BATON ROUGE - The state Board of Elementary and Secondary Education is expected to endorse at its Wednesday meeting using value added assessment for evaluating teachers on the basis of student performance.

Supporters told a committee Tuesday that data-driven evaluations will better grade teacher performance and enable schools to identify and reward highly performing teachers while giving targeted help to those who aren’t meeting standards.

The scoring standards will begin statewide with the 2012-13 school year. Public school teachers will have half their review pegged to student performance data - not the flat standardized test scores, but the growth in student achievement on those tests.

Teachers will be graded as highly effective, effective or ineffective.

The Legislature, at Gov. Bobby Jindal’s urging, approved the new evaluation procedure two years ago and a pilot program has been used in 20 districts since.

Teacher unions don’t like the change and a suit challenging them is likely.

Evaluations under the new method will be done annually, replacing the current system in which teachers got formal evaluations at least once every three years and not tied to student test scores. It will apply to teachers and administrators in traditional public schools and charter schools.