In the research I've seen on in-school programs, the most effective are peer-to-peer. With some of the stuff these folks are doing, peer-to-peer is the most effective, because the students are being spoken to by people their own age. The most effective would be somebody their age who has been charged or has had an accident and can share that. That is the most powerful, effective tool to change kids' attitudes and behaviours.
On September 20th, 2017. See this statement in context.