A careful review of the Brookings study of New York City’s privately-funded voucher program finds that the program had no significant effects.

The authors of the voucher study, Paul Peterson of Harvard and Matthew Chingos of Brookings, wrote an article in the Wall Street Journal claiming that their study proved “the success” of vouchers. The study was widely cited by news media and voucher advocates as “proof” that vouchers improve college-admission rates for minority students.

Sara Goldrick-Rabb of the University of Wisconsin says that the study does not confirm the authors’ inflated claims. The National Education Policy Center, which published Goldrick-Rabb’s review, writes:

In her review of the Brookings report, Goldrick-Rab observes that the study identifies no overall impacts of the voucher offer, but that the authors “report and emphasize large positive impacts for African American students, including increases in college attendance, full-time enrollment, and attendance at private, selective institutions of higher education.”

This strong focus on positive impacts for a single subgroup of students is not warranted. Goldrick-Rab notes four problems:

· There are no statistically significant differences in the estimated impact for African Americans as compared to other students;
· There is important but unmentioned measurement error in the dependent variables (college attendance outcomes) affecting the precision of those estimates and likely moving at least some of them out of the realm of statistical significance;
· The authors fail to demonstrate any estimated negative effects that could help explain the average null results; and
· There are previously existing differences between the African American treatment and control groups on factors known to matter for college attendance (e.g., parental education).

“Contrary to the report’s claim, the evidence presented suggests that in this New York City program, school vouchers did not improve college enrollment rates among all students or even among a selected subgroup of students,” Goldrick-Rab writes.