Pain measurement

In medicine, pain measurement is the use of "scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies."

Numeric rating scale
Pain may be quantified on a pain numeric rating scale (NRS) that ranges from 0-10 points (0 means no pain); however, the accuracy of such as scale (using a cut point of 4 or more) for predicting pain that interferes with functioning is:
 * sensitivity 64%
 * specificity 83%

Visual analog scale
Visual analog scales (VAS) have been used to measure pain. An observational study concluded "the minimum clinically significant change in patient pain severity measured with a 100-mm visual analog scale was 13 mm."