An evaluation of the Circadian Type Questionnaire

• Published in: Ergonomics Vol. 38; no. 2; p. 347
• Main Author: Greenwood, Kenneth M
• Format: Journal Article
• Language: English
• Published: England 01.02.1995
• Subjects: Circadian rhythms; Morningness-eveningness; Shiftwork; Chronotype; Chronobiology; Work schedule tolerance
• ISSN: 1366-5847
• DOI: 10.1080/00140139508925109

This study evaluates the psychometric properties and assesses the test-retest reliability and longer-term stability of scores on the Circadian Type Questionnaire (CTQ) of Folkard et al. (1979) in a sample of 445 students. The scales were found to lack internal consistency and the factor structure originally proposed was not replicated. Cultural variation in CTQ scores was suggested. Test-retest reliability, over three months in a subgroup of 36, was poor for the V and M scales. Longer-term stability, over nine months in a subgroup of 36 who were exposed to shiftwork, was better but significant decreases were found in rigidity of sleeping habits (R ) and morningness (M) scores. A factor analysis suggested that the scales should be constructed differently; however, the properties of such scales were still not optimal. The CTQ has psychometric flaws and needs to be improved before it could be expected to reliably function as a predictive test of adaptation to shiftwork.