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
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).