Good principals can make a big difference
“It is widely believed that a good principal is the key to a successful school.” So say Branch, Hanushek, and Rivkin in their study of school principals on learning productivity. But how do you measure this? Using a database from Texas in the United States, they employ a value-added approach analogous to that used to measure performance among teachers. They control for basic information on student backgrounds (gender, ethnicity, and an indicator of poverty) as well as student test scores from the previous year. Then they ask, What happens to student learning when a school changes principals? They find that increasing principal quality by one standard deviation increases student learning by 0.11 standard deviations. Even after additional adjustments, their most conservative estimates show that “a 1-standard-deviation increase in principal quality translates into roughly 0.05 standard deviations in average student achievement gains, or nearly two months of additional learning.”
Notably, while improving teacher effectiveness affects the average performance of all of the students in his class, improving principal effectiveness affects average performance of the entire school, so the potential gains are high.