Comparing three morningness scales: Age and gender effects, structure and cut-off criteria

Abstract

Objective To add to the validity of the French version of the Composite Scale of Morningness (CSM) by comparing its structure with that of the Morningness–Eveningness Questionnaire (MEQ), the most widely used scale to measure circadian typology. Second, to compare the cut-off criteria used to transform the continuous scores into categorical chronotypes. Third, to further test the effects of age and gender on morningness scores. The rMEQ, a shortened version of the MEQ, is also considered. Methods Four hundred and fifty-six students served as volunteer subjects and filled the CSM and the MEQ. Results There was no effect of gender, and the CSM and MEQ scores correlated above +0.90 in both genders. Regarding age, morningness was stable before age 35 and increased afterwards. We replicated the three-factor structure of the CSM previously reported in five different cultures. The MEQ is longer and counted a fourth factor while the first three factors were quite identical to those extracted from the CSM. This comparative study emphasizes the recurrent problem of cut-off scores: the available values for both instruments result in a very poor concordance of chronotypes. Conclusions Belonging to the evening-type is regarded as a risk factor for sleep disorders and its positive predictive value should be correctly assessed. Hence, normative scores standardized in such a way they reflect the effects of age, gender and culture are needed for the total score and the factor scores. To this extent, T-scores (with a mean of 50 and standard deviation of 10) would be suitable, and normative tables for French subjects ( N = 1598) are given as supplemental data.