Psychometric properties of the German version of the Composite Scale of Morningness

Abstract

The Composite Scale of Morningness is widely used and was translated into several languages. The aim of this study was to validate the German CSM scale and to present first results based on a sample of pupils and university students. The sample consisted of a total of 3745 persons (63.8% females). Mean age was 15.9 ± 4.0 (SD) years with a range from nine to 52 years. Cronbach's α coefficient was 0.84 and the inter-item correlations were all positive with an average value of 0.296 and a range between 0.112 and 0.764. Based on the eigenvalue-greater-than-one criterion a three factor solution was provided. After rotation, eigenvalues were 3.40 (26.2%), 2.36 (18.2%), and 1.61 (12.4%). As an external validation, I used the German translation of the morningness – eveningness questionnaire (MEQ). The correlation was high (r = 0.89). To investigate differences in morningness/eveningness in pupils and students a sub-sample was used (N = 3577; mean age 15.4 ± 3.0, range 10 – 22). Using age classes as factors revealed significant differences [one-way ANOVA: F(12, 3564) = 31.352; P < 0.001]; both in males [one-way ANOVA: F(12, 1294) = 18.188; P < 0.001] and in females [one-way ANOVA: F(12, 2257) = 15.047; P < 0.001]. A correlational analysis using age as a continuous variable showed similar effects (r = −0.252; P < 0.001). However, the correlation coefficient was higher in males (r = −0.328; P < 0.001) than in females (r = −0.221; P < 0.001). A pairwise comparison from a post hoc Bonferroni found that CSM scores differed significantly between the age of 12 and 13. At first, there were no significant gender differences in CSM scores, but after applying a general linear model (GLM) using age and gender as factors there was a significant influence of both age [F(12, 3551) = 33.5; P < 0.001] and gender [F(1, 3551) = 5.7; P = 0.017], and, furthermore, a significant interaction [age ^⋆ gender interaction: F(12, 3551) = 2.3; P = 0.006)].

Keywords:

• Age
• circadian rhythms
• chronotype
• gender
• German Composite Scale of Morningness
• morningness – eveningness

Acknowledgements

I am grateful to the pupils, their parents and their respective teachers. The cooperation of the principals of the schools is highly appreciated. I was supported by the Bundesministerium für Bildung und Forschung (BMBF) JP CR and by a grant from the University of Education. Many thanks go to Gabriele Topaltzis for inputting the data.