Sparring With Tyson
And, no, I'm not Tyson...
Bruce Baker has an important but somewhat technical post up about the methods that are used to analyze test scores so they can be used for either high-stakes or low-stakes decisions. The reason for the post is that Bruce has seen some corporate "reformers" make the case that Student Growth Percentiles (SGPs) are better at estimating teacher effectiveness than Value-Added Modeling (VAM).
A very short and incomplete summary of the issue is that VAM at least tries to account for student characteristics (and does a miserable job), while SGP doesn't even make the attempt. OK, pretty knotty stuff, but I encourage you to read the post.
I've not seen anyone make this argument myself, although you could say some of the wording
Bruce Baker has an important but somewhat technical post up about the methods that are used to analyze test scores so they can be used for either high-stakes or low-stakes decisions. The reason for the post is that Bruce has seen some corporate "reformers" make the case that Student Growth Percentiles (SGPs) are better at estimating teacher effectiveness than Value-Added Modeling (VAM).
A very short and incomplete summary of the issue is that VAM at least tries to account for student characteristics (and does a miserable job), while SGP doesn't even make the attempt. OK, pretty knotty stuff, but I encourage you to read the post.
I've not seen anyone make this argument myself, although you could say some of the wording
