National Teaching Expert Calls "Value Added" Performance Metric Unreliable

Linda Darling-Hammond (Photo courtesy of Stanford Center for Opportunity Policy in Education)
Linda Darling-Hammond (Photo courtesy of Stanford Center for Opportunity Policy in Education)
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Darling-Hammond pointed to numerous areas where she says the U.S. lags behind the top performing nations in education - from its graduation rate, scholastic achievement and college readiness, to federal support and equal access to high quality schools. She said the U.S. has to choose its reforms wisely. One she warned against involves teacher evaluation.

The "value-added" model requires teachers to show progress based on test scores each year. Darling-Hammond says it's been shown to unfairly punish already high-performing teachers.

"I'm a research who was very interested and enthusiastic about value added a few years ago, who has, among many other researchers, found that it has a lot more difficulty and problems than we realized," Darling Hammond said. "So the National Research Council has recently come out to say value added should not be used, because it's very unstable. It's unreliable. It turns out that it's biased."

Ohio began using value-added reports in select districts in 2011, and is slated to include them in all schools beginning next year. It's part of the effort to move away from seniority and education credentials as the primary factors in teacher retention decisions. Value-added reports will account for 50 percent of a teacher's evaluation.

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