Psychometric properties of the Persian version of the reduced Morningness-Eveningness Questionnaire: Further evidence

Circadian types are related to many physiological, cognitive, and behavioral variables and, therefore, a need for a questionnaire in Farsi language to assess those preferences has emerged. The present study aimed at exploring psychometric properties of the reduced version of the Persian Morningness-Eveningness Questionnaire (rMEQ). Participants were 268 students recruited from two different universities. Three questionnaires were used to investigate the additional validity data of the Persian version of the rMEQ: Beck Depression Inventory (BDI-II), Oxford Happiness Questionnaire (OHQ), and General Health Questionnaire (GHQ-12). The correlations between the rMEQ and the three other questionnaires were -0.45, 0.48, -0.41, respectively. Moreover, the factor analysis of the rMEQ resulted in a single-factor solution and the Cronbach's was 0.71. In sum, the Persian rMEQ seemed to be a reliable and valid instrument to differentiate circadian types. We suggest that future studies focus on test-retest reliability of the rMEQ and an analysis of its unidimensionality with other methods like Item-Response Theory (IRT).