A confidence interval isn’t “the range where the truth lives.” It’s a contract: repeat this method forever, and this style of interval would catch the truth at your chosen rate. That’s it. Want tighter bounds? Pay with more data or more discipline; don’t pay with wishful thinking. Before you compute anything, ask: what margin would change my action? If ±3 changes staffing but ±8 doesn’t, design for ±3. Report both dialects (estimate ± margin and lower–upper) so leaders and analysts hear you. And always label what the interval describes: a mean, a difference, a proportion, a risk ratio. Intervals are bridges, not banners. Use them to cross from a noisy sample to a useful choice.
