The Challenge of Measuring Instructional Coach Effectiveness

Teacher coaching has the potential to improve instructional quality and student learning. However, little research explores measures of coach effectiveness. The current study examines the properties, assumptions, correlations, and predictors of five measures of instructional coach quality in a large, district-wide coaching program. We consider three professional ratings of coaches, including assessments from school leaders, mentee teacher surveys, and coach self-assessments. We also construct measures of a coach’s value-added to their mentee teachers’ observation scores and those teachers’ students’ test scores. We find that all five measures have substantial limitations including limited construct coverage, bias, and imprecision. We also find few correlations among the five measures and few predictors of these measures. Implications for future research on coaching and coach effectiveness are discussed.