The work, published in this month's Journal of Labor Research, examined data from Ohio's 612 public school districts and figures on private school enrollment. Using a model developed by an Ohio University economist and lead author of the study, researchers made predictions on the influence of school competition on wages.

Although an increase in the number of both public and private schools would spark a salary increase, the model indicates a somewhat stronger impact from private school competition, says study author Richard Vedder, distinguished professor of economics at Ohio University. A private school environment might be a stronger draw than public school employment for some teachers, he says.

"Other things equal, a teacher is estimated to earn $808 more if there are a dozen public school districts in a county instead of one," the study authors wrote. Introduce a private school into a district where there was none and enroll 20 percent of the students, and the researchers' model predicts public teacher annual salaries would rise by $1,084. Combine the two -- a school system with 12 public school districts and 20 percent enrollment in private school -- and teacher pay would increase by $1,892 a year.

"The theory is that the more school districts compete for teachers, the more they'll have to pay to lure them," says Vedder, who published the study with former Ohio University graduate student Joshua Hall, now an economist with the Joint Economic Committee of the U.S. Congress.

Though the project focused on Ohio schools, drawing on data collected by the state Department of Education in 1996 and U.S. Census data from 1990, the results could have nationwide implications.

"I have a hunch -- and a pretty good one -- that the finding probably would hold if you tried to extend it to other states," Vedder says. "Ohio is so typical of the nation on every indicator in the study. We're right in the middle of teacher salaries among the 50 states."

The study analyzed what impact a number of factors -- such as private school enrollment, teacher experience and education level, class size and enrollment, per pupil expenditures and family income and education -- have on public teacher salaries. While the correlation between private school enrollment and higher wages wasn't as strong in low-income areas of the state, Vedder says, it was still significant.

Though private school teachers earn about 40 percent less than their public school counterparts, Vedder expects that the private school environment, which he says "has different rules and less bureaucracy," might draw public teachers. His study didn't analyze private teacher salaries, but he expects that competition would boost those wages as well.

Vedder, a former public board of education member who favors vouchers, acknowledges that private school supporters could use his study to win favor with teachers. "I think proponents of vouchers could take these results and talk to teachers and say, 'Look, vouchers aren't a threat to your well-being -- vouchers can improve your well-being because now you'll have more options of where you can teach,'" he says.

Despite this new information about teacher salaries, teacher unions still may have reason to campaign against vouchers, Vedder suggests. If more teachers opt for private school employment, he argues, union membership could fall, diminishing these organizations' political clout and union leaders' livelihoods. "I work with people in labor unions, and they're out fighting for their members, but they also want a good life for themselves," he says.

He also theorizes that even if public school teachers enjoyed higher salaries from private school competition, unions would argue that their members will lose in the long run. If union power dwindles, Vedder says, teacher organizations might have a hard time lobbying the legislature for wage increases, which would erode average salaries in education. And because Vedder's study doesn't forecast long-term salary trends, it remains to be seen how private school growth could impact paychecks in the big picture.