Thursday, January 10, 2013

Sometimes I need to read more clearly

I had noted that the presence of defined benefit versus defined contribution pension plans in the evaluation of state education systems.  This was obviously hard to fathom as the way you handle retired teachers seems to have limited predictive ability for the quality of education.  I had not realized it was an anchor category:

 Amazingly, the methodology being used by Rhee’s grifters gives states a “4″ (the highest score) if they have defined contribution pensions and a “0″ if they have defined benefit pensions. In other words, states get higher rankings for their education systems if they make their pension benefits less attractive! Even more amazingly, pension “reform” is an “anchor” category, meaning it gets three times the weight of some of the other categories that might actually have a clear positive relationship with improving a state’s educational system.

So even if you thought there was some small effect here (older teachers hanging on for a couple of extra years to improve their pensions who could easily have found a job elsewhere?), it's hard to imagine that this is a key metric that should be given special weight.

This sort of revelation really does point out the problem with models: bad data in, bad results out.  

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