> Of course, evaluating whether the therapy itself was the relevant factor here is pretty messy. There’s a lot to these classes other than CBT, and on the surface it looks like a lot of these things could have impacted the results: The programs were administered by adults, who could have created a “generic mentorship effect.” Or maybe simply requiring that they show up to class week after week taught participants self control.

Couldn't they control this by having the other group go to a class, but not do anything?