Psychometric properties of the reduced Horne and Ostberg questionnaire

The purpose of the present study was to begin the process of establishing psychometric soundness of the reduced Horne and Ostberg questionnaire (rH&O, Adan & Almirall (1991). Horne and Ostberg morningness-eveningness questionnaire: a reduced scale. Personality and Individual Differences, 12, 241-253.). In the first stage of the study a total of 1882 students from the University of North Dakota were administered the original H&O questionnaire (Horne & Ostberg (1976). A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. International Journal of Chronobiology, 4, 97-110. 19-items). Five items that constitute the rH&O were extracted from the original 19 items questionnaire and the relationship between the total scores of both questionnaires, and between the circadian types determined by H&O and rH&O was measured by computing appropriate correlation coefficients. In the second stage of the study the original H&O questionnaire and the rH&O (5-items) questionnaire were administered to another group of college students (n = 150). The results from both parts of the present study indicate that the rH&O has adequate inter-item correlations as well as high coefficient alpha. Furthermore, the rH&O questionnaire is sufficiently sensitive with respect to the results of the original H&O questionnaire and it reliably classifies research participants across the morningness-eveningness dimension. Working with the rH&O could save both the researchers and the participants time and effort, especially if large samples of populations are to be studied. Conclusions and limitations are discussed as well as the directions for future studies. (C) 2000 Elsevier Science Ltd. All rights reserved.