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Definitions of Accuracy and Precision

Accuracy

The accuracy of a measurement is how close a result comes to the true value. Determining the accuracy of a measurement usually requires calibration of the analytical method with a known standard.


Precision

Precision is the reproducibility of multiple measurements. It is usually described by the standard deviation, standard error, or confidence interval. A separate document defines these quantitative measures of precision.

Illustration of accuracy and precision
targets


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