Who Benefits Most from Head Start Programs?

The federal Head Start program is the largest early childhood education initiative in the United States, giving matching grants to preschool centers that provide parent training, early education, and health services to poor children and their families. Its goal is to increase educational achievement and reduce inequities in academic outcomes. New research on the impact of Head Start finds that participation in the program leads to large cognitive gains, particularly among children with the lowest initial cognitive skills. However, these gains do not typically persist after the culmination of Head Start participation.

Data for this research were gathered from the Head Start Impact Study, which follows a cohort of three-year-olds from pre-kindergarten through first grade. The sample of children is nationally representative, drawn from 84 regional Head Start programs at 353 individual centers. A central challenge to evaluating programs like Head Start is the inability to observe the counterfactual outcome for each child; researchers cannot directly observe how a child would have performed had she not attended the program.

The Head Start Impact Study randomly assigns offers of Head Start slots to children applying to oversubscribed Head Start centers, those with more applications than available spaces. The comparison group therefore comprises families that were not assigned spots, meaning they had to find care outside of the Head Start program, either from other centers or from informal sources. Random assignment eliminates the possibility that there are systematic differences between children who are offered spots in the program and those who are turned away, allowing researchers to provide an unbiased estimate of the impact of the program.

The researchers look at the difference in outcomes on cognitive assessments from the Peabody Picture Vocabulary Test (PPVT), which measures receptive vocabulary, and the Woodcock Johnson III, which measures early math and language acquisition. Cognitive tests such as the PPVT and Woodcock Johnson give results that compare children to average scores in particular cognitive domains. In most school districts, children are classified as “gifted” or “impaired” by the number of standard deviations they are from the average score.

The researchers found that participation in Head Start increased test scores on the PPVT by an average of 0.27 standard deviations for all participants during the pre-school period. Among the lowest-skilled participants, defined as those in the bottom quintile of baseline scores on the PPVT and Woodcock Johnson, scores increased within a range of 0.32 to 1 standard deviation. Typically, anything between 1.5 to two standard deviations below the average might qualify a student to be designated “impaired,” suggesting that such gains are dramatic. A similar impact is found for scores on the Woodcock Johnson. These test score gains occurred only while participants were enrolled in Head Start; they did not persist after the program had ended.

The focus on oversubscribed Head Start centers is both a benefit and a limitation of this research. Oversubscription allows for the randomization of participants into two groups, a critical component of creating an unbiased estimate for the impact of participation. However, one area for future researchers to consider is whether the gains from Head Start seen in this study would persist in centers that are not oversubscribed. It may be the case that centers become oversubscribed due to word of mouth about their effectiveness—if this is true, it is not obvious that the same dramatic benefits from Head Start would be observed in other settings.

This study contributes to a growing body of research suggesting large short-term gains from Head Start participation. Critically, it finds that participants with the lowest initial skills are the most likely to benefit, an exciting aspect of a program intended to reduce inequitable academic outcomes. However, the lack of observable long-term gains from Head Start remains a serious issue for policymakers to consider. Future research that focuses on the transition from Head Start to elementary school would provide valuable insights for those attempting to understand how early gains from Head Start can be sustained.

Article Source: Experimental Evidence on Distributional Effects of Head Start. Marianne Bitler, Hilary Hoynes, and Thurston Domina.  National Bureau of Economic Research, 2014.

Feature Photo: cc/(christielockwood)