Growth Data for Teachers Under Review

As states’ information-collection systems grow more sophisticated, officials are grappling with where to draw the line on how “value added” data on teachers can be used.

Tennessee law permits the use of such data for teacher evaluation as long as the data meet certain technical requirements. The state’s Hamilton County district, with union approval, also offers bonuses based on the data.

California serves as a counterpoint: A 2006 state law establishing a new teacher-identification database prevents such data from being used for teacher pay, evaluation, or personnel decisions. Some stakeholders there say it might not even be permissible to link teacher...