Test-retest reliability and measurement error of the Danish WHO-5 Well-being Index in outpatients with epilepsy

Background The generic questionnaire WHO-5 Well-being Index (WHO-5), which measures the construct of mental well-being has been widely used in several populations across countries. The questionnaire has demonstrated sufficient psychometric properties; however, the test- retest reliability of the WHO-5 scale has yet to be determined. The aim of this study was to evaluate the test-retest reliability and measurement error of the Danish WHO-5 Well-being Index for outpatients with epilepsy. A further aim was to evaluate whether the method of administration (web, paper, or a mixture of the two modalities) influenced the results.