7. Conclusion

It is essential to associate an uncertainty with a measurement result: without it, the measured value is usually unusable. Measurement uncertainty is a quantification of the degree of doubt (or confidence) we have in the measurement result. It serves as a decision-making criterion when comparing results with one another or when comparing a result to a specification.

To estimate it, all stages of the measurement process must be taken into account. There are several approaches, which can be classified as intra- and interlaboratory comparisons.

Recent changes in the scope of the GUM mean that all of these approaches are covered by the GUM. They share two essential steps: defining the quantity to be measured (the measurand) as precisely as possible, and formulating a measurement model (physical/chemical or statistical).

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