"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:
- 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);
- Home and community supports or challenges;
- Individual student needs and abilities, health, and attendance;
- Peer culture and achievement;
- Prior teachers and schooling, as well as other current teachers;
- Differential summer learning loss, which especially affects low-income children; and
- 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.
'via Blog this'
No comments:
Post a Comment