What have value-added studies shown about the impact a single teacher can have on student performance?
By implementing a value-added approach, states can ensure that their students receive the quality teaching they need to increase their odds for success. William Sanders’ research in Tennessee indicates that fifth grade students who had three very effective teachers in a row gained 50 percentile points more on the state’s assessment than students who had three ineffective teachers. A similar study in Dallas, using a different test and a different value-added methodology, found identical results. Additional research conducted by Dr. June Rivers, associate director of EVAAS® distributors of the Sanders’ value-added model, the indicates that the chances for fourth-graders in the bottom quartile of performance to pass the state’s high-stakes exit exam in ninth grade were less than 15 percent if their fifth, sixth, seventh and eighth grade teachers were drawn from the bottom 25 percent of the teacher pool (as measured by value-added), but a 60 percent chance of passing if they had four teach
