Complete Coverage

'Value-Added' Formulas Strain Collaboration

The rapidly changing debate on how to account for student achievement in teacher evaluations is putting teacher-district relationships to the test across the country.

More than half the states now require districts to take student achievement into account when evaluating a teacher's performance. In most cases, that's calculated through a so-called value-added model that attempts to account for a teacher's role in a student's growth over the course of a year, via test scores and other performance measures. Most of the push for value-added evaluation systems has come only in the past few years, driven in part by the federal Race to the Top grants , which gave extra weight to states that included achievement-based teacher evaluations in their applications, and by the federal Teacher Incentive Fund grants , which so far have supported experiments in 175 districts in 33 states using student achievement in teacher performance-pay plans.

"Some of the fear and worries we're seeing now, not just from unions but across the board, are because we've seen an enormous amount of change and uncertainty in a short amount of time," said Christopher A. Thorn, the associate director of the University of Wisconsin's Value-Added Research Center and its director for data quality and systems innovation. Moreover, he said, "Budget pressures have actually stressed districts and pushed people to do these things. Forget about paying teachers. That's a minor part of the reforms we see in districts; they're changing who they hire, they're changing their leadership systems, they're changing professional development. They are changing...