The Performance Assessment for Leaders (PAL) was developed by a team of nationally recognized experts in response to a Massachusetts requirement to determine and evaluate the leadership abilities of candidates seeking initial school principal licensure. This article describes and evaluates research conducted on all aspects of a 2014-2015 statewide field trial of PAL. Findings suggest that this assessment is a valid and reliable measure of individual candidate competence for granting initial school leader licensure, and is a positive, educative experience for candidates. It concludes with implications for use elsewhere.