Visualizing Uncertainty

A forecast line without a confidence interval is a lie drawn as a chart. Every prediction has uncertainty. Every estimate has a range. The visualization that hides the uncertainty communicates false precision. Techniques for visualizing uncertainty: confidence bands (shaded area around a forecast line showing the 80% and 95% intervals), error bars (vertical lines showing the range of a point estimate), probability fans (widening bands that show increasing uncertainty further into the future), and gradient encoding (color intensity mapped to probability). Each technique communicates "this is what we expect, and this is how sure we are." The audience can then make decisions calibrated to the actual confidence level, not the false precision of a single line.