Findings of study supporting US school vouchers criticized

Data collecting company Mathematica Policy Research Inc is disputing what it calls exaggerated claims by Harvard professor Paul E. Peterson that the results of a study it recently conducted demonstrate the effectiveness of school vouchers in raising test scores for black students.

Mathematica collated test results of students in New York, Washington, DC and Dayton, Ohio as part of a study coordinated by Peterson aimed at evaluating the effect of voucher programs on educational performance.

In late August Peterson, an outspoken supporter of school vouchers, released results of the study, which he claimed showed significant improvements for students given vouchers to help attend private schools.

On September 15, Mathematica issued a press release rebutting Peterson's findings. It stated, “A new two-year study of low-income New York City students in grades 3 to 6 who received vouchers to attend private schools shows no significant difference in test scores between the scholarship and the control group.”

Peterson's claims received wide media publicity. His analysis purported to show that black students who switched from public to private schools with the help of vouchers made a statistically significant improvement in their standardized test scores for mathematics. The study measured test scores of 1,470 students given vouchers worth $1,700 a year, against those of a control group of students who applied but did not receive them.

Critics of Peterson's conclusions note that a large number of students offered vouchers in the study did not use them. Those that did use the vouchers tended to come from families with a higher level of income and education and were less likely to be on welfare. These facts were not included in Peterson's report.

Stanford professor of education and economics Martin Conroy commented, “I'm worried that there are all sorts of nonmeasurable characteristics of these kids that made it difficult for them to get into these private schools. Even if they got vouchers, they might not have been able to pay the other costs associated with private schools, and even if they could pay, they might not have been able to get into a private school.”

Peterson, director of the Harvard Program on Education Policy and Governance, is also a member of right-wing education think tank Hoover Institution's Koret K-12 Task Force. He is no stranger to controversial statistical analysis of children's' test scores on the effect of voucher programs on educational performance.

In the 1990s his rival evaluation of test result data for students involved in the Milwaukee Parents Choice Program, a voucher test case, were promoted by pro-voucher forces, and involved him in a polemic with John Witte, of the University of Wisconsin-Madison.

Peterson and others took Witte's data and re-assessed it, to come up with opposite results. Witte decried the statistical method used by Peterson's group, particularly the control group that the voucher or “choice” students were compared against, and concluded in 1997: “Based on the data, there is little evidence that voucher programs affect achievement.”

Many aspects of the latest controversy between Mathematica and Peterson contain echoes of the earlier dispute over the Milwaukee results. The Mathematica press release is headed “Voucher Claims of Success are premature in New York City: Second-year results show no overall differences in test scores between those who were offered vouchers and those who were not.”

David Myers of Mathematica, the principal investigator for the New York study, added: “If you ask the question, ‘When I offered students vouchers, did I make a difference in their test scores?,' right now you come away saying, ‘No, there's no impact.'

The statistical methods Peterson employed are once again under scrutiny. A group of academics called on him to release his data so that they can check the results, which were not peer-reviewed, but Peterson refused.

“The pressure to get something out at election time was a much more dominant theme than the idea of letting it go through review,” said one of the academics, Columbia University Teachers College professor Henry M. Levin.

The issue of school vouchers has featured in the US presidential campaign and there are initiatives on the ballot in California, Michigan and other states to permit the use of vouchers.

Support for vouchers is growing within sections of the Democratic Party. Clinton's former Secretary of Labor Robert Reich is now advancing a proposal for something he terms “progressive vouchers.” He calls for scrapping the entire current system of educational funding and replacing it with a voucher system tied to family income. The vouchers would range in value from $12,000 a year for students from the poorest families to $4,000 a year for children in more affluent circumstances. They would be redeemable at any school, public or private.

Defending his proposal Reich declared, “It's important to get central city kids out of public schools where social problems are concentrated,” Mr. Reich said. “Americans are segregated by income more than ever before. It is a huge and growing problem. We know that forced busing doesn't work. Using vouchers is the only way I see to solve the problem.”

Peterson also attempts to present his pro-voucher campaign as serving egalitarian ends. He claimed in 1999 that statistical data could prove “the potential of vouchers to achieve more racial and socioeconomic diversity in education—one of the great goals of education reformers since the 1960s” ( A Liberal Case for Vouchers, New Republic , Oct 4, 1999).

A look at voucher proposals on the November ballot hardly lends credence to such claims. The initiatives in California and Michigan are backed by extreme right wing forces. In California, Silicon Valley tycoon Tim Draper is the main financial backer of Proposition 38 that would directly subsidize better off families whose children already attend private schools. It would make available a $4,000 state funded voucher to any private school student, at an estimated cost of over $3 billion. The proposal would not prevent private schools receiving state aid from rejecting students on the basis of gender, language, religion or educational disability.

Amway Corporation President Dick DeVos is a major backer of a Michigan ballot initiative that would give $3,300 in public funds for students in targeted districts to attend private parochial schools. The measure is also being backed by the Michigan Catholic Conference.