It's been said several times already, but because it's so important I feel compelled to chime in. Especially in the first year, if they find a friend in the troop, a buddy, someone they look forward to sharing at tent with, they will likely stay. If not, most will stop coming. At that age they are still children, and they want to have fun. If your son has some interest in Scouting, improve his chances of staying with the program by convincing one of his friends who also has an interest to join with him. Friends made in Scouting tend to be lifelong friends because of the shared experiences.