Grading Teachers in Los Angeles Value-added measurement shows that many of the city's teachers don't belong in the classroom.

Marcus Winters

It's the start of another school year, and parents everywhere are asking themselves: Is my child's teacher any good? The Los Angeles Times recently attempted to answer that question for parents. Using a statistical technique known as "value added"--which estimates the contribution that a teacher made to a student's test-score gains from the beginning to the end of the school year--the paper analyzed the influence of third-, fourth-, and fifth-grade teachers on the math and reading scores of students in the Los Angeles Unified School District. The results suggest a wide variation in the quality of L.A.'s teachers. The paper promises a series of stories on this issue over the next several months.

The Times has admirably highlighted the importance of using data to evaluate teacher performance, confirming the findings of a wide and growing body of research. Studies show that the difference between a student's being assigned to a good or bad teacher can mean as much as a grade level's worth of learning over the course of a school year. While parents probably don't need studies to tell them who the best teachers are--such information is an open secret in most public schools--academic research helps underscore the inadequacy of the methods currently used to evaluate teacher performance. Even the nation's lowest-performing school districts routinely rate more than 95 percent of their teachers as satisfactory or higher.

Posted by Jim Zellmer at August 27, 2010 5:14 AM
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