Chronotype: Validity and reliability of the MEQ

The chronotype is the behavioral manifestation of the endogenous circadian rhythm, reflecting an individual's tendency toward greater activity during a particular period of the day and toward earlier or later sleep schedules as a result of internal circadian cycles. Its most widely known and used self-report measure is the Morningness-Eveningness Questionnaire (MEQ). Although the MEQ has undergone numerous psychometric adaptations worldwide, relatively few studies have examined its psychometric properties, particularly its temporal stability. In Spanish-speaking Latin America, and particularly in Argentina, although many studies use the questionnaire, no study has reported its psychometric properties. The aim of this study is to provide evidence of the MEQ's factorial validity and reliability. 49 participants took part in the study, of whom 35 completed the test-retest assessment. Based on the scores of the 49 participants from the first assessment, parallel analysis suggested one principal component and one factor; a factor analysis with a one-factor model and the MINRES extraction method showed adequate model fit. Total score at the first and second assessments had a high correlation (r = .88), and agreement between first and second chronotype category was 88.6%, with a weighted kappa of κ = .78. Overall, this study is the first to provide evidence of the factorial validity and reliability of the MEQ in Spanish-speaking Latin America.