Disentangling trait and developmental chronotype across the lifespan: An augmented regression-based approach to norms...

Chronotype manifests trait-like dispositions and age-related developmental shifts; yet the psychometrics of existing morningness-eveningness (ME) scales do not reflect the distinctness of these influences. Three issues contribute to this construct-measurement mismatch: assumed age-invariance of reliability and validity, uniform cutoffs across age/sex, and unwarranted conflation of trait and developmental ME. We aimed to exemplify solutions for these issues and deliver age-stratified psychometrics and augmented regression-based norms (RBN) that disentangle trait and developmental ME for the European Portuguese CSM.

Multi-cohort data from Portuguese residents/native speakers were pooled. Reliability (N = 2890; 12-94 years) and validity (n = 1880; 12-75 years) were examined overall and across five age groups. Hierarchical step-down regression selected predictors for the augmented RBN. Predictive performance was compared with conventional whole-sample norming on sleep timing and mental-health outcomes.

Age-stratified analyses showed adolescents and older adults diverged from overall reliability and validity patterns; nevertheless, indices were adequate. RBN included linear and quadratic age in adolescence and, in adulthood, an additional Age × Sex interaction. Augmented scores' disentangled trait and developmental components better predicted validity indicators and mental-health outcomes than conventionally normed scores. A public calculator returns ME z-scores, percentiles, and a 9-category chronotype classification for trait, developmental, and combined chronotype.

Augmented RBN for the CSM deliver trait, developmental, and combined ME scores and classifications that improve prediction and offer clinical utility for exploring vulnerabilities to psychological distress, sleep problems, and cognitive complaints. The approach may generalize to other ME scales.