This from The Nation:
The New York Times and WNYC are preparing to publish online the “value-added” ratings of 12,000 New York City teachers—an estimation of each teacher’s impact on his or her students’ standardized test scores in math or English.
Value-added, a tool developed by economists, is highly controversial, and the Times and WNYC acknowledge the measure is volatile. (To read about how value-added scores are calculated in New York, click here.) For math teachers, the margin of error in estimating a teacher’s impact on students’ test scores could be up to thirty-five points on a 100-point test; for English teachers, the margin of error could be up to fifty-three points. A state court ruled against the United Federation of Teachers’ attempt to prevent the city from releasing the data to news agencies.
In 2010, the Los Angeles Times created an online database of value-added scores, searchable by teacher name. Ever since, the question of whether to publicly release such reports has split the standards-and-accountability school reform movement. New York Mayor Mike Bloomberg and federal Secretary of Education Arne Duncan support publication with names attached. But yesterday, Bill Gates wrote a Times op-ed arguing that although value-added is a useful tool when combined with more holistic evaluation methods, such as classroom observation, he opposes releasing individual teachers’ value-added scores to the public, calling publication a “shaming” device. Teach for America founder Wendy Kopp is also on the record opposing publication...