How did we miss this one?

Mike the Biologist links to a remarkable statistic:

There are numerous problems with using VAM scores for high-stakes decisions, but in this particular release of data, the most obvious and perhaps the most egregious one is this: Some 70 percent of the Florida teachers received VAM scores based on test results from students they didn’t teach and/or in subjects they don’t teach

.Even more remarkable, this was only revealed after a court ordered the Florida Times-Union sued for access to the records.  The source also notes that this issue is live in Tennessee, which has similar problems.  Now we have a lot of moving parts in the area of education reform and there are arguments about the use of value added measures (VAM) testing. 

But nobody has a good argument about testing other teachers and making employment decisions based on their performances.  When we talk about peer effects, it is the students in the classroom and not colleagues that we are thinking of.  It is also striking how much room there is to game statistics when you only collect real data on one third of teachers.  Can we really presume that this data collection is a proper random sample? 

These issues are not necessarily small issues.  They have the potential to replace one set of issues in education with another.  Nor is it 100% clear that they address the issue of social mobility, either, as less job security for teachers does not appear to directly address the drivers of intergenerational social mobility. 

I have respect for people trying to solve a tough problem, but this does not seem to be a great way to go.