In a move that could cement New York City’s reputation as an incubator for methods of making public education behave more like the private sector, the city will hand out almost $20 million in performance bonuses to educators this fall.

Teachers and principals are traditionally paid according to years of experience and numbers of degrees, but innovators in the education field have argued that pay should instead be based on how well they perform in the classroom.

The new bonuses, for both teachers and principals in schools where students’ test scores improved, follow that line of thought. Teachers receive as much as $3,000 apiece if their entire school’s students hit a battery of “performance targets” mainly determined by state test scores; principals will get as much as $25,000 for getting high scores on their progress reports.

“In every good company, excellence is rewarded,” Mayor Bloomberg said in a statement yesterday.

The bulk of the bonuses, $14 million in total, are going to members of the teachers union — teachers as well as guidance counselors and school secretaries — and are being paid for by private donations collected last year.

The president of the teachers union, Randi Weingarten, negotiated the performance-pay project with Mr. Bloomberg and Chancellor Joel Klein last year.

While many people, including Mr. Klein, have pushed for giving bonuses according to each individual teacher’s performance, the teachers and their unions have resisted such arrangements, saying they lead to unhealthy infighting and are unfair to those who teach untested subjects such as art and gym.

The final deal struck a compromise between the two positions: Bonuses are given to a school in a bulk sum if its students hit certain targets for test scores and attendance rates, but teachers at the school can decide how they want to divvy it up among themselves once they get it.

Even that deal upset some teachers; 14% of schools eligible for the bonus program voted not to participate.

Of the roughly 250 schools that did participate, 89 hit the targets.

The schools were chosen because they serve disadvantaged students.

Schools set up internal committees to decide how to divide up their bonuses, which worked out to between $1,500 and $3,000 a teacher.

Announcing the program last year, Mr. Klein said he hoped teachers would choose to reward the largest bonuses to those teachers whose students showed the greatest test score gains.

A preliminary look at how schools divided the funds up, provided by school officials, suggests that did not happen at many schools.

About half of the schools, 43, distributed the money evenly among all staff represented by the teachers union; the remaining 46 gave each teacher a slightly different amount, depending on factors such as job title, according to school officials.

A smaller set of funds, $5.5 million, went to principals and assistant principals whose schools scored the highest raw point total on their progress reports.

The top 1% of principals — 12 people — are getting $25,000 bonuses. The bonuses scale down in size according to each principal’s rank in score, ending with those who scored between the top 11% and the top 20%, who get $7,000.