After a series of failed efforts to set up a merit pay system for public school teachers, Chancellor Joel Klein could turn next to private funders.

In past contract talks with the United Federation of Teachers, Mr. Klein has been unable to convince teachers to change their contract to include a differentiated pay system for individual teachers based on performance, and the union has steadfastly opposed the plan.

Last summer, the Department of Education tried another tactic, quietly applying for a federal program, the Teacher Incentive Fund, which subsidizes merit pay programs. The application, filed in partnership with a private group, New Leaders, was rejected and the city is not reapplying this spring.

But last week, Mr. Klein said he hasn’t yet given up his goal to pay teachers based on merit — which could be measured in whole or in part by student test scores — not seniority.

“My views on this are clear. I think people that perform well ought to be rewarded,” he told reporters Thursday. “We have to work with the UFT, but I’ll look at the variety of options as we go forward.”

With the teachers union not expected to support him, however, one of the only options the chancellor may have left to get the program funded and skirt the union’s opposition is to use money from private groups — a strategy he has often relied on to jump-start projects. Other cities around the country have used a similar tactic to start merit pay programs, including Denver, a place Mr. Klein said he is studying.

“We’re looking at the experience throughout the United States. Denver has a model. There are people in Texas that are doing this,” he said. “I’ll continue to explore our options.”

The merit pay system in Denver — whose school superintendent, Michael Bennet, has met with Mr. Klein — was set up first as a pilot program at a small number of schools with $1 million from the Broad Foundation and $9 million in other local donations. The program, known as the Professional Compensation System for Teachers, was then expanded throughout the city and is now financed with taxes, although to avoid a clash with the teachers union, teachers were not required to join. Instead, they were given the option to add merit-based components to their annual salaries that could lead to bonuses, including teaching at a challenging schools and meeting benchmarks for student achievement.

Mr. Bennet’s senior academic adviser, Brad Jupp, who oversees the program, said Denver’s plan worked mainly because teachers bought into it.

“I am pro-labor partisan. I believe that having labor as partnership makes the transition easier — it takes some of the controversial pop out of this controversial issue,” he said, though he added: “If labor’s in the way, there are ways to make alternative pay work in school districts that might prove the concept less controversial over time.”

One of those ways could be a pilot program begun with philanthropic money, he said.

In New York, however, “labor” says it plans to get in the way of any individual merit pay plan Mr. Klein proposes. The UFT maintains that legally, any changes to teacher pay rates would have to be negotiated with the union first, and its president, Randi Weingarten, has said she opposes any merit pay system that would replace or supplement the current seniority-based pay scale for teachers in the city.
“Instead of merit pay schemes, which have never worked anywhere they have been tried, we should be working together on ways to improve the graduation rate,” Ms. Weingarten said.

Few studies have focused on the effects of merit pay. Teachers in Florida have complained about that state’s program, but University of Arkansas researchers who have studied the system in Little Rock, which also began its program with a privately funded pilot, say it has improved student achievement.

A New York City education historian, Diane Ravitch, warned that implementing an incentive program that teachers oppose could be counterproductive.

“The assumption behind merit pay is that teachers aren’t trying very hard to do a good job, and that the inducement of extra pay for results will get them to try harder. I am willing to bet that the overwhelming majority of teachers give their all every day, even without merit pay,” Ms. Ravitch said. “The Denver plan was formed with the advice and consent of the teachers; to impose a plan over the teachers’ objection makes it sound like a punitive act, not a reward.”

Mr. Klein said he has already implemented some forms of merit pay in the school system, including the Lead Teacher Program, which pays experienced teachers extra to train other teachers. Ms. Weingarten has said she doesn’t consider that a merit pay program. A compromise would be a school-wide merit pay system, which would given bonuses to the staff of an entire school for performance improvements — something both the union and Mr. Klein say they support.

Such a system has already been tried and discarded in New York City, the president of the Partnership for New York City, a coalition of business leaders, Kathryn Wylde, said. In the 1990s, her group funded a $15 million pilot program, Breakthrough for Learning, to experiment with merit pay systems,

“Unfortunately, the amount of money was too small when it came to school-wide. … We would argue that Breakthrough for Learning was a pilot program that didn’t work,” Ms. Wylde said. The business community still supports merit pay programs, she said, but added: “Based on our experience, we found that it’s not a problem that private money can solve.”

Merit pay experts say New York is ripe for another pilot program, however.

“There are a number of people that, privately at least, would be happy to run some demonstration programs,” a fellow at the Hoover Institution of Stanford University, Eric Hanushek, said. “Gates and Ford and others that have put some money into the New York City schools — if they put that in a targeted sort of way, you might make a real impact.”

A senior director at the Broad Foundation, which provided seed money for Denver’s program and which has subsidized other projects in New York City, Veronica Davey, suggested that her group would be open to helping fund merit pay if the chancellor was able to build support among different stakeholders, including teachers.

“I know the Broad Foundation would be ready to talk to the chancellor,” she said.