I neglected to give the source for the data for my last two posts. It’s at the website for what looks like a NYC radio or TV station:
if you prefer it shorter.
I will warn you that some of the spreadsheets are quite large.
BTW, I just now did a graph showing how well New York City does at predicting the value-added scores of its teachers for school year 2007-2008. The answer seems to be, not very well. Here is the scatter plot:
The correlation is, again, close to zero, even though NYC’s department of assessment and numerology has done their best to try to get it right. In fact, even though the line of best fit doesn’t fit very well, you notice that it slopes downwards to the right. That means that with kids who are predicted to improve relative to the previous year, teachers’ value-added scores are, in general, lower than predicted; whereas with kids who are predicted to do worse than the previous year, teachers’ value-added scores are, in general, a tad higher than predicted.
Not ready for prime time. And not ready to be used to base hiring and firing and bonus decisions on.