Myths and Facts about Value-Added Analysis
November 08, 2011
Nearly everyone agrees on the need to create better teacher evaluation systems that reflect how well teachers are helping students learn. How to actually measure student learning can be a thornier issue.
One of the best methods currently available is called value-added analysis. Value-added uses standardized test scores to determine how much a teacher helped her students learn over the course of the year.
If you’ve heard about value-added, you probably haven’t heard many good things. Concern about value-added has caused some policymakers to back away from supporting its use in teacher evaluations.
But here's why value-added should have a place at the table:
- It’s a reliable indicator of performance—about as reliable as batting averages in baseball, for example.
- It’s the product of nearly three decades of research by leading academics and economists, and has been used by states and school districts since the 1990s.
- It predicts future student success. Teachers with high value-added scores are also likely to help their future students master important skills—as measured by both traditional tests and more comprehensive assessments.
- It controls for a student’s past academic performance and demographic factors. That means teachers get the credit they deserve for helping all their students improve—even those who start the year far behind grade level—and aren’t penalized for the effects of poverty or other factors beyond their control.
Value-added isn’t perfect—no single measure is—and nobody’s saying it should be the only way schools evaluate teachers. But the balance of evidence supports its use. Alongside classroom observations and other measures, it has an important role to play in giving teachers and schools a more accurate and objective picture of what’s happening in the classroom