To the Editor:
A recent Inside School Research blog entry, excerpted in your Nov. 18, 2009, edition (“Betting on Head Start,” Blogs of the Week), reports that the reanalysis of the data of the HighScope Perry Preschool study by James J. Heckman and colleagues found a return on investment of from 7 percent to 10 percent, “better than zero, but not nearly as exciting as [the previously estimated] 16 percent or 17 percent.” Excitement about the findings of this study should come from its extraordinary validity, however, not from the necessarily imprecise estimates of its return on investment.
The reanalysis confirms and strengthens its validity by using rigorous statistical methods to counter methodological criticisms of the study, such as its small sample size, departures from random assignment, and testing of multiple hypotheses with the same data. Counter to recent claims, it proved that there is a substantial economic return for both boys and girls. This reanalysis also confirms previous findings that investment in a program like Perry is a great deal for taxpayers, because its return is greater than most investments’, including long-term investments in the stock market and investments in most components of the recent economic-stimulus package.
Lawrence J. Schweinhart
HighScope Educational Research Foundation
James J. Heckman
Henry Schultz Distinguished Service Professor of Economics
University of Chicago
A version of this article appeared in the January 06, 2010 edition of Education Week as Preschool Study’s Validity Trumps Money Implications