Psychometric properties of the Turkish version of the Composite Scale of Morningness.

The Composite Scale of Morningness is widely used and translated into several languages. The aim of the study was to present psychometric properties of Turkish version of CSM based on a sample of high school and university students. A total of 543 high school and 650 university students have participated in to the study. The internal consistency coefficient was found to be .73 (high school) and .80 (university). The test-retest reliability of the scale was .89 in high school sample and .84 in university sample. The mean CMS scores did not differ by gender in both samples. Exploratory and confirmatory factor analysis revealed that the scale is valid. As an external validation, morningness was associated with MEQ scores, sleep length, mid-point of sleep, rising and retiring time. The data obtained in the study suggested that the Turkish version of the CSM is a reliable and valid instrument to assess circadian preference in both high school and university samples.