A more accurate assessment of circadian typology is achieved by asking persons to indicate their preferred times rather than comparing themselves with most people

The aim of the present work was to compare two circadian questionnaires: the Preference Scale (PS) and the reduced version of the Morningness-Eveningness Questionnaire (rMEQ). A sample of 849 (35.10% men) university students, 421 of whom were Spanish (27.55% men; mean age 21.07 + 2.31) and 428 Italian (42.52% men; mean age 23.26 + 3.01), were administered both questionnaires. Gender (higher morningness in women) and nationality (higher eveningness in Spaniards) differences were replicated with rMEQ but not with PS, in which an inverse association between nationality and circadian preference was observed (i.e. higher morningness in Spaniards). Taking into account that the formulation of the rMEQ items, with its specific times, makes the answers less influenced by socio-cultural bias, we conclude that rMEQ is preferable to PS when evaluating circadian preference in young adults.