Reliability

The psychometric properties of measures are presented in terms of their reliability and validity. Reliability relates to the ability of a measure to produce consistent test scores. There are four general types of reliability: interrater, test-retest, alternate forms, and internal consistency. Interrater reliability refers to consistency across raters or evaluators; test-retest reliability refers to the consistency of scores on a test administered twice to the same individual; alternate forms reliability relates to the stability of scores on two parallel forms (e.g., A and B) of a test; and measures of internal consistency are investi gated to determine levels of consistency among items in the same test. For more information, see DeVon, Block, and Moyle-Wright (2007).