Does Professor Quality Matter? Measures of Value-Added

Does Professor Quality Matter? Evidence from Random Assignment of Students to Professors by Scott Carrel and James West present a study of value-added measures, instructor quality, and student achievement using the unique data panel from the U.S. Air Force Academy.
[At the USAFA], students are randomly assigned to professors over a wide variety of standardized core courses. The random assignment of students to professors, along with a vast amount of data on both professors and students, allows us to examine how professor quality affects student achievement free from the usual problems of self-selection…. [P]erformance in USAFA core courses is a consistent measure of student achievement because faculty members teaching the same course use an identical syllabus and give the same exams during a common testing period. Finally, USAFA students are required to take and are randomly assigned to numerous follow-on courses in mathematics, humanities, basic sciences, and engineering. Performance in these mandatory follow-on courses is arguably a more persistent measurement of student learning.
Results show that there are statistically significant and sizable differences in student achievement across introductory course professors in both contemporaneous and follow-on course achievement. However, our results indicate that professors who excel at promoting contemporaneous student achievement, on average, harm the subsequent performance of their students in more advanced classes. Academic rank, teaching experience, and terminal degree status of professors are negatively correlated with contemporaneous value-added but positively correlated with follow-on course value-added. Hence, students of less experienced instructors who do not possess a doctorate perform significantly better in the contemporaneous course but perform worse in the follow-on related curriculum.