The New York City Department of Education released today a list of individual ratings of thousands of the city’s schoolteachers, a move that concludes a lengthy legal battle waged by the local teachers’ union and media, the Huffington Post reports. The Teacher Data Reports rate more than 12,000 teachers who taught fourth through eighth grade English or math between 2007 and 2010 based on value-added analysis. Value-added analysis calculates a teacher’s effectiveness in improving student performance on standardized tests — based on past test scores. The forecasted figure is compared to the student’s actual scores, and the difference is considered the “value added,” or subtracted, by the teachers. To some, the release means a step forward in using student data and improving transparency and accountability by giving parents access to information on teacher effectiveness…