If by now you don’t know what VAM is, you should. It’s shorthand for value-added modeling (or value-added measurement), developed by economists as a way to determine how much “value” a teacher brings to a student’s standardized test score. These formulas are said by supporters to be able to factor out things such as a student’s intelligence, whether the student is hungry, sick or is subject to violence at home, or any other factor that could affect performance on a test beyond the teacher’s input. But assessment experts say that such formulas can’t really do that accurately and reliably. In fact, the American Statistical Association issued a report in 2014 on VAM and said: “VAMs are generally based on standardized test scores and do not directly measure potential teacher contributions toward other student outcomes.” click here for full article: Via The Washington Post