Accuracy and Precision

Accuracy refers to the closeness between measurements (observations) and their expectations ("true" values). The farther a measurement is from its expected value, the less accurate it is.

Precision pertains to the closeness to one another of a set of repeated observations of a random variable. Thus, if such observations are closely clustered together, then these observations are considered to have been obtained with high precision.

• Accuracy versus Precision
• Repeatability
• An Example

The example and the previous definitions are presented here to clarify some key terms necessary for communicating, integrating, or analyzing any set of measurements. A full understanding of these concepts requires a strong background in statistics.