Glossary

Sensitivity analysis

Sensitivity analysis examines how changes in input assumptions affect an output, model result, or operational outcome.

Scrap, Rework and Cost of Poor Quality Reduction Quality, NCR, and Continuous Improvement

Sensitivity analysis is a method for evaluating how much an output changes when one or more inputs, assumptions, or parameters are varied. It is commonly used in manufacturing, quality, planning, and analytics to understand which factors have the greatest influence on a result.

In practice, the term usually refers to testing a model, calculation, forecast, or process metric by changing selected variables and observing the effect. Examples include changing demand assumptions in a planning model, adjusting process parameters in a yield model, or examining how scrap rate, cycle time, or supplier lead time affects cost or schedule performance.

Sensitivity analysis does not by itself prove cause and effect, validate a model, or determine the single correct operating setting. It is an analytical technique for understanding responsiveness, uncertainty, and relative influence.

Where it applies

In industrial and regulated operations, sensitivity analysis may appear in:

production planning and capacity scenarios
cost, margin, and inventory modeling
quality and process-improvement studies
risk assessments and contingency planning
engineering and process development work, including design of experiments and simulation

It can be performed with simple spreadsheet models or with more formal simulation, statistical, or optimization tools.

Common confusion

Sensitivity analysis is often confused with scenario analysis and design of experiments.

Scenario analysis usually compares a defined set of combined conditions, such as best case, expected case, and worst case.
Sensitivity analysis focuses on how the output responds when specific inputs are changed, often one at a time or across a defined range.
Design of experiments (DoE) is a structured experimental method used to study factor effects and interactions in real or simulated processes.

It is also not the same as measurement sensitivity, which refers to how responsive an instrument or detection method is.

Manufacturing example

A planner may test how a 5 percent change in forecast demand, supplier lead time, or machine uptime affects required inventory and promised ship dates. A quality engineer may assess how variation in temperature, dwell time, or torque changes predicted defect rates. In both cases, the goal is to identify which inputs matter most and where tighter control or better data may be needed.

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Why are scrap decisions in MRO often harder than in OEM production?

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What role does root cause rigor play in preventing recurring scrap on flight-critical components?

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