Here are the key findings in Texas against the use of VAM for evaluating teachers:
- The VAM system which was originally designed to measure farm efficiency is not comparable to teaching effectiveness.
- The American Statistical Association found that the impact of teacher quality on student scores was 14% at most. All the other factors such as socioeconomic deficiencies make the teacher portion almost insignificant in determining VAM.
- Some administrators were found to be basing the teacher observation portion of the teacher evaluation on the teacher's VAM score which totally invalidated the observation portion.
- High stakes tests which are used as the basis for VAM were never designed for teacher evaluation.
- The stability of VAM scores was found to be so erratic that it could not be relied upon to reliably evaluate teachers.