Education Next – Jason A. Grissom
“Teacher evaluation systems show a stubborn tendency to rate nearly all teachers as effective. This historical fact has remained true even as most states have invested in rigorous new “multiple measures-based” teacher evaluation systems. The primary reason for the lack of variation in teacher evaluation scores in most systems is that teachers tend to score overwhelmingly positively on the instructional or professional practice portion of the evaluation, which usually makes up half or more of the overall evaluation score. Much as in the olden days when teacher evaluations were simple checklists, the principals who assign these subjective ratings just don’t differentiate much.”(more)