Why naming names is wrong
Blog by Diane Ravitch/Education Week
Dear Deborah, A year ago, the Los Angeles Times created a media sensation when it obtained the names and test scores of thousands of teachers, then commissioned a researcher to rate them in relation to their "effectiveness" in raising test scores. The Times then published online the names and ratings of those thousands of teachers. U.S. Secretary of Education Arne Duncan saluted the Times for rating teachers and naming names, but the overwhelming majority of testing and evaluation experts thought it was a terrible idea. The experts understand that evaluating teachers by their students' test scores is fraught with problems. The ratings are inaccurate (there is a large margin of error) and unstable (a teacher who is effective one year may be ineffective the next year, depending on the composition of his or her classes since students are not randomly assigned). They are plagued with missing data, they ignore the effects of non-school factors. Nor do they acknowledge that students are influenced by multiple teachers, not just one. Critics point out that teachers should be judged by multiple measures, not just by test scores. (more...)