EduFocus # 9: How much value does an effective teacher add?

One of the primary roles of schools and teachers is to add value to students. That is, teachers and schools are expected to make their students “more” than when they first entered the classroom. However that “more” is defined, it measures the value the teacher or school has added and how they have improved  the student.There is no universally accepted characterization of what value added (VA) means and what it should measure, but there is wide acceptance of the idea that schools and teachers should make students better at something.A recent study conducted by professors at Harvard and Columbia in the U.S. has suggested that effective teachers do not only make a difference in student performance on tests, but also in students’ lifelong earnings.Using students’ test scores as the measure of VA, the researchers found  that “teachers’  impact  on students are substantial” (Chetty, Friedman, & Rockoff, 2011).  The study found that students assigned to higher VA teachers showed positive results well beyond their own classroom. Students who benefited from great teachers – that is, those with improved test scores according to this study - were “more likely to attend college, earn higher salaries, live in better neighborhoods, and save more for retirement.”  It even found that those children were also less likely to have children as teenagers. Overall, the researchers claim that effective teachers can raise lifetime earnings of a class by over US$250,000.00.This study has drawn strong response - both negative and positive – from education policy makers and U.S. President Barack Obama, who quoted the findings in his State of the Union Address on January 24, 2012. .In one case, the researchers themselves added a word of caution about the interpretation and use of the study to guide policy-making in education, especially in the evaluation of teachers:“Overall, our study shows that great teachers create great value and that test score impacts are helpful in identifying such teachers.  However, more work is needed to determine the best way to use VA for policy.  For example, using VA in teacher evaluations could induce counterproductive responses that make VA a poorer measure of teacher quality, such as teaching to the test or cheating.”Read full study here.