As the political heat builds up to find a way to judge the competency of  teachers, the value-added modeling (VAM) statistical formula was created to answer the accountability call.

For a peak at the actual formula, and how it is affecting teachers, go to this article by Michael Winerip at the New York Times titled, “Evaluating New York Teachers, Perhaps the Numbers Do Lie.” Here you will also read about the huge amount of error in the scores, and how they can fluctuate wildly from year to year.

Since VAM will be used, indeed, has been used, to affect teacher’s careers, wouldn’t it be nice if it was shown to be a valid tool for assessing performance?  Unfortunately, this is not the case. As with so much education reform today, ideas are pushed into practice before the ramifications are fully known. continue reading…