Thoughts on how what we measure drives behavior — My three-and-a-half-year-old son, Evan, has decided that he’s just not that interested in getting out of diapers. He’s our last, and we’re ready to stop funding Pampers, so we’ve resorted to the most time-honored of parenting tools: bribery. Each time he pee-pees in the potty, he gets to watch a…