Assessment of fatigue among working people: a comparison of six questionnaires.

AIMS To compare the psychometric qualities of six fatigue questionnaires in a sample of working persons. METHODS Internal consistency and test-retest reliability, content validity, convergent validity, and the dimensionality of the fatigue instruments were explored. RESULTS All scales had a satisfactory internal consistency. Furthermore, based on factor analyses and Mokken scale analyses, all scales were unidimensional and appeared to measure an identical construct. The Fatigue Assessment Scale (FAS) had the highest factor loading on the one factor solution obtained in a factor analysis of the total scores of all scales. CONCLUSIONS All the questionnaires were unidimensional and had good reliability and validity. The FAS was the most promising fatigue measure.