Because of teachers' complaints, Pittsburgh school officials are considering changes to a controversial policy that set 50 percent as the minimum grade a student can receive on any test or assignment.

The willingness to fine-tune the policy stems partly from teachers' reports that some students have refused to do or re-do work, preferring to settle for the 50 percent minimum, Pittsburgh Public Schools spokeswoman Ebony Pugh and Pittsburgh Federation of Teachers President John Tarka said yesterday.

Mr. Tarka said such defiance cannot be tolerated, and Linda Lane, deputy superintendent for instruction, assessment and accountability, said students must be held accountable for their work.

Teachers also have complained that a 50 percent minimum has the effect of more equally weighting tests, homework, class participation, projects and other vehicles for grading students. Teachers are demanding some differentiation, Mr. Tarka said.

Dr. Lane said the policy would be adjusted, not abandoned. She said a committee of teachers and administrators is working on changes but didn't know when modifications would be implemented.

In September, the district and union sparked a firestorm with a joint memo outlining the policy and instructing teachers to comply with it. Officials said they were merely standardizing a policy that had been in place in some city schools for years.

The policy also is used in other districts.

Officials said the policy gives students a chance to recover from a bad test or marking period, warning that students who lose hope have little incentive to stay in school. But teachers -- especially those in high schools -- said the policy coddles lazy students, amounts to grade inflation and undercuts Superintendent Mark Roosevelt's "Excellence for All" campaign.

The policy didn't go over well outside the district, either. It was skewered by bloggers as far away as Australia.

During the first marking period, teachers complied with the policy "to a great extent," Mr. Tarka said, adding, "It was done grudgingly in many cases."

The district is well into the second marking period now, and teachers complained about the policy as recently as Tuesday during a meeting with Mr. Roosevelt and Dr. Lane.

Like Dr. Lane, Mr. Tarka said he continues to support a policy that gives students a chance to recover.

"We want our grading system to be rigorous and also equitable," he said. "We don't want to give anything away. At the same time, we don't want to trap a kid, either."