Teachers’ impact on student behavior matters more for student success than their impact on test scores
Current value-added models are insufficient to identify truly excellent educators
October 18, 2018— The Every Student Succeeds Act has brought national focus to the importance of nurturing student skills not captured by test scores—such as adaptability, motivation, and self-restraint—to foster success in K-12, college, and careers. But current teacher evaluation systems neglect to measure teachers’ impact on the development of such skills. Are policymakers missing a golden opportunity to identify the most effective teachers? In a new article for Education Next, C. Kirabo Jackson of Northwestern University reports that teachers’ impact on student behavior is 10 times more predictive of students’ long-term academic success than their impact on test scores. Further, teachers who are highly effective at improving student behavior cannot be identified by value-added ratings based on test scores alone.
Jackson analyzed data on all North Carolina public-school 9th-grade students between 2005 and 2012— including demographics, test scores in grades 7 through 9, and codes linking scores to the teacher who administered each test—focusing on the 93 percent (roughly 533,800) of students who took classes in which it was possible to calculate teachers’ value-added to test scores: English I and one of three math classes, algebra I, geometry, or algebra II. Jackson’s measure of students’ non-tested skills, called the “behavior index,” includes a student’s number of absences and suspensions, grade point average, and on-time progression to 10th grade.
Among Jackson’s key findings:
• A student’s behavior index is a much stronger predictor of future success than test scores. A student whose 9th-grade behavior index is at the 85th percentile (one standard deviation above the median) is 15.8 percentage points more likely to graduate from high school on time than a student with an average behavior index score. When it comes to test scores, a student at the 85th percentile is only 1.9 percentage points more likely to graduate on time than a student whose score is at the median. The behavior index is also a better predictor than 9th-grade test scores of high-school GPA and the likelihood that a student takes the SAT and plans to attend college.
• Although teachers who are better at raising test scores tend to be better at raising the behavior index, on average, effectiveness along one dimension is a poor predictor of the other. For example, among the bottom third of teachers with the worst behavior value-added, nearly 40 percent are above average in test-score value-added. Similarly, among the top third of teachers with the best behavior value-added, only 58 percent of teachers are above average in test-score value-added. In other words, knowing a teacher’s skill at improving one dimension provides little insight on their impact on the other.
• Teachers’ impact on behavior is about 10 times more predictive of students’ longer-term success than their impacts on test scores. Having a teacher at the 85th percentile of test-score value-added for a single 9th-grade class increases a student’s chances of graduating high school on time by about 0.12 percentage points compared to having an average teacher. In contrast, having a teacher at the 85th percentile of behavior value-added would increase high-school graduation by about 1.46 percentage points compared to having an average teacher. This pattern holds true for other outcomes examined, including plans to attend college.
Jackson recommends a multiple-measures teacher evaluation system that includes indicators of a broad range of student skills, classroom observations, and evidence of responsiveness to feedback alongside test-based value-added ratings.
To receive an embargoed copy of “The Full Measure of a Teacher: Using value-added to assess effects on student behavior” or to speak with the author, please contact Jackie Kerstetter at email@example.com. The article will be available Tuesday, October 23 on www.educationnext.org and will appear in the Winter 2019 issue of Education Next, available in print on November 16, 2018.
About the Author: C. Kirabo Jackson is professor of human development and social policy at Northwestern University.
About Education Next: Education Next is a scholarly journal committed to careful examination of evidence relating to school reform, published by the Education Next Institute and the Harvard Program on Education Policy and Governance at the Harvard Kennedy School. For more information, please visit www.educationnext.org.