I'm not saying it isn't a win, necessarily. I'm saying we don't know if the training is what's causing the win, or if it's just the different demographic. Maybe you could get the exact same effect by either raising the driving age to 21, or keeping the driving age the same but otherwise (through fees and other burdens) discouraging people under 21 from driving. If that were the case (and I have no idea if it is or not), then you'd be unnecessarily costing people time and money, to no good effect.