Georgia has formally requested a one-year delay as it moves to an evaluation system that ties teachers’ job-performance ratings to how their students perform academically.

That system was supposed to be fully implemented this school year using student performance on the state’s standardized test. Teachers were to get one of four designations — exemplary, proficient, needs development or ineffective — based largely on how much their students’ academic performance improved. Principals would also be evaluated based in part on student performance.

Those repeatedly designated as needing development or ineffective could eventually lose their certification.

Twenty-six districts in the state are using money from the federal Race to the Top education grant to give bonuses to their top-rated teachers. Those bonuses will still be given.

Georgia promised to come up with its own system for evaluating teachers when it was granted a waiver from the No Child Left Behind federal education law.

But with the state moving to a new standardized test this school year, Georgia Superintendent John Barge has asked the U.S. Department of Education for permission to delay implementation of its evaluation system.

“As we transition to a new assessment system, we need additional time before incorporating student growth in high-stakes personnel decisions,” Barge said. “A one-year delay will ensure that teachers and leaders are aware of the impact of more rigorous standards and high-quality assessments, and that they have time to amend instructional practices and engage in the necessary professional learning.”

U.S. Education Secretary Arne Duncan has invited states to seek a delay. His department acknowledged receipt of Georgia’s request, but it has not officially said whether it will be granted.

If the request is granted, Georgia will collect the data used in the new evaluation system but personnel decisions won’t be tied to that data this year.

Some educators have expressed concern about the new evaluation system, arguing that student performance is affected by a variety of factors that go beyond the classroom.

Tim Callahan, spokesman for the Professional Association of Georgia Educators, praised the move to seek a delay in full implementation of the evaluation system.

“We know there needs to be a robust and credible way to evaluate staff, but with something that is both high-stakes and complex, it’s more important to do it right rather than do it fast,” Callahan said. “We remain concerned that there is little or no research base to support the underlying suppositions of tying 50 percent of a teacher’s evaluation to student test scores, and in fact the experts in the field argue against such practices.”