Precision

Precision can refer to a number of different concepts. Diagnostic precision may refer to a test‘s positive predictive value or its reproducibility when repeated on the same sample (i.e. variation in results due to random error, often expressed as a coefficient of variation). More generally in statistics, precision refers to the tightness of distribution (degree of spread around the average value) of a quantity, e.g. one measured in a population survey. Formally, precision is defined as the reciprocal of the variance of this distribution.