Anne Arundel County school officials are eyeing expansion of an ambitious -- and expensive -- incentive program aimed at getting teachers and principals to work at schools that have failed to meet state performance targets and offering added bonuses if those schools improve.

The program, which school officials say might cost up to $3 million this year at a total of 14 failing schools, has drawn interest from staffers at schools that successfully meet the state's performance targets, as well as from teachers' assistants, who are not currently eligible for the bonuses.

The county school board recently approved a legislative agenda that says it supports -- in principle -- stipends for teachers and other employees who work with students in all schools that make yearly progress as defined by the state.

Bonus programs long have been offered around the country by districts looking to find and retain talented staff. And the federal No Child Left Behind Act lets high-poverty school systems offer incentive pay programs based on teacher and principal qualifications, among other criteria.

But Anne Arundel is going further than other Baltimore area school systems, offering bonuses not only to keep qualified teachers and principals at troubled schools but rewarding them additionally if the schools show improvement.

Talk of the program's expansion comes as Anne Arundel and other school districts around Maryland are squeezed by initiatives such as the state's requirement for all-day kindergarten.

So far, Anne Arundel has not formally moved to widen the program or provide funding for such an expansion.

Still, Anne Arundel school staffers are eager to see some broadening of the incentive program, which currently offers bonuses of $1,500 to teachers and $5,000 to principals at schools that failed to make the grade on statewide tests in consecutive years -- and double those amounts if their students meet state targets this year.

Already, the incentive program turned out to be more costly than expected. Originally, eight schools were eligible to receive the funds, at a maximum cost of $1.2 million.

The price tag increased because six additional schools were classified this fall as missing the mark.

In a recent interview, however, Anne Arundel Schools Superintendent Eric J. Smith said he is prepared to cover the costs and added that he would be pleased to have to solve the happy dilemma of paying stipends to all the schools meeting the state's performance objectives.

But expansion of programs such as Anne Arundel's must be done carefully, said Dan Goldhaber, a research associate professor at the Evans School of Public Policy at the University of Washington. "A couple years down the line, it ends up being very costly," he said.

Goldhaber recommends that proper planning be in place to ensure that the incentives can be paid fully. "Otherwise, it poisons the notion of the incentive going forward," he said.

Some of those now excluded from Anne Arundel's program say it should be expanded to make the incentive system more consistent.

Susan V. Bachmann, now in her second year as principal at Harman Elementary School in Hanover, said her school achieved its performance targets last year, despite the challenges of having a high-poverty population.

"Unfortunately, we did so wonderful that we didn't get to have the bonus," she said.

Bachmann supports expansion and fine-tuning of the program, saying, "Businesses and different companies get bonuses and things like that when they accomplish goals."

Others point out that once a school achieves progress, teachers and principals there are no longer eligible for the retention bonus -- perhaps a disincentive to achieve.

Teacher assistants argue that they should be included in the program because their job duties have evolved over the past two decades and now primarily support instruction of students directly.

Some took their case directly to the school board at a recent meeting.

"Teacher assistants seem to have fallen by the wayside or have been taken for granted," said Sheri Fonte, who leads a reading resource program at Lindale Middle School, where teachers received bonuses last year.

In a later interview, Fonte said, "You can't reward half the team and not the rest of the team."

The county schools chief agrees. "I think teacher assistants are playing an ever-increasing role in education in America," Smith said in an interview. "I think that they certainly should be included in any discussion around pay for performance."

But some critics warn that even an expanded incentive program might not reward all of those who deserve it.

"I believe everyone needs to be adequately compensated," said Sheila Finlayson, president of Anne Arundel's teachers union. "Now, you're saying the only way you can get additional compensation is if you work in challenged schools."