A Princeton University researcher has waded into the debate over the effectiveness of school vouchers in Milwaukee, concluding that math scores have risen substantially for the students in the program.
In several different analyses of test scores, Cecilia E. Rouse concluded that students who enrolled in private schools under the program scored better in math than students in the city’s public schools.
Two previous studies of the first-of-its kind program, which provides public money for low-income students to attend private schools, differed sharply with each other in their conclusions.(“New Studies on Private Choice Contradict Each Other,” Sept. 4, 1996.)
Ms. Rouse, an assistant professor of economics and public affairs, said that in her analyses she tried to correct the flaws in both of those studies and to avoid any ideological bias.
“I don’t really have a political ax to grind when it comes to school choice,” she said in an interview last week. “I want to see what works for kids.”
But Ms. Rouse cautioned that the Milwaukee program, which serves about 1,600 students, is too small to allow any broad conclusions. And she said many of the data were missing or incomplete.
“While my analysis suggests that the results are robust,” she wrote, “my strategies cannot substitute for better data.”
One previous study, led by researchers Paul E. Peterson of Harvard University and Jay P. Greene of the University of Houston, concluded that the program raised math and reading scores significantly for children who were enrolled in private schools at least three years.
Another set of studies by John F. Witte, a professor of education at the University of Wisconsin-Madison, found no significant gains in test scores.
No Reading Gains
In one set of analyses, Ms. Rouse compared test scores of students who used the vouchers to enroll in private schools with those of nonselected applicants who remained in the public schools.
That approach was similar to the analyses conducted by Mr. Peterson and Mr. Greene. The key difference is that the previous study did not include students who were selected for the program but never enrolled or who subsequently left the private schools and returned to the public schools. Some critics argued that those omissions biased the earlier study, since students who were not being well-served by the private schools were more likely to leave.
Ms. Rouse then compared the voucher students with a group of students in the city’s public schools, as Mr. Witte had done. Critics of his studies suggested that the students in the public schools were better off economically than the students who participated in the voucher program, and that the difference may have influenced his findings.
Although Mr. Witte tried to control for differences in family income, critics contended that he did not do so adequately.
Ms. Rouse sought to eliminate such background factors by comparing each student against his or her own test scores over time.
Under both analyses, she concluded that the math scores of students in the private schools likely increased by 1.5 to 2 percentage points each year over what they would have been had those students remained in public schools. But the results for reading were mixed and not statistically significant.
Bruce Fuller, an associate professor of public policy and education at the University of California, Berkeley, said the new study “is definitely a corrective on the grand claims that Paul Peterson and Jay Greene were making last fall.”
But he said the findings say more about the quality of the three private schools attended by most choice students than about the program overall.
