The most reliable way to evaluate teachers is to use a three-pronged approach built on student test scores, classroom observations by multiple reviewers and teacher evaluations from students themselves, the foundation found.
The large-scale study is the first to demonstrate that it is possible to identify great teaching, the foundation said.
Researchers videotaped 3,000 participating teachers and experts analyzed their classroom performance. They also ranked the teachers using a statistical model known as value-added modeling, which calculates how much an educator has helped students learn based on their academic performance over time. And finally, the researchers surveyed the students, who turned out to be reliable judges of their teacher’s abilities.
They used all that data to identify teachers who seemed effective. And then they randomly assigned students to those teachers for an academic year. Teachers who seemed to be effective were, in fact, able to repeat those successes with different students in different years, the researchers found. Their students not only scored well on standardized exams but also were able to handle more complicated tests of their conceptual math knowledge and reading and writing abilities.
Researchers found that multiple classroom observations of teachers by several people — a principal, a peer, an outside expert — result in the most accurate assessments. Many school districts currently rely on observations by just one person, usually a principal.
For decades, teacher evaluations were little more than a formality in most school systems, with most educators getting top ratings based on little more than a principal’s checklist. Tenure, rather than student achievement, largely determined whether a teacher was rehired at the end of a school year.