Evaluating teachers based partly on student test scores is unreliable, concludes a study in Educational Evaluation and Policy Analysis. Researchers analyzed a subsample of 327 fourth- and eighth-grade mathematics and English-language-arts teachers across six school districts.
“Some teachers who were well-regarded based on student surveys, classroom observances by principals and other indicators of quality had students who scored poorly on tests,” reports the Washington Post. Some poorly regarded teachers had students who did well.
Thirty-five states and the District of Columbia require student achievement to be a “significant” or the “most significant” factor in teacher evaluations. Just 10 states do not require student test scores to be used in teacher evaluations.
Most states are using “value-added models” — or VAMs — which are statistical algorithms designed to figure out how much teachers contribute to their students’ learning, holding constant factors such as demographics.
Last month, the American Statistical Association warned against used VAMS, saying that “recent studies have found that teachers account for a maximum of about 14 percent of a student’s test score.”
“We need to slow down or ease off completely for the stakes for teachers, at least in the first few years, so we can get a sense of what do these things measure, what does it mean,” said Morgan S. Polikoff, a USC assistant professor of education and co-author of the study. “We’re moving these systems forward way ahead of the science in terms of the quality of the measures.”