At the recent Education Writers Association conference on early childhood education, Russ Whitehurst of the Brookings Institution cited Tulsa and Boston studies as evidence that the benefits of early childhood education are much greater for low-income children than for middle-class children.

This is incorrect. The Tulsa and Boston studies actually provide evidence that the benefits of early childhood education are only modestly less for middle-class children than for lower-income children. In Tulsa, the research, in a paper on which I was a co-author, suggests that the test score boost from full-day pre-K for middle class children is about 88% of the boost for lower income children. In Boston, Weiland and Yoshikawa’s research suggests test score benefits of Boston’s full-day pre-K program for middle-class children are 71% of the benefits for lower-income children.

These test score benefits for middle-class children are sufficient to predict adult earnings gains that will be many multiples of costs. The Tulsa study calculates that the ratio of the present value of future adult earnings benefits to program costs for full-day pre-K is 2.82 for middle-class children, which is only modestly less than the 3.09 ratio for children eligible for a free lunch.  For Boston, my analysis of Weiland and Yoshikawa’s findings suggest that the ratio of the present value of future adult earnings benefits to costs for Boston’s full-day pre-K program is 2.30 for middle class children, versus 3.22 for children eligible for a subsidized lunch.

A key point in both findings is that the ratio of predicted future adult earnings benefits for middle class children to program costs is much greater than one. Providing free, high-quality pre-K to middle class children can be rationalized because economic benefits exceed costs. Universal pre-K may also win middle-class votes and support, but universal pre-K can be rationalized on its economic merits rather than just on political expediency.

I know of no other evidence that allows a direct comparison of the relative benefits of pre-K for middle-class and lower-income children. There is one study of pre-K for middle-class children in Utah that shows some benefits.

There might be various reasons why the social benefits of pre-K for lower-income children are much greater than for middle class children, even if the dollar earnings benefits are similar. Lower-income children would be predicted to have baseline adult earnings that are lower, so a similar dollar benefit will be a larger percentage boost to adult earnings.  In Tulsa, our study predicts that the percentage boost to adult earnings for children eligible for a free lunch is over 10%, whereas the percentage boost for middle-class children is between 5 and 6%. We might judge that providing extra dollars to lower income children is more valuable because it has a more dramatic impact on their future well-being.  In addition, it is a plausible hypothesis that pre-K may have greater benefits in reducing crime and welfare usage for children from lower-income families than for middle-class children, although I know of no empirical evidence for or against such greater relative benefits.

For child care programs, Duncan and Sojourner’s study of the Infant Health and Development program suggests that this program only boosts test scores for lower-income children. For parenting programs, studies of the Nurse Family Partnership suggest that NFP only works for lower-income families, not middle-class families.  Pre-K may be different from child care and parenting programs because pre-K may provide social and cognitive learning in a group setting that is hard for many middle class families to duplicate on their own.

The evidence is sparse on the absolute and relative benefits of early childhood education for middle-class children. This evidence is always likely to be sparse because there is not great interest from government or the philanthropic community in sponsoring extensive research on how early childhood education affects the middle class.  But the available evidence provides some economic support for universality in pre-K programs, while the pattern of benefits for children would argue for targeting child care and parenting programs on lower-income families.  Considering how programs benefit parents might alter these calculations for relative benefits and costs for different income groups, and is an important topic for future research.