Evaluating Teacher Evaluation
The authors conclude: Popular modes of evaluating teachers are fraught with inaccuracies and inconsistencies, but the field has identified better approaches.
Here are a couple of the highlighted points made in the article:
Teachers are advantaged or disadvantaged based on the students they teach.
The notion that there is a stable "teacher effect" that's a function of the teacher's teaching ability or effectiveness is called into question if the specific class or grade-level assignment is a stronger predictor of the value-added rating than the teacher.
Successful systems use multiple classroom observations, expert evaluators, multiple sources of data, are timely, and provide meaningful feedback to the teacher.
By Linda Darling-Hammond, Audrey Amrein-Beardsley, Edward Haertel, and Jesse Rothstein
Practitioners, researchers, and policy makers agree that most current teacher evaluation systems do little to help teachers improve or to support personnel decision making. There's also a growing consensus that evidence of teacher contributions to student learning should be part of teacher evaluation systems, along with evidence about the quality of teacher practices. "Value-added models" (VAMs), designed to evaluate student test score gains from one year to the next, are often promoted as tools to accomplish this goal.
Value-added models enable researchers to use statistical methods to measure changes in student scores over time while considering student characteristics and other factors often found to influence achievement. In large-scale studies, these methods have proved valuable for looking at factors affecting achievement and measuring the effects of programs or interventions.
Using VAMs for individual teacher evaluation is based on the belief that measured achievement gains for a specific teacher's students reflect that teacher's "effectiveness." This attribution, however, assumes that student learning is measured well by a given test, is influenced by the teacher alone, and is independent from the growth of classmates and other aspects of the classroom context. None of these assumptions is well supported by current evidence.
Most importantly, research reveals that gains in student achievement are influenced by much more than any individual teacher. Others factors include:
ΓΆ€ΒΆ School factors such as class sizes, curriculum materials, instructional time, availability of specialists and tutors, and resources for learning (books, computers, science labs, and more);
ΓΆ€ΒΆ Home and community supports or challenges;
ΓΆ€ΒΆ Individual student needs and abilities, health, and attendance;
ΓΆ€ΒΆ Peer culture and achievement;
ΓΆ€ΒΆ Prior teachers and schooling, as well as other current teachers;
ΓΆ€ΒΆ Differential summer learning loss, which especially affects low-income children; and
ΓΆ€ΒΆ The specific tests used, which emphasize some kinds of learning and not others and which rarely measure achievement that is well above or below grade level.
However, value-added models don't actually measure most of these factors. VAMs rely on statistical controls for past achievement to parse out the small portion of student gains that is due to other factors,of which the teacher is only one. As a consequence,
researchers have documented a number of problems
with VAM models as accurate measures of teachers' effectiveness. . . .
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By Linda Darling-Hammond, Audrey Amrein-Beardsley, Edward Haertel, & Jesse
Phi Delta Kappan
INDEX OF RESEARCH THAT COUNTS