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Make sure you read all parts 1-3!

“I made a scatter plot of the 5,675 teachers. On the x-axis is that teacher’s language arts score for 2010. On the y-axis is that same teacher’s math score for 2010. There is almost no correlation.

Rather than report about these obvious ways to check how invalid these metrics are and how shameful it is that these scores have already been used in tenure decisions, or about how a similarly flawed formula will be used in the future to determine who to fire or who to give a bonus to, newspapers are treating these scores like they are meaningful. The New York Post searched for the teacher with the lowest score and wrote an article about ‘the worst teacher in the city’ with her picture attached. The New York Times must have felt they were taking the high-road when they did a similar thing but, instead, found the ‘best’ teachers based on these ratings.

I hope that these two experiments I ran, particularly the second one where many teachers got drastically different results teaching different grades of the same subject, will bring to life the realities of these horrible formulas. Though error rates have been reported, the absurdity of these results should help everyone understand that we need to spread the word since calculations like these will soon be used in nearly every state.”

Analyzing Released NYC Value-Added Data Part 2 by Gary Rubinstein.