Psychometric and Structural Validity of the Pittsburgh Sleep Quality Index among Filipino Domestic Workers

Objectives: Evaluate the psychometric properties and structural validity of the Filipino version of the Pittsburgh Sleep Quality Index (PSQI) among Filipino domestic workers (FDWs). Methods: In Study 1, 131 FDWs completed PSQI and other scales, along with 10-day actigraphic assessment with accompanying electronic daily sleep dairy. A subsample of 61 participants completed follow-up assessment after 10 days. In Study 2, 1363 FDWs were recruited and randomized into two halves. Exploratory factor analysis (EFA) and Confirmatory factor analysis (CFA) were used in the two halves, respectively. Results: In Study 1, the Cronbach’s alpha of the PSQI was 0.63 at baseline and 0.67 at follow-up. Test-retest reliability for the PSQI global score based on intraclass correlation was 0.63. Convergent validity was supported by the significant associations between the PSQI global score, PSQI components scores, sleep patterns from the daily sleep diary, and measures of depression, anxiety, and rumination. Small correlations between the PSQI global score and measures of daytime sleepiness, social support, and self-reported height, supported discriminant validity. In Study 2, EFA yielded two PSQI factors with acceptable factor loadings. CFA established that this two-factor model, comprised of perceived sleep quality and sleep efficiency, evidenced better model fit than alternative models tested. The Cronbach’s alpha of two factors was 0.70 and 0.81, respectively. Conclusions: The PSQI demonstrated good internal consistency of two factors, and good convergent, and divergent validity. Results can be referenced in future studies to measure and screen sleep dysfunction among clinical and non-clinical populations in the Philippines.