Repeatability

Repeatability or test–retest reliability[1] is the closeness of the agreement between the results of successive measurements of the same measure, when carried out under the same conditions of measurement. [2] In other words, the measurements are taken by a single person or instrument on the same item, under the same conditions, and in a short period of time. A less-than-perfect test–retest reliability causes test–retest variability. Such variability can be caused by, for example, intra-individual variability and inter-observer variability. A measurement may be said to be repeatable when this variation is smaller than a predetermined acceptance criterion.

Test–retest variability is practically used, for example, in medical monitoring of conditions. In these situations, there is often a predetermined "critical difference", and for differences in monitored values that are smaller than this critical difference, the possibility of variability as a sole cause of the difference may be considered in addition to, for example, changes in diseases or treatments.[3]

  1. ^ Types of Reliability Archived 2018-06-06 at the Wayback Machine The Research Methods Knowledge Base. Last Revised: 20 October 2006
  2. ^ JCGM 100:2008. Evaluation of measurement data – Guide to the expression of uncertainty in measurement (PDF), Joint Committee for Guides in Metrology, 2008, archived (PDF) from the original on 2009-10-01, retrieved 2018-04-11
  3. ^ Fraser, C. G.; Fogarty, Y. (1989). "Interpreting laboratory results". BMJ (Clinical Research Ed.). 298 (6689): 1659–1660. doi:10.1136/bmj.298.6689.1659. PMC 1836738. PMID 2503170.