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Michelle A. Rhee, center, the Washington schools chancellor, fired about 25 teachers partly over poor value-added evaluations.
By SAM DILLON
Irfan Khan/Los Angeles Times
Karen Caruso teaches in Los Angeles, where some teacher ratings are made public.
A growing number of school districts have adopted a system called value-added modeling to answer that question, provoking battles from Washington to Los Angeles — with some saying it is an effective method for increasing teacher accountability, and others arguing that it can give an inaccurate picture of teachers’ work.
The system calculates the value teachers add to their students’ achievement, based on changes in test scores from year to year and how the students perform compared with others in their grade.
People who analyze the data, making a few statistical assumptions, can produce a list ranking teachers from best to worst.
Use of value-added modeling is exploding nationwide. Hundreds of school systems, including those in Chicago, New York and Washington, are already using it to measure the performance of schools or teachers. Many more are expected to join them, partly because the Obama administration has prodded states and districts to develop more effective teacher-evaluation systems than traditional classroom observation by administrators.
Though the value-added method is often used to help educators improve their classroom teaching, it has also been a factor in deciding who receives bonuses, how much they are and even who gets fired.
Michelle A. Rhee, the schools chancellor in Washington, fired about 25 teachers this summer after they rated poorly in evaluations based in part on a value-added analysis of scores.
And 6,000 elementary school teachers in Los Angeles have found themselves under scrutiny this summer after The Los Angeles Times published a series of articles about their performance, including a searchable database on its Web site that rates them from least effective to most effective. The teachers’ union has protested, urging a boycott of the paper.
Education Secretary Arne Duncan weighed in to support the newspaper’s work, calling it an exercise in healthy transparency. In a speech last week, though, he qualified that support, noting that he had never released to news media similar information on teachers when he was the Chicago schools superintendent.
“There are real issues and competing priorities and values that we must work through together — balancing transparency, privacy, fairness and respect for teachers,” Mr. Duncan said. On The Los Angeles Times’s publication of the teacher data, he added, “I don’t advocate that approach for other districts.”
A report released this month by several education researchers warned that the value-added methodology can be unreliable.
“If these teachers were measured in a different year, or a different model were used, the rankings might bounce around quite a bit,” said Edward Haertel, a Stanford professor who was a co-author of the report. “People are going to treat these scores as if they were reflections on the effectiveness of the teachers without any appreciation of how unstable they are.”
Other experts disagree.
William L. Sanders, a senior research manager for a North Carolina company, SAS, that does value-added estimates for districts in North Carolina, Tennessee and other states, said that “if you use rigorous, robust methods and surround them with safeguards, you can reliably distinguish highly effective teachers from average teachers and from ineffective teachers.”
Dr. Sanders helped develop value-added methods to evaluate teachers in Tennessee in the 1990s. Their use spread after the 2002 No Child Left Behind law required states to test in third to eighth grades every year, giving school districts mountains of test data that are the raw material for value-added analysis.
In value-added modeling, researchers use students’ scores on state tests administered at the end of third grade, for instance, to predict how they are likely to score on state tests at the end of fourth grade.
A student whose third-grade scores were higher than 60 percent of peers statewide is predicted to score higher than 60 percent of fourth graders a year later.
If, when actually taking the state tests at the end of fourth grade, the student scores higher than 70 percent of fourth graders, the leap in achievement represents the value the fourth-grade teacher added.
Seource: http://www.nytimes.com/2010/09/01/education/01teacher.html?_r=1&ref=education
