Evaluating Teachers: The Important Role of Value-Added
Steve Glazerman, Susanna Loeb, Dan Goldhaber, Doug Staiger, Stephen Raudenbush, and Russ Whitehurst, Evaluating Teachers: The Important Role of Value-Added, (Washington, D.C.: The Brown Center on Education Policy at Brookings, November 2010).
This task-group paper from Brookings tackles four conventional arguments against the use of value-added calculations and show that each is misguided—and that none disproves the overall worth of such data. First, the authors address critics who decry value-added measures (because they fear public release of such data—think: L.A. Times). Glazerman et al. acknowledge that value-added measurement isn’t perfect, but assert that uncertainties surrounding this personnel policy shouldn’t dismiss the metric. Next, they take on naysayers who contend that value-added systems are imprecise and may harm teachers by labeling some good ones as bad (a false negative, statistically speaking). The authors admit this possibility, but argue two points. First, it is not about the teachers, but the students. And second, the relative infrequency of these false negatives compared to the current evaluation system which keeps ineffective teachers in classrooms at alarming rates would yield a much better outcome for students. Switching gears, the authors then explain that evaluation systems in other industries—such as college applications, investment firm comparisons, and baseball batting averages—all incorporate similar levels of imprecision but are well accepted as objective and fair nonetheless. They conclude that value-added teacher evaluations may not be perfect, and mustn’t be used uniquely, but are better predictors of teacher success than any other evaluation metric employed in schools today. Pretty persuasive, say we.