States and districts across the country are implementing new principal evaluation systems that include measures of the quality of principals’ school leadership practices and measures of student achievement growth. But there is little evidence about whether these measures provide accurate information about principals’ performance.

This study, conducted for the Regional Educational Laboratory Mid-Atlantic, finds both strengths and limitations in the measures used for New Jersey’s principal evaluation system. New Jersey conducted a pilot of its principal evaluation system in 14 school districts in 2012/13. The study’s analyses of pilot data indicate that principal practice ratings and schoolwide student achievement growth vary across principals and thus have the potential to distinguish effective and ineffective principals. However, schoolwide student achievement growth changed little at schools that changed principals and was lower at schools with more disadvantaged students. The developers of the principal practice instruments provided only partial information about the accuracy of the scores produced by these instruments.

Information about the properties of the evaluation measures can inform modifications of the principal evaluation system or revisions to the guidance that the state provides districts.