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The L.A. Times reported today that Los Angeles school district leaders are “poised to plunge ahead with their own confidential 'value-added' ratings this spring, saying the approach is far more objective and accurate than any other evaluation tool available, despite its complexity.” Incoming Superintendent Deasy said “We are not questing for perfect. We are questing for much better.”
Supporters of Value-Added systems for evaluating teachers agree that there are unresolved issues with how to tweak the mathematical models to provide the most accurate measures of teacher performance. However, because Value-Added models are based on student test scores, no amount of tweaking can make them a meaningful measure of teacher performance.
The first problem is that there is no universal agreement on which formula can most accurately isolate a teacher's influence from other factors that affect student learning — and different formulas produce different results.. The Times referenced a 2010 study by researchers at Stanford University and UC Berkeley who found that teachers with more African American and Latino students received lower value-added scores than those with more Asian students.
However, it is possible that no formula will be able to accurately tease out the teacher’s influence from influences like home life and socioeconomic background. Student test scores can only tell us how students are doing. They cannot tell us why. Students who are disengaged from school, come to class ill-prepared, have short attention spans and give up easily are less likely to make significant gains on exams, regardless of the quality of their teachers.
A more significant issue is that the entire push for Value-Added evaluations is predicated on the continued abuse of high stakes standardized exams and the bogus premise that they are a useful measure of student learning. Yet the obsession with standardized tests has been a disaster for public education and it is a terrible way to measure learning or teaching. Our goal should not be to graduate people who excel at multiple choice tests. Rather, it should be to graduate people who can solve problems, think critically, and work well with other people. Good teaching should not be measured by how well you can make kids sit still and bubble in answers.
By accepting Value-Added schemes, we are necessarily accepting a continuation of high stakes exams and the concomitant loss of instructional time, creative teaching, inquiry-based learning and critical thinking and, worst of all, a stifling of student curiosity and enthusiasm for learning. When teachers’ evaluations, pay and promotions become tied to how much their students improve on standardized tests, they will be even more inclined to teach to the test. Indeed, with their careers on the line, teachers may entirely give up on creative, engaging and thought-provoking lessons in exchange for rote memorization drills and practice ruling out the “obvious wrong answer.”