Tuesday, August 31, 2010

Report on eval teachers by test scores

I'll give you three guess what a panel of experts that includes Diane Ravitch, Linda Darling-Hammond and Richard Rothstein, on behalf of a union-backed organization (Economic Policy Institute), concluded about whether it's fair to use student test scores to evaluate teachers…  Here's a summary:

Student test scores are not reliable indicators of teacher effectiveness, even with the addition of value-added modeling (VAM), a new Economic Policy Institute report by leading testing experts finds. Though VAM methods have allowed for more sophisticated comparisons of teachers than were possible in the past, they are still inaccurate, so test scores should not dominate the information used by school officials in making high-stakes decisions about the evaluation, discipline and compensation of teachers.

…The co-authors make clear that the accuracy and reliability of analyses of student test scores, even in their most sophisticated form, is highly problematic for high stakes decisions regarding teachers . Consequently, policymakers and all stakeholders in education should rethink this new emphasis on the centrality of test scores for holding teachers accountable.

Analyses of VAM results show that they are often unstable across time, classes and tests; thus, test scores, even with the addition of VAM, are not accurate indicators of teacher effectiveness.    Student test scores, even with VAM, cannot fully account for the wide range of factors that influence student learning, particularly the backgrounds of students, school supports and the effects of summer learning loss.  As a result, teachers who teach students with the greatest educational needs appear to be less effective than they are.  Furthermore, VAM does not take into account nonrandom sorting of teachers to students across schools and students to teachers within schools.

There are further negative consequences of using test scores to evaluate teacher performance.  Teachers who are rewarded on the basis of their students' test scores have an incentive to "teach to the test," which narrows the curriculum not just between subject areas, but also within subject areas.  Furthermore, creating a system in which teachers are, in effect, competing with each other can reduce the incentive to collaborate within schools-and studies have shown that better schools are marked by teaching staffs that work together.  Finally, judging teachers based on test scores that do not genuinely assess students' progress can demoralize teachers, encouraging them to leave the teaching field.

Like all misleading "research", there's some truth here.  NOBODY thinks student test scores and value-added analyses should be used in isolation, but they absolutely MUST be part of a completely revamped teacher evaluation system.


In new EPI report, leading educational testing experts caution against heavy reliance on the use of test scores in teacher evaluation

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