It’s no secret that one of the main contributors to a country’s economic growth is the education and skill level of its workforce. While we have long recognized the importance of strong education, the debate over how we go about achieving superior educational results endures. One recent study has shed new light on an age-old question— what are the long-run impacts of teachers on student achievement and success?
Raj Chetty, the 2013 winner of the prestigious John Bates Clark Award (given every other year to an American economist under the age of 40 judged to have made the most significant contribution to economic knowledge), has focused much of his research effort on education. Using “big data” on 2.5 million school children over a 20-year period, Chetty and his colleagues addressed a key question in current education policy debates: How does a school teacher affect student success years later? With the benefit of this huge data set, which included students’ math and English test scores linked to the students’ corresponding teachers, records on college attendance rates, earnings, retirement savings, and a broad spectrum of other outcomes, Chetty was able to draw two key conclusions: First, by focusing on the change in student standardized test scores (i.e., “value added”), Chetty effectively captured the causal effect of teachers rather than the difference in the types of students teachers were assigned. Second, and most surprising, students who were assigned to high value-added teachers in elementary school showed noticeably lower teenage birth rates, significantly better college attendance, substantially higher salaries as adults, and higher levels of retirement savings, along with other measures of higher socio-economic status. Perhaps the most remarkable finding was that substituting a merely average teacher for a teacher in the bottom five percent of the value-added distribution would increase the present value of students’ lifetime earnings by more than $250,000 for the average classroom in the sample.
This result was quite unexpected, because prior education research had for the most part concluded that the impacts of teacher quality were not very long lasting, with test score gains fading over time and virtually disappearing in about three years. With a very limited ability to statistically examine long-run impacts, researchers were simply unable to argue convincingly that teachers made a big difference in the long-term success of their students.
While most parents know that the quality of the teacher is important for a child’s knowledge and grades in school, what Chetty and his colleagues discovered is that teacher quality has a substantial impact on long-run student success. Teachers clearly matter! Since our country’s future productivity and economic growth depends significantly on a highly-educated workforce and a population that exhibits responsible behaviors, it is critically important that we implement policies that get great teachers into the classroom and then provide assistance and encouragement to keep them there. It is also important to improve the knowledge and capability of the weakest teachers, or help them find employment in other, more suitable jobs.