Frequently Asked Question
From need to CTQ
Voice-of-customer statements are often qualitative. Translate them into a measurable critical-to-quality requirement by identifying the user, use condition, direction of preference, target, tolerance, and verification method. Keep the original customer wording and the engineering interpretation linked so that a technical trade-off does not silently change the need.
Worked example
“Easy to open” becomes a force requirement such as 20–35 N at a defined temperature, orientation, cycle count, and hand position. The verification plan must identify the production-intent article, force gauge, sample size, acceptance rule, and treatment of outliers.
Engineering check
For Voice of Customer to Critical-to-Quality Requirements, maintain traceability from requirement to risk, design output, evidence, and approval. Record the configuration, acceptance criterion, test or analysis conditions, open actions, and residual risk. A method is not complete when the document is filled in; it is complete when the evidence supports the decision and affected controls are updated.
Engineering note
For Voice of Customer to Critical-to-Quality Requirements, state the intended use, input range, dominant mechanism, units, boundary conditions, acceptance criterion, and evidence owner. Use an independent balance, limiting case, repeat measurement, or sensitivity check to challenge the result. Document the configuration and uncertainty so another engineer can reproduce the reasoning and determine whether the result remains valid after a design, material, boundary, or process change.
Engineering note
For Voice of Customer to Critical-to-Quality Requirements, state the intended use, input range, dominant mechanism, units, boundary conditions, acceptance criterion, and evidence owner. Use an independent balance, limiting case, repeat measurement, or sensitivity check to challenge the result. Document the configuration and uncertainty so another engineer can reproduce the reasoning and determine whether the result remains valid after a design, material, boundary, or process change.