Is School Value-Added Indicative of Principal Quality?

Existing research that estimates principals’ effects on student achievement has employed value-added models that have only limited usefulness for actual performance evaluation systems. Principals’ effects are typically identified through school leadership changes, meaning that effectiveness data cannot be generated for all principals and that effects are comparable only within small groups of schools connected by principal transfers. In contrast, school value-added estimates, which are more commonly used to evaluate principals in practice, can be generated for all principals but include multiple influences beyond principal quality. We examine the extent to which school value-added is a valid indicator of elements of principals’ effectiveness that persist over time and impact multiple grades—elements that manifest principals’ general leadership skills. Using longitudinal data on the math and reading outcomes of 4th through 8th grade students in Pennsylvania, our findings indicate that school value-added provides little useful information for comparing the general leadership skills of different principals when those comparisons include some principals who are in their first three years at their current positions.