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Should student test scores be used to evaluate teachers?
Debate rages over using the 'value-added' model in measuring teacher effectiveness
The so-called value-added model is an “imperfect, but still informative” measure of teacher effectiveness, especially when it is combined with other measures, according to the preliminary results of a large-scale study funded by the Bill and Melinda Gates Foundation. The study’s early findings have ratcheted up the debate over whether student test scores should be used in evaluating teachers—and if so, how.
The report, entitled “Learning About Teaching: Initial Findings from the Measures of Effective Teaching Project,” reportedly gives the strongest evidence to date of the validity of the value-added model as a tool to measure teacher effectiveness.
The $45-million Measures of Effective Teaching (MET) Project began in the fall of 2009 with the goal of building “fair and reliable systems for teacher observation and feedback.”
Teacher quality is important, but “teacher evaluation is a perfunctory exercise,” the report said. Principals tend to go through the “motions” of evaluation, and “all teachers receive the same ‘satisfactory’ rating.” The study aims to fix this “neglect” and help devise a system that gives teachers the feedback they need to grow, the report said.
What is the value-added model?
Value-added is a controversial statistical method that relies on test-score data to determine a teacher’s effectiveness. Each student’s performance on past standardized tests is used to predict how he or she will perform in the future. Any difference between the student’s projected result and how the student actually scores is the estimated “value” that the teacher has added or subtracted during the year.
The value-added model is thought to bring objectivity to teacher evaluations, because it compares students to themselves over time and largely controls for influences outside teachers’ control, such as poverty and parental involvement.
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Value-added has been a buzz word among educators since the Obama administration’s “Race to the Top” grant program began promising money to school systems that adopt to certain requirements, such as evaluating teachers’ performance by using factors like student achievement.
Critics of the value-added model fear school leaders might make serious decisions about individual teachers based on these projections alone.
“This is a problem with value-added,” said Raegen T. Miller, associate director for education research at the Center for American Progress. “So far, value-added has been on its own. People are very scared that administrators would start making serious decisions about individual teachers just based on that information—and nobody thinks that should be done. It doesn’t take away people’s fear of it. We can write all we want that we should use multiple measures; now, we actually [should] start having multiple measures.”
That’s the good news that comes from the preliminary findings of the MET Project. Based on these findings, researchers recommend that school leaders use multiple measures, in addition to value-added, to evaluate teachers effectiveness.