Disentangling trait and developmental chronotype across the lifespan: An augmented regression-based approach to norms for morningness-eveningness scales.
Buekenhout I, Gomes A, Leitão J • Sleep medicine • 2026
Augmented regression-based norms for the European Portuguese Composite Scale of Morningness that disentangle trait and developmental chronotype components better predicted sleep timing, mental-health outcomes, and cognitive complaints than conventionally normed scores.
Key Findings
Results
Adolescents and older adults diverged from overall reliability and validity patterns of the CSM, though indices remained adequate across all age groups.
Reliability was examined across five age groups in a sample of N=2890 participants aged 12-94 years
Validity was examined in n=1880 participants aged 12-75 years
Age-stratified analyses revealed that adolescents and older adults showed divergent patterns compared to the overall sample
Despite divergence, reliability and validity indices were described as 'adequate' across all age strata
Results
Regression-based norms for the CSM included linear and quadratic age terms in adolescence, and an additional Age × Sex interaction term in adulthood.
Hierarchical step-down regression was used to select predictors for the augmented regression-based norms (RBN)
In adolescence, both linear and quadratic age components were retained as predictors
In adulthood, an Age × Sex interaction was identified as an additional significant predictor
This modeling approach reflects both the curvilinear developmental trajectory of chronotype across adolescence and sex-differentiated aging patterns in adulthood
Results
Augmented regression-based normed scores that disentangle trait and developmental morningness-eveningness components better predicted validity indicators and mental-health outcomes than conventionally normed scores.
Predictive performance was compared between augmented RBN and conventional whole-sample norming
Outcomes assessed included sleep timing, mental-health outcomes, and cognitive complaints
The augmented scores separately estimated trait and developmental ME components
Conventionally normed scores, which conflate trait and developmental ME, showed inferior predictive performance relative to the augmented approach
Results
A publicly available calculator was developed that returns ME z-scores, percentiles, and a 9-category chronotype classification for trait, developmental, and combined chronotype.
The calculator outputs three types of scores: trait chronotype, developmental chronotype, and combined chronotype
Classification uses a 9-category system
Outputs include z-scores and percentiles in addition to categorical classifications
The tool is intended to offer clinical utility for exploring vulnerabilities to psychological distress, sleep problems, and cognitive complaints
Background
The study identified a construct-measurement mismatch in existing morningness-eveningness scales arising from three psychometric issues.
The three issues identified were: assumed age-invariance of reliability and validity, uniform cutoffs applied across age and sex groups, and unwarranted conflation of trait and developmental ME
Multi-cohort data from Portuguese residents and native speakers were pooled for the analyses
The sample spanned a wide age range of 12-94 years
The authors argue these issues affect the psychometric validity of existing ME scales broadly, and that the approach 'may generalize to other ME scales'
Conclusions
The augmented regression-based norms offer clinical utility for exploring vulnerabilities to psychological distress, sleep problems, and cognitive complaints.
Mental health and cognitive complaint outcomes were included as validity indicators in the norming study
Disentangling trait from developmental chronotype was posited to improve clinically relevant prediction
The authors describe the augmented scores as having 'clinical utility for exploring vulnerabilities to psychological distress, sleep problems, and cognitive complaints'
The approach was demonstrated specifically for the European Portuguese version of the Composite Scale of Morningness (CSM)
What This Means
This research suggests that common questionnaires used to measure whether people are 'morning types' or 'evening types' (chronotype) have a fundamental measurement problem: they treat chronotype as if it were a single, stable trait, when in reality it has two distinct components. One component reflects a person's stable, inborn tendency toward morningness or eveningness (trait chronotype), while the other reflects the well-known developmental shifts in sleep timing that occur across the lifespan — such as the tendency for teenagers to become more evening-oriented and for older adults to shift back toward mornings. By blending these two components together, conventional scoring methods obscure clinically meaningful information.
To address this, the researchers developed improved scoring norms for a widely used chronotype questionnaire (the Composite Scale of Morningness, European Portuguese version) using data from nearly 3,000 participants aged 12 to 94. Their statistical approach — called augmented regression-based norming — separates the age-related developmental shift in chronotype from a person's underlying trait tendency, and also accounts for the fact that men and women age differently with respect to chronotype. When tested against outcomes like sleep timing, mental health symptoms, and cognitive complaints, these disentangled scores outperformed conventional scoring methods in predictive accuracy.
This research suggests that knowing both a person's trait chronotype (how morning- or evening-oriented they are relative to others their age) and their developmental chronotype (how their timing compares to the overall population lifespan trend) provides richer, more clinically useful information. A free online calculator was created to generate these scores. The authors propose that this approach could be applied to other chronotype questionnaires beyond the one studied here, potentially improving how sleep researchers and clinicians assess and interpret chronotype across different age groups and sexes.
Buekenhout I, Gomes A, Leitão J. (2026). Disentangling trait and developmental chronotype across the lifespan: An augmented regression-based approach to norms for morningness-eveningness scales.. Sleep medicine. https://doi.org/10.1016/j.sleep.2026.108768