Chart - Sensitivity Tornado.

Best for: Sensitivity analysis on a financial model, testing price and churn assumptions, ranking risk variables, presenting downside risk up front at an investment committee, auditing business plan assumptions

Use: When you need to compare how far three to six variables swing one result (operating profit, NPV, CAC) so you can decide which assumption deserves management attention. Use it in business plans, investment committees, and pricing decisions where the point is not the number itself but what the number depends on. Two preconditions are mandatory. First, the bars must be sorted in descending order of the sum of their two lengths, otherwise the tornado shape, and with it the sensitivity ranking, falls apart. Second, the footnote on the left must state that the same swing (plus/minus N%) was applied to every variable, because unequal swings make the bar-length comparison meaningless.

Avoid: Use chart-waterfall-bridge for the path from a starting value through increments to an ending value, since its bars accumulate in sequence and sum to the end value, while the five variables here are independent single swings that do not add up. Use chart-mix-shift-columns for a shift in composition, problem-benchmark-gap for the gap between our number and an industry benchmark, problem-risk-matrix for an impact-by-likelihood grid, chart-bar for one-directional comparison with no negative side, and chart-slope-comparison for per-item change between two points in time. Two variables or fewer will not form a tornado, and seven or more push the bar height under 20px so the figures stop being readable. Do not use it for analysis that needs a different swing per variable.