The Teaching Difference

by | Apr 12, 2019

We count on teachers – classroom teachers as well as counselors, librarians, coaches, and so many others in our schools – to contribute to the academic and personal growth of children in our lives and in our communities.

1st-grade teacher Katrina Glass, Perryville Elementary School

Many of us can track our own life trajectories to teachers who challenged, encouraged, and supported us along the way – inspiring us to persevere through the fourth draft of an essay, to audition for the spring musical, to enroll in an advanced math course, to eat more green vegetables (thank you to my seventh grade math teacher Mrs. Travis), to serve the community or nation, to try out for the baseball team, to read and write poetry, and on and on.

Through our stories, our direct experiences, we have an idea about how much teachers matter to student learning and long-term life outcomes.

In the 1970’s and 80’s, a handful of economists such as Eric Hanushek and Richard Murnane began to uncover evidence to verify our experiences. They found that although the socioeconomic background is highly correlated to academic achievement and educational attainment for children and youth in the United States, when you look at learning gains over time, teachers make a substantial difference.

A statistician at the University of Tennessee, Bill Sanders, identified similar results using data from a local school district and then across the state. He found, in fact, that students who have the strongest teachers year after year are more likely to make lasting learning gains. Students who have the weakest teachers year after year, however, struggle to recover.

In the last 20 years, this thread of research has flourished, thanks to the sudden availability of yearly state test results for elementary and middle school students and new infrastructure to analyze an array of student and teacher data over time. It is also a line of research that offers hope to all those who seek to advance policy and practice to improve outcomes for all children while easing disparities in opportunity across children – hope that demographics is far from destiny.

Today, research from numerous economists on the impact of teachers has settled on as much of a consensus as you could ever expect in academic literature.

Looking across the literature, we can conclude the following with reasonable confidence:

  • Teachers make the largest difference in how much students learn over time. Principals and the school as a whole matter as well.
  • We observe more variation in teacher impact on student learning in mathematics than in English.
  • We observe much more variation in teacher impact on student learning within teacher characteristics we can easily observe, such as certification pathway and educator preparation program, teacher certification exam scores, and advanced degrees, than we do across these characteristics. In other words, these characteristics do not explain very much about teacher impact on student learning.
  • The only major exception to the above is that new teachers tend to make less impact on student learning than teachers with several years of experience. On average, the returns from additional years of experience diminish after three to five years.

I also recommend a few articles from EducationNext in which scholars describe more recent research:

  • Raj Chetty, Jon Friedman, and Jonah Rockoff describe their research that suggests that teacher impact on student learning (as measured by test scores) translates into long-term outcomes for students, such as college attendance, steeper earnings trajectories, less chance of having a child while a teenager, and increased participation rates in 401(k) plans. They have additional information on the Opportunity Insights website.
  • Kirabo Jackson describes his new paper that shows how teachers impact students well beyond test scores, influencing suspensions and on-time grade progression that translates into 12th grade GPA, high school graduation, and college enrollment.
  • Eric Hanushek, Marc Piopiunik, and Simon Wiederhold have an article summarizing their cross-nation research that finds some evidence that teachers with higher cognitive skills have a greater contribution to student performance within mathematics or reading. (I will return to this article in my next blog post on teacher pay.)

Now that we know that hard research backs up that teachers matter a great deal to learning and long-term life experiences, what do we do in Kentucky?

First, we need to acknowledge that in the last 10-12 years, this research has emerged alongside a flurry of policy and funding to explore different methods of recruiting, retaining, preparing, evaluating, compensating, and advancing teachers. We need to learn from this era of active policy change and implementation to inform any new policy development.

Second, we need to continue asking hard questions. Here are two that come to mind for me:

  • How will we prevent systematic disparities across students in exposure to the teachers who make a large positive difference in student learning, behavior, and later life outcomes?
  • How will we support systems that encourage and support teachers, individually and collectively, to keep improving their impact on student learning, behavior, and later life outcomes?


Since 1983, the Prichard Committee has worked to study priority issues, inform the public and policy makers about best practices and engage citizens, business leaders, families, students, and other stakeholders in a shared mission to move Kentucky to the top tier of all states for education excellence and equity for all children, from their earliest years through postsecondary education.

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