Volume 25, Number 2
March/April 2009

An Inexact Science

What are the technical challenges involved in using value-added measures?

by Robert Rothman

 

Every year, teachers in Tennessee receive two reports on their students’ academic performance. The first, which details their scores on state accountability tests, is reported publicly and used in school reports on student achievement.

The second report is shared only with the teacher and the principal. That report analyzes the students’ test results based on their past performance and background characteristics to calculate the “value added” by the teacher in terms of student learning. Teachers with high value-added scores improved student performance faster than expected, while those with low scores did less well.

Under state law, the value-added scores may not be used to grant or deny tenure, pay increases, or other rewards. However, principals have used the information to make decisions about professional development, and some districts have used the scores in special initiatives. Chattanooga, for example, offered incentives to teachers with high value-added scores who agreed to teach in low-performing schools.