Who was the best teacher you ever had? What did you like about their class? Chances are each person reading this article can remember them with a fair amount of detail describing why they enjoyed the class. Good teachers have a tremendous, lasting impact on the students they instruct, which is why they are so valued and sought after by school leadership.
Raj Chetly and John Friedman of Harvard in collaboration with Jonah Rockoff at Columbia University set out to measure the impact of good teachers. Each of them is a professor of economics so logically, their study focused on the economic impact of these effective instructors. Identification of these successful teachers was through "value added ratings," measuring the impact of individual teachers have on the test scores of their students.
They compared students with similar demographic characteristics and backgrounds with the only variable being the teacher that taught them in school. They found that students that had a teacher rated as "excellent" for one year in fourth through eighth grade would have an increase in their lifetime income $4,600 compared to those that had not been instructed by a highly rated teacher. Students of these "excellent" teachers were .5 percent more likely to attend college. Their data surmised if they replaced a poor teacher with an average teacher, a single class' earning power would go up $266,000. Using these parameters, a good teacher that teaches for 30 years will have increased the earning power of all the students they have instructed by a collective $7.98 million.
Previous studies that measured the impact of teachers on their students' test scores found that the effect of a good teacher fades after three to four years.
This study indicates that taking a broader view of a teacher's impact illustrates long-term benefits. Professor Chetly acknowledged that using this "value added rating" exclusively to rate teachers is discouraged because of possible errors that could arise, but it should be used as a component of a broader rating system.
A bipartisan group of lawmakers in Washington state has just passed a teacher and principal evaluation system that will take effect in 2013. The main three components include: student evaluation will be included in measuring a teacher's effectiveness, teacher evaluation results will replace seniority as a criteria in determining teachers to be laid off or in other employment decisions and it will require schools to adhere to strict statewide standards which will prevent them from just interpreting the guidelines.
In New York City's quest to recruit effective teachers Mayor Bloomberg in his annual State of the City address stated the city would pay for $25,000 of student loans possessed by new teachers they hire that are in the top tier of their classes. Mayor Bloomberg stated "The marketplace keeps showing us that we have to be competitive if we are going to at least attract the best!"
Henry Brooks Adams once stated "A teacher affects eternity; he can never tell where his influence stops." Our school systems are full of many fine educators. The impact of ensuring every classroom is lead by a quality educator is priceless.
Editor's note: Steve Patchin is the director of the Center for Pre-College Outreach at Michigan Technological University.