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2. Measurement Process Characterization
2.4. Gauge R & R studies


Analysis of bias

Definition of bias The terms 'bias' and 'systematic error' have the same meaning in this handbook. Bias is defined (VIM) as the difference between the measurement result and its unknown 'true value'. It can often be estimated and/or eliminated by calibration to a reference standard.
Potential problem Calibration relates output to 'true value' in an ideal environment. However, it may not assure that the gauge reacts properly in its working environment. Temperature, humidity, operator, wear, and other factors can introduce bias into the measurements. There is no single method for dealing with this problem, but the gauge study is intended to uncover biases in the measurement process.
Sources of bias Sources of bias that are discussed in this Handbook include:
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