N.Y.C. Schools Collecting Pupil Test Data on Teachers

New York City is collecting data to measure the performance of 2,500 teachers based on how well their students perform on tests, but the experiment is under fire from the local teachers’ union.

Under the pilot project at 120 of the city’s 1,400 schools, teachers are being measured on the number of students making predicted progress, and how their performance compares with that of peers who have similar students and similar experience, as well as with teachers citywide. The value-added model controls for such characteristics as class size, number of special education students and English-language learners, and classroom-discipline issues.

Officials in the 1.1 million-student district say they are not sure exactly how they will use the data that they collect, and whether the information will be used to evaluate teachers or...