01 · Purpose
Why and when to use it
Use it before interpreting a baseline when measurement error could conceal or imitate meaningful process differences.
Who takes part?
The measurement owner works with people who understand the process and the recorded data. Statistical or measurement-system decisions should involve someone able to check the assumptions and study design.
02 · Application
How to apply it
Start with an agreed measurement purpose, explicit units and trustworthy observations. Identify missing cases and assumptions before calculating.
- Define the characteristic, decision and required discrimination.
- Check the method, resolution and reference traceability.
- Choose a study appropriate to continuous measurements or categorical decisions.
- Include relevant operators, parts, repeats and conditions.
- Investigate error components, improve the method and confirm performance before relying on it.
03 · Example
A worked measurement example
Original fictional teaching example. Small datasets illustrate the method; they are not proposed as sufficient study sizes. Supplied parameters are assumptions, not estimates from a real process.
| Observed concern | Study direction |
|---|---|
| Different inspectors classify the same package differently | Attribute agreement study against an established reference |
| Repeated weight readings vary | Repeatability and multi-operator Gage R&R |
| Bias grows with package weight | Linearity study across the operating range |
04 · Interpretation
What the result tells you
Measurement error is part of the observed variation. Reliable readings at one reference point do not establish reliability across operators and the full operating range.
Completion check: Evidence about measurement suitability, with limitations and actions recorded.
05 · Judgement
Mistakes and limitations
Do not apply a universal pass percentage without considering the decision and consequences. Calibration alone does not evaluate the entire working measurement system.
07 · Reading
Sources and further reading
The tool list follows the accepted LeanTrainingLab overview and its reference to Six Sigma+Lean Toolset, second edition (Lunau, editor; Springer, 2013). The book chapters were not available for direct review during this build. Explanations, examples and worksheets are original teaching material. Further reading supplies professional background; local conventions are stated explicitly.