Every interval is a contract: the midpoint is your best shot; the arms admit drift. Say it out loud. “Our launch window is ten weeks ± two.” “Screen time is five and a half hours ± one.” The margin isn’t garnish… it’s the lever. Want certainty? Pay with a wider margin. Want precision? Pay with better measurement and more data. If the margin doesn’t change what you do next, you measured a trivia contest, not a decision.
