WASHINGTON - Because three of four members of the combined presidential tickets favor some form of vouchers for students in troubled schools, fresh scrutiny on the issue appears imminent.

The research record for two public voucher programs in Cleveland and Milwaukee and three private programs in Dayton, Ohio; New York City; and Washington, D.C., shows the programs have some promise.

"The consensus among the evaluators is there are some academic benefits," said Jay Greene, who summarized the research on the five programs in a Manhattan Institute report released in July. "What is in dispute is the magnitude of the benefits."

The programs are small, have limited track records and show only modest gains academically.

"We're having a ferocious public policy debate about something that doesn't even register on the Richter scale," said Bella Rosenberg of the American Federation of Teachers.

However, the debate about vouchers is unlikely to fade, especially with the fresh political attention.

Parents whose children are in chronically failing schools should receive their share of federal school aid as a lump sum to be used for private-school vouchers, said Texas Gov. George W. Bush, the Republican presidential nominee.

"In my administration, federal money will no longer flow to failure," he said.

Vice presidential candidate Dick Cheney made his views clear during his acceptance speech at the GOP convention.

"For all their sentimental talk about children, Clinton and Gore have done nothing to help children oppressed by bureaucracy, monopoly and mediocrity," Cheney said.

Sen. Joseph Lieberman of Connecticut, who is expected to be nominated as the Democrats' vice presidential candidate Wednesday, has favored a voucher experiment.

Endorsing a book on school choice, Lieberman wrote, "Competition in schoolyards and athletic fields across our country has built stronger minds and bodies and greater self-esteem for generations of American children. Isn't it time we applied those lessons indoors to improve our ailing education system through competition and offer more choices to parents and kids trapped between the rock of the status quo and the hard place of waiting for the needed reform of public schools?"

That leaves only Vice President Al Gore as a voucher foe.

"I'm not for vouchers," Gore said in a recent campaign appearance, adding, "I'm not afraid to have a vice president who disagrees with me on some issues."

The question of whether vouchers work is in the hands of researchers.

Aside from public programs in Milwaukee and Cleveland, Florida has a fledgling public voucher program. Across the country, 79 privately financed scholarship programs are in place although most of the research has focused on the private programs in Dayton, New York, and Washington.

So far, the debate among those researchers has been rife with partisan sniping.

The irony is that the quality of research aimed at voucher programs is far higher than most education research. Only rarely do education researchers use the reliable tools of medical researchers, where studies focus on two groups - the treatment group getting the medicine and the control group getting the placebo.

But the small-scale voucher experiments lend themselves to that type of research.

First-year results from the private scholarship programs in Dayton and Washington showed the largest gains among elementary students.

In Dayton, children entering a private school in grades two to eight outscored their counterparts by seven points in math and five in reading, according to a report released in February by Paul Peterson, director of Harvard's Program on Education Policy and Governance.

"A voucher program, it now turns out, is probably going to be more successful if it begins with kids early on," Peterson said.

Voucher opponents accuse Peterson, who speaks in favor of voucher programs, of conducting biased research.

"The research is flawed," said Ed Muir of the American Federation of Teachers. "There are significant selection effects going on."

Muir said the programs in Cleveland, Dayton and Milwaukee have a religious bias because Catholic families are more likely to end up in the programs.

Evidence also shows that the mothers of children in voucher programs are better educated than the mothers of children who remain in public schools, Muir said.

That's to be expected, Greene said.

Any program aimed at disadvantaged families is more likely to help the better educated of the poor- mothers with their act together - he said. Researchers can control for that.

Despite small differences in maternal education, studies of the five voucher programs found no evidence that better-off students end up with vouchers, Greene said.

George Mitchell, a consultant at a pro-voucher think tank at Milwaukee's Marquette University, said he sees no evidence that Catholic schools favor Catholic children.

"The Milwaukee program allows no choice school to use any screening criteria," he said. "The only way you can get turned down is if there is no space, there's a lottery, and you lose."

One researcher who attempts to be evenhanded about voucher results is Henry Levin from the National Center for the Study of Privatization at Columbia University in New York City.

He sees voucher programs as consistently positive.

"But the bad news is it's quite small," Levin said.

Reforms in public schools have far more impact, he said. For example, in a study -of reforms in Memphis, Tenn., schools using the Success for All reading program saw their students' standardized test scores jump from the 30th%ile, where 70% of students nationwide had better scores, to the 56th%ile, above average.

So far, vouchers' effects have been a fraction of that, he said.

Mitchell dismisses criticisms that reforms such as Success for All or reducing class size produce bigger gains than vouchers.

"There are a lot of intellectual gymnastic games being played," said Mitchell, who said many private schools adopt the same reforms. He sees a combination of alternatives working.

"Maybe we could do small class sizes and have lots of choice."