The Composite Scale of Morningness: further psychometric properties and temporal stability

Object - To assess the temporal stability of the French version of the Comp osite Scale of Morningness (CSM), and to replicate our previous findings in an independent sample in order to confirm the good internal properties of this instrument. Method - Sixty nursing students (11 males and 49 females) filled out the Co mposite Scale of Morningness on two occasions over a 13-month period. Results - The scale's reliability is high: Cronbach's alpha = 0.874 in male s and 0.904 in females. The CSM total scores are normally distributed and i ndependent of gender. They do not differ between occasions, and are highly correlated: r = + 0.885 in males and r = + 0.930 in females. Conclusion - The French version of the CSM is stable over time and psychome trically reliable. These are the characteristics of a personality trait. Fu rther studies should explore its personality, biological and genetic correl ates. (C) 2000 Editions scientifiques et medicales Elsevier SAS.