VALUE ADDED AND STUDENT OUTCOMES
Latest US report claims clear evidence that good teachers really do make a big long term difference
More research from the States on the controversial “value-added ratings,” which purport to measure the impact individual teachers have on student test scores. A teacher’s “value-added” is defined as the average test-score gain for his or her students, adjusted for differences across classrooms in student characteristics. Consensus though on this issue and how you measure added value and ensure accuracy and fairness is hard to find. Few doubt though the importance of effective teachers and the positive effect they have on pupil performance and attainment. It is equally true that evidence shows that poor teachers have a negative impact on outcomes.
This latest paper ‘The Long Term Impacts of Teachers :Teacher Value Added and Student Outcomes in Adulthood’ is likely to influence the on-going national debates about the importance of quality teachers and how best to measure that quality. The quality of teachers and teachers effectiveness and their impact on pupil performance are the big issues driving the reform agenda in the USA. The paper, by Raj Chetty and John N. Friedman of Harvard and Jonah E. Rockoff of Columbia, all economists, examines a larger number of students over a longer period of time with more in-depth data than many earlier studies, allowing it is claimed for a deeper look at how much the quality of individual teachers matters over the long term. Many school districts, including those in Washington and Houston, have begun to use value-added metrics to influence decisions on hiring, pay and even firing. Supporters argue that such metrics hold teachers directly accountable and can help improve the educational outcomes of millions of children. Detractors, most notably a number of teachers unions, say that isolating the effect of a given teacher is harder than it seems, and might unfairly penalize many teachers as there are clearly other variables that impact on pupils performance. Critics particularly point to the high margin of error with many value-added ratings, noting that they tend to bounce around for a given teacher from year to year and class to class. But looking at an individual’s value-added score for three or four classes, the researchers in this new study claim to have found that some consistently outperformed their peers. “Everybody believes that teacher quality is very, very important,” says Eric A. Hanushek, a senior fellow at the Hoover Institution at Stanford and longtime researcher of education policy. “What this paper and other work has shown is that it’s probably more important than people think. That the variations or differences between really good and really bad teachers have lifelong impacts on children.” The study found, inter alia, that ‘When a high value-added (top 5%) teacher enters a school, end-of-school-year test scores in the grade he or she teaches rise immediately… and students assigned to such high value-added teachers are more likely to go to college, earn higher incomes, and are less likely to be teenage mothers. On average, having such a teacher for one year raises a child’s total lifetime income by $9,000. And the gains from replacing a low value-added (bottom 5%) teacher with one of average quality grow as more data are used to estimate value-added. The gains are $190,000 with 3 years of data and eventually surpass $250,000.
THE LONG-TERM IMPACTS OF TEACHERS: TEACHER VALUE-ADDED AND STUDENT OUTCOMES IN ADULTHOOD
Raj Chetty, Harvard University and NBER; John N. Friedman, Harvard University and NBER Jonah E. Rockoff, Columbia University and NBER
Note-Given the clear international evidence on the impact that good and bad teachers have on student outcomes, the Governments drive to focus on the quality of teachers and their moves to make it easier to remove incompetent teachers from the profession look to be necessary, minimum steps to improve pupil outcomes.