Can you feel the rhythm? A short questionnaire to describe two dimensions of chronotype

Abstract

The article presents the short questionnaire aimed at describing two dimensions of chronotype: subjective phase, i.e. morning–evening preference (M–E scale, 8 items) and subjective amplitude, i.e. distinctness of the diurnal rhythm of activation (DI scale, 6 items). The study comprised 1374 subjects (13–91 years old, 769 women, 605 men). There was no gender difference in morning–evening orientation, but women scored significantly higher on the distinctness scale ( p < .0001). Analyses were conducted in four homogenous sub-groups extracted from the investigated population: schoolchildren, university students, medical doctors, and pensioners. Younger subjects revealed significantly later subjective phase; oldest subjects showed smaller subjective amplitude. The Chronotype Questionnaire is a tool of satisfactory accuracy. It shows good enough internal reliability – significant item-total correlations in both scales and acceptable Cronbach’s alpha for M–E scale (0.66–0.84, depending on age group). DI scale showed to be weaker (Cronbach’s alpha 0.51–0.72). The questionnaire seems to be less reliable in young people at their adolescence than in older subjects. High reproducibility of the results in a two-week test–retest ( p < .001) was proved in the student group. Moreover, there was a significant correlation between self-assessments of the subjective phase investigated in a sub-group of 28 subjects in the 7-year interval.