Validation of the SIC (Single Item Chronotyping) against 11 scales of three questionnaires

Abstract

In 2021, the Single-Item Chronotyping (SIC) was introduced in this journal. This is a new method to self-assess diurnal types by using 6 simple charts illustrating morning, afternoon, and evening levels of alertness of 6 chronotypes (lethargic, vigilant, evening, morning, afternoon, and napping). Its output is the names of chronotypes rather than clock time or scale score of any of other chronotype questionnaires. Consequently, the SIC cannot be validated by applying the conventional way of evaluating validity of a questionnaire against the already established questionnaires (e.g., by the simple estimation of correlation coefficients between outputs of the questionnaires). Therefore, we proposed here a method of validation of the SIC against the scales of already established multi-item chronotype questionnaires which output are scores on separate morning, afternoon, and evening scales. We suggested that, if three-score (morning, afternoon, and evening) diurnal curve can be constructed for each of the SIC chronotypes, we can test the hypothesis that the SIC charts predicted these three-score curves. Scores on scales of three questionnaires were obtained from 4940 survey participants and used to construct and statistically evaluate such curves. Results supported the hypothesis that the obtained curves were predicted by the SIC charts.