Suppose you're expected to be in a particular place, but you keep wandering off. Well, if you keep wandering, and you wander randomly enough, you'll pass through the place you're supposed to be occasionally. Someone whose job it is to evaluate whether you're where you're supposed to be, and who always goes to look for you at that spot, will conclude that you're there, but not often enough.
Now suppose you could take a pill that makes you walk faster. Makes you run, even. You'll still wander, but you'll pass through that spot more frequently. Someone checking that spot will conclude that the pill makes you better able to stay where you're supposed to be.
So, how about you?
Are you feeding your kids amphetamines?