Morningness–eveningness across two student generations: would two decades make a difference?

The majority of morningness–eveningness questionnaires measure differences in preferred time of various daily activities. This study measured differences in actual habits during a 24-h period by means of the Student Morningness–Eveningness Questionnaire (SMEQ) developed by [ verko, B., Vida ek, S., & Kaliterna, L.J. (1979)]. Osobine li nosti I svakodnevne navike ivota [Personality characteristics and daily habits]. Revija za psihologiju, 9, 49–58.). Data on actual daily habits were collected in the 1998 student generation (n=189) and compared to those of the generation examined in 1977 (n=128) that were published by verko et al. (1979). The aims of the study were to examine psychometric properties of the SMEQ as well as to see if two student generations, 21 years apart, differed in their results on the questionnaire. Cronbach alpha coefficients were identical for both generations (0.77). Discrimination value of the items has not changed significantly, except on four questions. The results on the SMEQ were distributed normally in both generations and no significant differences were found between the mean values of the two groups. The results of the study testify to a high stability of the SMEQ as well as to stability of the morningness–eveningness dimension across two generations.