Measurement, Test & Control Equipment worked example

Component Tolerance Stack Risk with severity score of 18 1-10: a worked example

What does the result look like when severity score reaches 18 1-10? The full calculation is worked below with real intermediate numbers. Use when evaluating tolerance stack risk in precision assemblies, ranking measurement system design risks, or prioritizing design changes during FMEA reviews for test fixtures and instrument assemblies.

The inputs for this scenario

  • Severity score: 18 1-10 (raised for this scenario; the documented default is 7)
  • Occurrence score: 4 1-10 (unchanged)
  • Detection score: 5 1-10 (unchanged)

Working through the calculation

  • Applying the documented formula (Risk priority number (RPN) = severity score x occurrence score x detection score) to the inputs above produces each figure below.
  • At this operating point the engine returns 9.85 score for risk priority number (rpn), the number this scenario is built around.
  • At this operating point the engine returns 18 score for severity score.
  • At this operating point the engine returns 4 score for occurrence score.
  • At this operating point the engine returns 5 score for detection score.

How this compares with the baseline

  • Against the tool's baseline example, where severity score sits at 7 1-10 and the headline result is 5.45 score, this scenario comes in 80.73% above the baseline at 9.85 score.
  • A figure at this level is achievable when severity score is genuinely sustained, not just peaked for a shift. RPN is ordinal, not a probability, and equal RPNs can hide very different risk profiles, so always review the underlying severity score independently.

Results at a glance

  • Risk priority number (RPN): 9.85 score (headline result)
  • Severity score: 18 score
  • Occurrence score: 4 score
  • Detection score: 5 score

Run it with your numbers

  • Every input above is editable in the live Component Tolerance Stack Risk calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.