Psychometric evaluation of the early/late preferences scale

Area of Science:

• Chronobiology
• Psychometrics

Background:

• Morningness-eveningness chronotypes influence daily functioning.
• Accurate measurement of chronotype is essential for research and clinical applications.

Purpose of the Study:

• To evaluate the psychometric properties of the Early/Late Preferences Scale (PS).
• To compare the PS with the established Composite Morningness Scale (CS).

Main Methods:

• 670 undergraduate students (aged 16-37) completed the PS and CS.
• Psychometric analyses included inter-item correlations, factor analysis, internal consistency, and test-retest reliability.
• Convergent validity was assessed through correlations with self-rated alertness and other morning-evening orientation indices.

Main Results:

• Both scales showed good internal consistency (PS=0.86, CS=0.90) and test-retest reliability (PS=0.92, CS=0.89).
• Factor analysis supported a single-factor solution for both scales.
• Evidence of validity was found for both scales, with comparable performance.

Conclusions:

• The Early/Late Preferences Scale (PS) exhibits psychometric quality comparable to the Composite Morningness Scale (CS).
• The PS offers a simpler format and less cultural specificity, making it a potentially preferable measure for chronotype assessment.