Arne and Michelle vs. Larry: The Statistical Battle

By Robert Plants
Editor, Schools for the 21st Century

I opened my newspaper this morning to an article titled “ACT Scores Dropping but More Students Are Prepared for College.” I asked myself how is this possible when other reports say that schools and teachers are not preparing students for future learning.

But I’m getting off my topic, which is the research-based finding that “more than 90% of the variation in student gain scores is due to the variation in student-level factors that are not under the control of the teacher.”

Another interesting note from those who have evaluated value-added methods and particularly the one used in LA is that there is opportunity for as much as 26% error in teacher ratings. If you want to put it another way, 26% is a large labeling error to make regarding someone’s chosen vocation. It sort of opens one to litigation in my mind.

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