First-of-its-kind study measures college instructor quality


First-of-its-kind study measures college instructor quality
Effective teachers boost grades and test scores, in both their own and subsequent courses

May 4, 2017—A new, first-of-its-kind study reveals the impact of instructor effectiveness on student achievement in the higher education sector. In an article for Education Next, Pieter De Vlieger, Brian A. Jacob, and Kevin Stange of the University of Michigan report that students taught by skilled postsecondary instructors receive higher grades and test scores, are more likely to succeed in subsequent courses, earn more credits, and are better positioned to complete a college degree, with larger effects for in-person than online classes. These findings suggest that personnel policies designed to promote instructor effectiveness can improve multiple outcomes for college students.

The researchers studied a sample of 339,844 University of Phoenix students enrolled in 26,384 sections of Math I, a required undergraduate mathematics course offered both in-person and online. These courses were taught by 2,243 different instructors between January 2001 and July 2014. The study found that compared to having an average instructor, having an effective instructor (one at the 87th percentile) benefits students in a number of ways:

Grades. Having an effective instructor in Math I boosts students’ grades by 0.30 standard deviations in that course and by 0.20 standard deviations in the subsequent course in the math sequence. The impact of having an effective Math I instructor is larger and longer-lasting for in-person classes than online classes. (See figure.)

Test Scores. Instructors’ effects are even larger when standardized test scores are the measure of student outcomes. For in-person classes, an effective instructor in Math I lifts test scores in that course by 0.49 standard deviations, as well as test scores in Math II by 0.48 standard deviations. In online classes, an effective instructor in Math I improves test scores by 0.14 standard deviations in that course and by 0.05 standard deviations in Math II. (See figure.)

Credits. Students with more effective instructors in Math I are more likely to take the subsequent course in the math sequence and complete more credits overall in the following six months. The impact of having an effective instructor is roughly twice as large for in-person classes as online classes.

Additionally, although student end-of-course evaluations are the primary metric through which college instructor effectiveness is currently judged, the authors find that the student end-of-course evaluations in their sample fail to truly differentiate between effective and ineffective instructors.

Previous to this study, relatively little was known about the impact of teacher quality in higher education because common postsecondary curricula and standardized assessments are rare. But for this study the researchers had the opportunity to examine data from the University of Phoenix, which follows a common instructional model with standardized curricula and assessments for both online and face-to-face classes.

To receive an embargoed copy of “Measuring Up: Assessing instructor effectiveness in higher education” or to speak with the authors, please contact Jackie Kerstetter at The article will be available Tuesday, May 9 on and will appear in the Summer 2017 issue of Education Next, available in print on May 24, 2017.

About the Authors: Pieter De Vlieger is a graduate research assistant at the University of Michigan. Brian A. Jacob is the co-director of the Education Policy Initiative (EPI) at the University of Michigan, where he is a professor of education policy, economics, and education. Kevin Stange is an assistant professor of public policy at the University of Michigan.

About Education Next: Education Next is a scholarly journal committed to careful examination of evidence relating to school reform, published by the Hoover Institution at Stanford University and the Harvard Program on Education Policy and Governance at the Harvard Kennedy School. For more information, please visit

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