Toward a Classification of Chronotype Questionnaires

Purpose: Chronotyping is a key methodology for assessing individual differences in human adaptation to the 24-h periodicity of geophysical and social environments. Throughout the 50-yr period of publications of chronotype questionnaires, there has been steady growth in their number and diversity. Therefore, it is becoming increasingly difficult to determine which questionnaires can be optimally applied to address a given research question. Consequently, this study aimed to develop a structured system for classifying and comparing chronotype questionnaires. Methods: A search in two bibliographic databases and 8 previously published reviews yielded 75 chronotype questionnaires. The properties of these questionnaires were defined and used for their classification and comparison. Results: Of 75 identified questionnaires, 60 and 15 were designed for only chronotype and chronotype and something else assessment, respectively. The set of 20 questionnaire and questionnaire scale properties was proposed. These properties were used to classify the questionnaires to allow the distinction of any of the questionnaires from other questionnaires. Conclusion: The proposed structured system of questionnaire classification can help in navigating between numerous published questionnaires. Using this system, an optimal instrument for a given research purpose can be chosen and properties of yet-unconstructed questionnaires and scales can be predicted. The Plain Language Summary: Chronotype refers to the behavior manifestations of individual differences in adaptation to the 24-h periodicity of geophysical and social environments. Chronotype questionnaires are permanently growing in number and diversity throughout the 50-yr period of their scientific publications. These questionnaires often have different aims, use different assessment methodologies, and, therefore, are not interchangeable. Given that some researchers would be confused about the different concepts behind these questionnaires, it is essential to determine what instrument to choose for a given research purpose. A system of questionnaire classification can help to navigate between numerous published questionnaires for choosing an optimal instrument for assessment of individual differences in a given study. Moreover, it can help to predict the properties of yet-unconstructed questionnaires. A system based on a set of 20 properties of questionnaires and questionnaire-scales was proposed. It might be used for choosing an optimal instrument for assessment of individual differences in the domain of chronobiology and sleep science and predicting properties of new questionnaires and new scales of published questionnaires. Keywords: morningness-eveningness, chronotyping, individual variation, self-assessment, classification