In the WaPo, Lindsey Layton reports
A new study of 10,000 teachers found that professional development — the teacher workshops and training that cost taxpayers billions of dollars each year — is largely a waste.
The Null Hypothesis is this:
1. Take any educational intervention
2. Conduct a rigorous controlled experiment.
3. Look for results that do not fade out within a year or two.
4. If you find apparent success, try to replicate it
5. You will not find significant effects in all of steps (1) – (4)
For teacher training to work, you have to deal with the null hypothesis at two layers. First, you have to find an intervention that significantly affects teachers. Then that intervention has to significantly effect students. This is the null hypothesis compounded. In Building a Better Teacher, education journalist Elizabeth Green claims that some methods of teacher training survive (1) – (3), but I remained skeptical of (4). Green was interviewed by Russ Roberts in an econtalk episode about a year ago.