An eye-catching recent statistical analysis by economists at Harvard and Columbia universities finds that having a high-quality teacher for even one year can have a measurable long-term impact on students’ career outcomes.
The study tracked one million children from a large urban school district from 4th grade to adulthood. The researchers gauged the effectiveness of the students’ teachers in grades 4 to 8 through value-added analyses, calculating their impact on standardized test scores over time, with adjustments made for differences in student characteristics.
The researchers found that students who were assigned teachers with higher value-added ratings ended up being “more successful in many dimensions,” including college graduation rates, earnings, and savings.
On average, the study says, having a teacher with a high value-added rating (in the top five percent) for one year raises a student’s lifetime income by $50,000. Replacing a teacher who has a low value-added rating with a teacher of just average quality, according to the study data, could mean earnings gains of as much as $52,000 per student—or more than $1.4 million for the class as a whole.
The findings, according to the study’s authors, show that “great teachers create great value and that test score impacts are helpful in identifying such teachers.” However, they also cautioned that use of value-added ratings in teacher evaluations could “induce counterproductive responses … such as teaching to the test or cheating.”
