The Sleep Acceptance Scale (SAS): Development, psychometric properties, and applications

OBJECTIVES: We developed and evaluated the psychometric properties of the Sleep Acceptance Scale (SAS), a tool designed to measure sleep acceptance via cognitive and emotional responses to sleep problems. METHOD: We designed a six-item scale, rated on a 7-point Likert scale, to capture the nuances of sleep acceptance. Data were collected from 1,350 participants, both with and without sleep problems. We employed an Exploratory Graph Analysis (EGA) and a Confirmatory Factor Analysis (CFA) to assess internal consistency, convergent validity, and measurement invariance over time and between groups. RESULTS: The EGA revealed a unidimensional structure for the SAS, which the CFA also confirmed. However, the root mean square error of approximation was marginally above the ideal threshold. The scale demonstrated high internal consistency (<math><mrow><msub><mi>ω</mi><mrow><mi>tot</mi></mrow></msub></mrow></math> = 0.91) and strong correlations with measures of insomnia severity, anxiety, depression, and willingness, supporting its convergent validity. Although the SAS maintained temporal stability over 14 days, it lacked configural invariance between good and bad sleepers, suggesting potential differences in how sleep acceptance manifested across these groups. CONCLUSIONS: The SAS effectively measures sleep acceptance, capturing important cognitive and emotional dimensions. It can be used to monitor progress in acceptance and commitment therapy and mindfulness-based interventions.