Sensitivity Analysis
Shadow Prices, Tornado Plots, and What-If Modeling Under Uncertainty — A TLDR Primer
You have a linear programming problem on your exam and the solver spit out shadow prices, reduced costs, and allowable ranges — and you have no idea what any of it means. Or you need to build a what-if model for class and you don't know where to start. This guide cuts straight to what you need.
**Sensitivity Analysis: Shadow Prices, Tornado Plots, and What-If Modeling Under Uncertainty** is a concise, no-filler primer for high school and early college students tackling sensitivity analysis for the first time. It covers one-way and two-way what-if tables, the shadow price and reduced cost output that every LP solver produces, tornado diagrams for ranking which inputs actually matter, and the difference between local perturbation and full Monte Carlo simulation across an uncertainty space.
Every concept comes with worked numbers, plain-language definitions, and explicit callouts for the misconceptions that trip students up most — like confusing a shadow price with a variable's coefficient, or thinking a tornado diagram requires simulation software.
This is the guide for students in AP Statistics, introductory operations research, managerial economics, or any quantitative course where models meet real-world uncertainty. No prerequisites beyond basic algebra. Short by design, stripped to essentials, and built around the problems you actually have to solve.
If sensitivity analysis is on your syllabus, pick this up and get oriented today.
- Define sensitivity analysis and explain why it matters when model inputs are uncertain
- Interpret shadow prices, reduced costs, and allowable ranges from a linear programming solution
- Perform one-way and two-way what-if analysis on a simple decision model
- Build and read a tornado diagram to rank inputs by their impact on an output
- Distinguish local sensitivity from global sensitivity and recognize when each is appropriate
- Apply sensitivity reasoning to real problems in business, engineering, and policy
- 1. What Sensitivity Analysis Is and Why You Need ItIntroduces sensitivity analysis as the study of how an output changes when inputs change, and motivates it with the uncertainty baked into every real model.
- 2. One-Way and Two-Way What-If AnalysisWalks through changing one input at a time, then two at a time, using a small profit model to show how to build sensitivity tables and read them.
- 3. Sensitivity in Linear Programming: Shadow Prices and Reduced CostsExplains how LP solvers report sensitivity information — the shadow price of a constraint, the reduced cost of a variable, and the allowable ranges over which the current solution stays optimal.
- 4. Tornado Diagrams and Ranking Inputs by ImpactShows how to build a tornado plot to compare which inputs swing the output most, and how to use it to focus effort on the variables that actually matter.
- 5. Local vs. Global Sensitivity and Monte CarloDistinguishes small-perturbation (local) sensitivity from sampling across the full uncertainty space (global), and introduces Monte Carlo simulation as the standard global tool.
- 6. Where Sensitivity Analysis Shows Up in the Real WorldSurveys applications across business, engineering, public policy, and science, and gives practical advice on which technique to reach for first.