Composite and preferences Scales of Morningness: reliability and factor invariance in adult and university samples.

The creation and adaptation of scales or inventories assessing specific circadian typologies has been a predominant focus within the field of chronopsychology. The present study addressed the psychometric properties of two scales of morningness-eveningness: the Morningness Composite Scale (CS; Smith, Reilly, & Midkiff, 1989) and the Early/Late Preferences Scale (PS; Smith, Folkard, Schmieder, Parra, Spelten, & Almirall, 1993). Internal consistency and factor invariance of the CS and PS were analyzed in two samples: a group of 203 university students (age range = 19-30) and a group of 125 working adults (age range = 31-65). Results indicated satisfactory internal consistency for both full scales with each age group and confirmed the factor invariance across age for the two CS factors and one of the PS factors. A higher tendency in morningness on both scales was noted in the adult sample.