title: Psychometric properties of Persian version of Composite Scale of Morningness.
abstract: BACKGROUND
  Morningness-eveningness preference is commonly measured by questionnaires such as the Composite Scale of Morningness (CSM). The purpose of this study is to assess the Persian translation of the CSM and explore its psychometric properties.
  
  
  METHODS
  Participants consisted of 288 students at the University of Bojnord, Iran. Of the participants selected, 47.6% were female, 52.4% were male, and all were aged between 18 and 24 (20.09±1.32). Participants were selected using the stratified random sampling method. The scale was translated into Persian using the parallel translation method. SPSS-22 and AMOS-22 were used for analyses.
  
  
  RESULTS
  Mean CSM scores were 31.43±6.32 in a range of 14-50. Internal reliability, as measured by Cronbach's α, was 0.790, which fits well with previous studies undertaken in many countries. The factor analysis revealed a two-factor structure based on parallel analysis: one factor was labeled as "morning affect" and the other as "self-assessment/activity planning." Also, the confirmatory factor analysis supported the two-factor model fit. Construct validity was also evaluated by the MEQ with the results showing that correlations were comparable to other studies (r=0.76). Results did not show any significant correlation between age (r=0.041; P=0.487) and the CSM scores. According to the results of the t-test, women and men were not significantly different in terms of the CSM scores (t=-0.264; P=0.792).
  
  
  CONCLUSIONS
  The Persian version of the CSM is freely available and can be adopted for behavioral research related to sleep and circadian function and also applied to other Persian-speaking populations.
authors.affiliation: Department of Psychology, Faculty of Humanities, University of Bojnord, Bojnord, Iran. Electronic address: Tayebe.Rahimi@yahoo.com.
authors.forename: Tayebe
authors.initials: T
authors.lastname: Rahimi Pordanjani
authors.affiliation: Department of Psychology, Faculty of Humanities, University of Bojnord, Bojnord, Iran.
authors.forename: Ali Mohamadzade
authors.initials: AM
authors.lastname: Ebrahimi
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007492:Iran; D008297:Male; D011594:Psychometrics / Q000295:instrumentation*; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult
keywords: Circadian rhythm; Morningness–eveningness; Persian version of the Composite Scale of Morningness