[vintermann]

If that would surprise you, you don't know much about social science. Proving an intervention works is one thing, convincing the people who make the decisions to follow up on it is quite another.

Luckily Olweus was uncommonly good at that too. It has been implemented at thousands of schools all across the world, and kept being evaluated in differing cultural contexts, and in comparison to alternative interventions, in many systematic review studies.