A court decision this week involving Los Angeles Unified has raised again the contentious issue of evaluating teachers using standardized test scores. But a recent report for the think tank Education Sector recommends adopting the same method developed by Los Angeles Unified to replace the Academic Performance Index as a statewide way of measuring schools’ progress.
Called Academic Growth over Time, AGT is a value-added model that compares students’ actual performance on state tests to their predicted performance based on demographic characteristics – family income, language, and ethnicity – as well as past test scores. The intent is to distinguish factors of learning that schools can control from those they can’t.
The use of AGT to evaluate individual teachers has sharply divided teachers in Los Angeles Unified. United Teachers Los Angeles opposes using AGT in any manner, while teachers affiliated with Teach Plus Los Angeles and Students Matter support using it as one of several measures, counting for no more than a third of an evaluation. But less controversial is the district’s use of AGT as a tool to evaluate schools, in part because it involves a larger number of student test scores and doesn’t call for high-stakes decisions affecting individual teachers’ careers. To the contrary, a schoolwide AGT can encourage collaboration and team-teaching