HighScope's participatory learning approach and a comparison group who received no preschool program. In the study's most recent phase, 97% of the study participants still living were interviewed at age 40. Additional data were gathered from the subjects' school, social services, and arrest records.


The study found that individuals who were enrolled in a quality preschool program ultimately earned up to $2,000 more per month than those who were not.


They also were more likely to:

• Graduate from high school

• Own homes

• Have longer marriages

• Commit fewer crimes



Abecedarian Project

The Abecedarian Project, initiated in 1972, provided educational child care and high-quality preschool from age 0-5 to children from very disadvantaged backgrounds (most raised by single mothers with less than a high school education, reporting no earned income, 98% of whom were African-American).


Child care and preschool were provided on a full-day, year-round basis; had a low teacher-child ratio (ranging from 1:3 for infants to 1:6 for 5-year-olds); and used a systematic curriculum of “educational games” emphasizing language development and cognitive skills. The average annual cost of the intervention was about $13,900 per child (in 2002 dollars).


This program was evaluated in one randomized controlled trial of 111 participating children, followed through 21 years of age. The children were randomly assigned to one of four groups, in which they received:

i. The child care/preschool treatment (age 0-5) alone

ii. The child care/preschool treatment (age 0-5) and the school age treatment (grades 1-3)

iii. The school-age treatment alone

iv. No treatment (this group could and often did use other child care and preschool resources available in the community.)

Effects of the Abecedarian Project

The study found that educational and life outcomes for the children receiving the child care/preschool treatment (groups (i) and (ii) ) were much superior to outcomes for the children not receiving the child care/preschool (groups (iii) and (iv)). The results are summarized below. By contrast, the school-age treatment alone had only a marginal impact (results not summarized here).


Impact of child care/preschool on reading and math achievement, and cognitive ability, at age 21:

• An increase of 1.8 grade levels in reading achievement

• An increase of 1.3 grade levels in math achievement

• A modest increase in Full-Scale IQ (4.4 points), and in Verbal IQ (4.2 points).

• Impact of child care/preschool on life outcomes at age 21:

• Completion of a half-year more of education

• Much higher percentage enrolled in school at age 21 (42 percent vs. 20 percent)

• Much higher percentage attended, or still attending, a 4-year college (36 percent vs. 14 percent)

• Much higher percentage engaged in skilled jobs (47 percent vs. 27 percent)

• Much lower percentage of teen-aged parents (26 percent vs. 45 percent)

• The study also found suggestive evidence of a reduction in criminal activity, but because of the small sample size, most of these effects were not statistically significant.

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