Duncan and Sojourner look at the effects of the Infant Health and Development Program (IHDP) on later IQ and test scores of children from different income groups. Closing the gap should start as early as possible, they conclude. Based on data of baby’s born in 1980 they used statistical controls to use the random sample of infants that received the program to project its effects for low-income children across the United States as the original program included also children from higher-income children as it was based on birth weight.. They found that “the IHDP program boosted the cognitive ability of low-income children much more than the cognitive ability of higher-income children.” In fact, they projected that the program could—if made widely available to low-income families in the United States—”eliminate income-based gaps in IQ at age three.”

Do note that the effect did fade a bit with becoming older, but stayed significant (read also here).

This makes me think about this post I earlier wrote on investing in parenting support, but do note also this recent blog post.

Abstract of the research (You can download the paper here):

How much of the income-based gaps in cognitive ability and academic achievement could be closed by a two-year, center-based early childhood education intervention? Data from the Infant Health and Development Program (IHDP), which randomly assigned treatment to low-birth-weight children from both higher- and low-income families between ages one and three, shows much larger impacts among low- than higher-income children. Projecting IHDP impacts to the U.S. population’s IQ and achievement trajectories suggests that such a program offered to low-income children would essentially eliminate the income-based gap at age three and between a third and three-quarters of the age five and age eight gaps.