Teachers have large effects on students’ academic outcomes, but there is little understanding of which features of teachers and teaching best explain these effects. In this study, we collected 22 measures of teacher and teaching quality from three broad categories: classroom instruction (e.g., quality, content), teacher personal characteristics (e.g., knowledge, self-efficacy), and teacher background (e.g., education, experience). All three categories explained some unique variation in teacher effects, though measures of instruction explained the least, even after correcting for measurement error. Thus, although a diverse set of measures best distinguishes teachers’ effectiveness, a cost-effective starting point might be to focus on the less expensive but relatively information-rich measures of teacher personal characteristics and background.
