Precision, accuracy and accuracy of measurement
Precision, accuracy and accuracy of measurement are the basic concepts of measurement (see figure 1).
I. precision
Precision of measurement refers to the degree of consistency between the measured values after repeated measurement of the measured values under the same conditions. From the perspective of measurement error, precision reflects the random error of the measured value. High precision, not necessarily accuracy (see below). In other words, the random error of the measured value is small, not necessarily the systematic error is small.
II. accuracy
Correctness of measurement is the degree to which the measured value is considered to be close to the "true value". From the perspective of measurement error, the accuracy reflects the systematic error of the measured value. High accuracy, not necessarily high precision. In other words, the systematic error of the measured value is small, not necessarily the random error is small.
III. precision
Accuracy of measurement, also known as accuracy of measurement, refers to the degree of consistency between measured values and the degree of proximity to their "true value", which is a comprehensive concept of precision and accuracy. From the perspective of measurement error, accuracy (accuracy) is a comprehensive reflection of the random error and systematic error of the measured value.
Figure 1 is a schematic of the accuracy and accuracy of the measurement precision 1.
Set the center O of the circle in the figure as the measured "truth value", and the black point as the measured value, then
Figure (a) : high accuracy and low precision;
Figure (b) : high precision and poor accuracy;
Figure (c) : higher accuracy (accuracy), i.e. higher precision and accuracy.
Generally speaking, the precision of measurement or measuring instrument is usually referred to as accuracy (accuracy). , not precision. In other words, "precision" has actually become the customary shorthand for "accuracy." As for the claim that precision is short for precision, if only for precision, it is ok; But when considered in all, precision, accuracy, and accuracy, it would be more appropriate to refer to the abbreviation or the original meaning of precision. Because, in the actual work, the evaluation of the measurement result, multi-system comprehensive, only in certain specific occasions to precision and accuracy alone considered. So why not simplify (if "simplify") a common term rather than a less common one? Moreover, in most metrological fields and metrologists, the term "precision" is used to mean "accuracy" or "accuracy".
By the way, the word "precision" used in this book means "precision" (accuracy), a composite concept of precision and accuracy.