I'll just admit up front that the vast inequities that exist even before children start school bother me, and that I am predisposed to favor programs that would help disadvantaged children early in life. Thus, I was delighted when Head Start announced some years back that it was going to carry out a randomized control trial--that is, to assign some preschool children randomly to Head Start and others not--so that it would be possible to do a statistically meaningful test of how well Head Start worked. I presumed that the test would provide ammunition for my pre-existing views.
But as the evidence has built up, Head Start is failing its test. The latest evidence appears in the "Third Grade Follow-up to the Head Start Impact Study: Final Report," which was released in December. The report was carried out by a company called Westat and published by the Office of Planning, Research and Evaluation, Administration for Children and Families, U.S. Department of Health and Human Services. Basically, the report shows that Head Start provides short-term gains to preschool children, but those gains have faded to essentially nothing by third grade.
To appreciate how depressing this conclusion is, you need to appreciate the high quality of the study. It's based on a nationally representative sample of more than 5,000 3 and 4 year-olds from low-income families who were eligible for Head Start. These children were randomly either assigned to Head Start, or not. Data collection started in 2002, and so by 2008, data was available on how the children were performing in third grade. The study didn't just look at test scores: it considered a range of data on how Head Start might affect aspects of cognitive development, social-emotional development, health status and services, and even parenting practices.
The findings are summarized in this way: "In summary, there were initial positive impacts from having access to Head Start, but by the end of 3rd grade there were very few impacts found for either cohort in any of the four domains of cognitive, social-emotional, health and parenting practices. The few impacts that were found did not show a clear pattern of favorable or unfavorable impacts for children."
Of course, because I am predisposed to favor these kinds of programs, I look for silver linings. Perhaps for certain specific subgroups such preschool programs can be useful? Perhaps certain kinds of curriculum are more likely to make a lasting difference? Perhaps helping children from low-income families catch up before they start school is insufficient, but a sustained set of interventions continuing through elementary school would show lasting results? Sometimes studies of early preschool interventions have found little
gain in measured outcomes a few years into school, but later gains like
greater rates of high school completion or reductions in certain risky
behaviors in adolescence. Maybe as the Head Start study continues, these
sorts of longer-term gains will emerge?
I don't have an answer here. Some years ago, I edited a paper in a special issue of the Future of Children about the enormous gaps in school readiness for preschool children. Equal opportunity is an important goal of public policy, and as a society, we are clearly not providing equal opportunity to many children--who are already well behind before their first day of school. If the Head Start study had positive results about the long-run efficacy of preschool programs, I'd trumpet it to the hills. But the unfolding evidence isn't backing up the conclusion I would prefer.