Gates Foundation Wastes More Money Pushing VAM. – G. Glass

Glass, Gene V.  “Gates Foundation Wastes More Money Pushing VAM.”  Blog: Education in Two Worlds.  January 14, 2013.  Retrieved from:

Professor Glass, an education researcher and professor in the School of Education and National Education Policy Center at the University of Colorado Boulder, and Emeritus Regents’ Professor at Arizona State University questions the obvious data manipulation used in the latest value-added study funded by the Bill and Melinda Gates foundation.

At the center of the brief’s claims are a couple of figures (“scatter diagrams” in statistical lingo) that show remarkable agreement in VAM scores for teachers in Language Arts and Math for two consecutive years. The dots form virtual straight lines. A teacher with a high VAM score one year can be relied on to have an equally high VAM score the next, so Figure 2 seems to say.

Not so. The scatter diagrams are not dots of teachers’ VAM scores but of averages of groups of VAM scores. For some unexplained reason, the statisticians who analyzed the data for the MET Project report divided the 3,000 teachers into 20 groups of about 150 teachers each and plotted the average VAM scores for each group. Why?


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