In yesterday’s Daily Journal column, John Hood argued that there is a case to be made for preschool programs that target low-income children.  He wrote,

Since the 1960s, several small-scale experiments have demonstrated the potential long-term benefits of intervening early in the lives of poor children who lack stable, two-parent families. Children who lack support at home tend to perform poorly in school, fail grades, and fail to graduate. Some of them, in turn, have children out-of-wedlock, become drug or alcohol abusers, become welfare recipients rather than workers, and enter the criminal justice system.

Hood observed that children from higher income and/or stable families usually receive little benefit from preschool interventions.  Thus, state lawmakers, who recently proposed changes to NC Pre-K eligibility requirements, had the right idea. North Carolina’s system of pre-kindergarten programs should focus on serving the needest kids.

A study published last week further supports Hood’s argument.  Elliot M. Tucker-Drob of the University of Texas at Austin published “Preschools Reduce Early Academic-Achievement Gaps: A Longitudinal Twin Approach” in the February 2012 issue of Psychological Science.   As a way to control for nature (genetic influences) and nurture (environmental influences), Tucker-Drob examined more than 600 pairs of identical and fraternal twins.

Coincidentally, John Hood has a twin brother, but I do not think they were part of the sample.

Anyway, Tucker-Drob found that preschool mitigated the effects of family environment among low-income children.  Yet, the benefits of preschool did not extend to (relatively) wealthier classmates.  According to the UT-Austin press release,

For children being raised in wealthier, and otherwise more advantaged, homes, there were no differences in tests scores between those who went to preschool and those who did not, Tucker-Drob found. But for children in disadvantaged homes, test scores were much higher if they went to preschool than if they stayed home.

In other words, changing NC Pre-K eligibility requirements to focus primarily on low-income children is a sound, research-based policy.