Teachers Matter: The Need for a Growth-Based Teacher Evaluation System

Evaluation systems can do much more than just measure teacher performance…and they should.

The United States is uniquely positioned to achieve measurable gains in student performance, though it will require a fundamental shift in both perspective and policy. Research shows that teachers—not books, not technology, not buildings, and not even class size—are the single most powerful driver of student performance. Better teachers, better students.

In The Widget Effect, Weisberg and colleagues (2009) noted that most teacher evaluation systems do little, if anything, to address the effectiveness of individual teacher’s instructional strategies. Toch and Rothman (2008) levied heavy criticism at traditional evaluation practices, adding that they are “superficial, capricious, and often don’t even directly address the quality of instruction, much less measure students’ learning” (p. 1). A 2012 report from the Bill and Melinda Gates Foundation, Gathering Feedback for Teaching, took aim at common teacher evaluation systems:

The nation’s collective failure to invest in high-quality professional feedback to teachers is inconsistent with decades of research reporting large disparities in student learning gains in different teacher’s classrooms (even within the same school). The quality of instruction matters and our schools pay for little attention to it. (p. 3)

There is a considerable gap between what research knows and what US educational policies do.  As Hiebert and Morris wrote in 2012:

The history of U.S. education is filled with efforts to improve schools and classrooms (Tyack & Cuban, 1995)…..The U.S. approach frequently has focused on improving the quality of the teachers (Kennedy, 2010). This approach includes recruiting people with the right characteristics (e.g., distinguished academic records, strong content knowledge, high motivation, desirable personality traits; e.g., teachforamerica.org), training preservice and inservice teachers to acquire these characteristics, and removing teachers who are presumed not to exhibit them as evidenced by their poor performance (usually measured by students’ achievement scores; Klein et al., 2010)…the United States persists with this approach even though the data linking any of the characteristics mentioned above with students’ learning are weak (pp 92-93).

Nye and colleagues’ (2004) research suggests the difference between a teacher at the 25th percentile and a teacher at the 75th percentile is 14 percentage points in reading and 18 percentage points in mathematics. In a study of achievement scores from more than 100,000 students across hundreds of schools, Wright and his colleagues (Wright et al, 1997, p. 63) found that “Effective teachers appear to be effective with students of all achievement levels, regardless of the level of heterogeneity in their classrooms.”

Teacher evaluation lies in more than collecting static pictures of how well teachers perform in any given moment. A growth-based teacher evaluation model helps teachers improve their instruction over time, leading students to ever-higher achievement.

For more on the dual purposes of evaluation systems: measuring teacher performance and developing teacher expertise, see Dr. Marzano’s article in November’s Educational Leadership.



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