This new paper by edu-economist extraordinaire Eric Hanushek and colleagues adds empirical clout to the “conventional wisdom” that principal quality—and principal turnover—matters for student performance. (This paper debuted at a recent CALDER conference that was chockablock with important education research.) Using administrative data, analysts observed over 7,000 principals from 1995 to 2001 in Texas. They first estimate principals’ contributions by tracking student-learning gains during each leader’s tenure at a given school, controlling for other school-level factors. (They attempt to control for years of experience by limiting one of their analyses to principals with three years under their belts.) According to their most conservative estimates, having a principal in the top 16 percent of the distribution will lead the average student to learn 0.05 standard deviations more than he or she would in a school with an average principal. For comparison, studies suggest that teacher effects are about twice this size, though importantly, the learning effects due to a strong principal apply to all students in the school, not just an individual classroom. Meaning the aggregate impact of having an effective principal in a school can be very large. Further, variance in effectiveness among leaders increases with the school-poverty rate—meaning that the poorest schools are more likely to have either very effective or very ineffective principals. Principal turnover patterns also differ by principal quality and type of school. In other words, analysts find that both the least and most effective principals tend to switch schools more often; this phenomenon is also more pronounced in low-income schools. Unfortunately, the worst principals don’t appear to leave education altogether; they merely resurface as leaders at other schools. It seems that principals, and not just teachers, take part in the “dance of the lemons,” too.
Gregory F. Branch, Eric A. Hanushek, and Steven G. Rivkin, “Estimating the Effect of Leaders on Public Sector Productivity: The Case of School Principals” (Washington, D.C.: National Center for Analysis of Longitudinal Data in Education Research, January 2012).
