by Mark Ehlert, Cory Koedel, Eric Parsons, Michael Podgursky
February 07, 2014
State education agencies and school districts increasingly use measures based on student test-score growth in their systems for evaluating school and teacher performance. These systems inform high-stakes decisions such as which schools to close and which teachers to retain. Performance metrics tied directly to student test-score growth are appealing because although schools and teachers differ dramatically in their effects on student achievement, researchers have had great difficulty linking these performance differences to characteristics that are easily observed and measured. Yet, the question of how best to measure student test-score growth for the purpose of school and teacher evaluation remains debated. This study examines three competing approaches to measuring growth in student achievement. We prefer the third approach, which ensures that the comparisons used to measure performances are between similarly circumstanced schools and teachers.