Instructional coaching has become a popular form of support for enhancing educator quality worldwide.  Despite this trend, limited assessments are available that identify instructional coaches' strengths and areas for improvement and track progress in coach practices following intervention. This void in formative assessments for coaches warrants development and validation efforts.  This paper present findings from a study examining psychometric evidence for the iCoach Assessment System (Reddy, Glover, Kurz & Elliott, 2015), an on-line, multi-rater, 360 evaluation tool for assessing the quality of data-based instructional support (i.e., coaching) to assist teachers in meeting the needs of all students, including those with disabilities.  The central component of this system is an action- (A) and outcome- (O) focused behavior rating scale that is completed by a coach, the teachers served by the coach, and the coach’s supervisor. The iCoach system includes a total score, three factor scores, and 18 cell scores. The iCoach was found to yield strong internal consistency (alphas ranging from .97 to .99). The measure also yields acceptable item-to-scale total correlations, exceeding .70 on average (Crocker & Algina, 1986).  As hypothesized, principal axis factoring (using varimax rotation) revealed multiple factors within proposed scales (i.e., Instructional Quality, Positive Behavior Management, and Responsive Learning Communities).  Validation research and directions for educator evaluaton will be outlined.