A Note on “Accuracy” and “Precision”

The terms accuracy and precision are consistently differentiated in the literature of engineering and the “hard” sciences. Precision shares a common core of meaning with reliability as used by behavioral scientists. Accuracy and validity have a similar semantic overlap. A review of the literature in educational and psychological measurement reveals an interchangeable usage of accuracy and precision in defining reliability, To help beginning students distinguish between validity and reliability, this paper advocates the use of precision, rather than accuracy, in describing reliability.