Classroom observations — a key part of teacher evaluation systems — are biased against teachers with low-achieving students, concludes a new Brookings study of four school districts.
Teachers with students with higher incoming achievement levels receive classroom observation scores that are higher on average than those received by teachers whose incoming students are at lower achievement levels, and districts do not have processes in place to address this bias. Adjusting teacher observation scores based on student demographics is a straightforward fix to this problem. Such an adjustment for the makeup of the class is already factored into teachers’ value-added scores; it should be factored into classroom observation scores as well.
In addition, “observations conducted by outside observers are more valid than observations conducted by school administrators.”
Some teacher evaluation plans include a value-added measure for the school as a whole. This lowers the score of good teachers in bad schools and raises scores for bad teachers in good schools, Brookings concludes.
Only 22 percent of teachers in the study were evaluated on test score gains, notes the report. All teachers are evaluated based on classroom observation.