Most children with ADHD can tell you exactly what they should have done. The knowing was never the missing piece, which is why a course teaching the knowing changes so little.

What the research says

A meta-analysis of randomised trials of cognitive training in ADHD found improvements on some neuropsychological measures, while the effects on symptoms largely disappeared once the raters were blind to who had been trained. That is the same shape as the problem here, where something improves inside the training and much less improves outside it. It tested a different kind of training, so it is a warning about transfer rather than a direct test of social skills teaching.

Strength of evidence: one line of research. A single study, or a theoretical account.