How important are school principals in the production of student achievement?

As school leaders, principals can influence student achievement in a number of ways, such as hiring and firing of teachers, monitoring instruction and maintaining student discipline, among many others. We measure the effect of individual principals on gains in math and reading achievement between grades 4 and 7 using a value-added framework. We estimate that a one standard deviation improvement in principal quality can boost student performance by 0.289 to 0.408 standard deviations in reading and math, while the principal at the 75th percentile improves scores by 0.170 to 0.193 relative to the median principal. Our results imply that isolating the most effective principals and allocating them accordingly between schools can have a significant positive effect on reducing achievement gaps.