HKSM

A bar-chart style sensitivity analysis tool that ranks input variables by how strongly they affect the result, enabling quick comparison of their relative influence.

Key Points

• Shows how much the output changes when each variable is moved between low and high values.
• Bars are sorted from greatest to smallest impact, typically centered on the base case.
• Used in quantitative risk and decision analysis to prioritize which assumptions matter most.
• Helps direct mitigation and data-gathering efforts to the most influential uncertainties.

Example

A project team evaluates cost estimate sensitivity by varying labor rate, material price, productivity, and rework percentage between pessimistic and optimistic bounds. The tornado diagram displays bars for each factor, sorted by how much each shifts total project cost, revealing that productivity and labor rate dominate the estimate and deserve focused risk responses.

PMP Example Question

Which tool should a project manager use to visually rank uncertain input variables by their impact on the project's cost estimate during sensitivity analysis?

1. Tornado diagram
2. Scatter diagram
3. Cause-and-effect (fishbone) diagram
4. Control chart

Correct Answer: A — Tornado diagram

Explanation: A tornado diagram is a specialized bar chart used in sensitivity analysis to compare the relative importance of variables by ordering them by their effect on the outcome.