The Wheatley Institution

Fellow Notes


We Know Quality Teaching Is Critical…But How Do We Bring It About?

“Teacher quality has the biggest impact on a student's growth.”

Donald Deshler | October 19, 2015
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A teacher instructs a classroom full of students, trying to improve his skills to create a quality learning environment



If you had to make a choice of one factor that impacts student’s academic achievement the most, which one would you choose: (1) the school the student attends, (2) the teacher(s) the student has, or (3) the characteristics (e.g., dispositions, intelligence, etc.) of the student? The correct answer isn’t close at all: it’s the teacher(s) that the student has. When it comes to improving student achievement, teacher quality matters most. Numerous studies have shown that no other school factor (e.g., school, curriculum, class size, amount of technology) has a greater impact on student achievement than the quality of a student’s teacher.

The work of Bill Sanders and his team, formerly of the University of Tennessee's Value-Added Research and Assessment Center, has underscored the importance of the individual teacher on student learning. When studying the additive or cumulative effect of teacher effectiveness on student achievement, Sanders looked at what happened to students whose teachers produced high achievement versus those whose teachers produced low achievement results.

He found that when children, beginning in 3rd grade, were placed with three high-performing teachers in a row, they scored on average at the 96th percentile on Tennessee's statewide mathematics assessment at the end of 5th grade. When children with comparable achievement histories starting in 3rd grade were placed with three low-performing teachers in a row, their average score on the same mathematics assessment was at the 44th percentile – a remarkable 52-percentile point difference for children who had comparable abilities and skills (Sanders & Rivers, 1996)!

It's obvious that developing such [Highly Effective] teachers should be one of our top priorities

Given that highly effective teachers make such a difference in student achievement, it’s obvious that developing such teachers should be one of our top priorities. As straightforward as that may seem, the startling findings of a newly released report show that many of the things that we thought were central to developing highly effective teachers don’t seem to be true! For years, we’ve assumed that we knew what quality professional development looks like. We assumed that the only challenge was being able to effectively scale what we know.

The report, The Mirage: The Hard Truth About Our Quest for Teacher Development (2105), discounts that assumption. This report, based on an in-depth study of professional development practices in three large school districts and one midsize charter school network, surveyed more than 10,000 teachers, 500 school leaders, and over 100 staff members involved in teacher development.

Among the major findings were the following:

          • Districts are making massive investments in teacher improvement – Nearly $18,000 is spent on each teacher annually. One district is spending more on staff development than transportation, food, and security combined. It is estimated that the 50 largest school districts in the U. S. spend nearly $8 billion/year on professional development. Additionally, each teacher spends about 19 full school days/year participating in staff development activities.

            • Despite these expenditures and efforts, most teachers do not appear to substantially improve in their instructional effectiveness from year to year – Nearly seven out of 10 teachers remained constant or declined in their demonstration of critical teaching skills. As many as half of the teachers studied in there 10th year or beyond were rated below “effective” in core instructional practices.

       • Even when teachers do improve, researchers were unable to link their growth to any particular development strategy – Dozens of variables were investigated to find a link to positive teacher growth on key instructional behaviors including types of development activities teachers experienced, how much time they spent on them, how much coaching supports that they received, or what mindsets they brought to their teaching. No common factors emerged that distinguished what the researchers called “improvers” from teachers who didn’t show improvement. In short, no amount or combination of development activities appeared more likely than any other to help teachers improve substantially, including practices that have been recently heralded as among the most promising professional development practices such as “differentiated” or “job-embedded” experiences.

As a result of these surprising findings, the researchers concluded the following: “It’s time to take a step back in our pursuit of teacher improvement and acknowledge just how far we stand from the goal of great teaching in every classroom, even as we recommit ourselves to reaching it. We have no excuses—we cannot blame a lack of time, money or good intentions. Instead, we must acknowledge that getting there will take much more than tinkering with the types or amount of professional development teachers receive, or further scaling other aspects of our current approach. It will require a new conversation about teacher development— one that asks fundamentally different questions about what better teaching means and how to achieve it.” (p. 3)


Jacob, A., & McGovern, K. (2015). The Mirage: The Hard Truth About Our Quest for Teacher Development. Brooklyn, NY: TNTP.

Sanders, W. L., & Rivers, J. C. (1996). Cumulative and residual effects of teachers on future student academic achievement (Research Progress Report). Knoxville, TN: University of Tennessee Value-Added Research and Assessment Center.