2. Measurement Process Characterization

2.5.	Uncertainty analysis

Uncertainty measures 'goodness' of a test result

This section discusses the uncertainty of measurement results. Uncertainty is a measure of the 'goodness' of a result. Without such a measure, it is impossible to judge the fitness of the value as a basis for making decisions relating to health, safety, commerce or scientific excellence.

Contents

1. What are the issues for uncertainty analysis?
2. Approach to uncertainty analysis
   1. Steps

3. Type A evaluations
   1. Type A evaluations of random error
      1. Time-dependent components
      2. Measurement configurations
   2. Type A evaluations of material inhomogeneities
      1. Data collection and analysis
   3. Type A evaluations of bias
      1. Treatment of inconsistent bias
      2. Treatment of consistent bias
      3. Treatment of bias with sparse data

4. Type B evaluations
   1. Assumed distributions

5. Propagation of error considerations
   1. Functions of a single variable
   2. Functions of two variables
   3. Functions of several variables

6. Error budgets and sensitivity coefficients
   1. Sensitivity coefficients for measurements on the test item
   2. Sensitivity coefficients for measurements on a check standard
   3. Sensitivity coefficients for measurements with a 2-level design
   4. Sensitivity coefficients for measurements with a 3-level design
   5. Example of error budget

7. Standard and expanded uncertainties
   1. Degrees of freedom

8. Treatment of uncorrected bias
   1. Computation of revised uncertainty