Study objectives: Previous research has reported mixed results in terms of sex differences in sleep quality. We conducted an analysis of measurement invariance of the Pittsburgh Sleep Quality Index (PSQI) between men and women to provide a necessary foundation for examining sleep differences.
Methods: The sample included 861 adults (mean age = 52.73 years, 47.85% male) from the 2012-2016 wave of the Midlife in the United States (MIDUS) Refresher Biomarker survey. We randomly divided the sample into two half samples for exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), respectively. We conducted EFA with a weighted least squares mean and variance adjusted (WLSMV) estimator and Geomin rotation to explore the underlying structure of the PSQI. We then employed multiple-group CFA with the WLSMV estimator and theta parameterization to examine measurement invariance between males and females.
Results: EFA suggested a two-factor structure of the PSQI, and the two-factor CFA model fit the data well. The finding that the two-factor PSQI model was invariant between males and females on configuration, factor loadings, thresholds for all but one measure, and residual variances for all but one measure provided evidence that the two-factor PSQI model was partially invariant between men and women. Females had higher means on latent factors, suggesting worse self-reports of sleep among women.
Conclusions: Overall, the measure of the PSQI assesses the same factors in a comparable way among men and women. Women reported worse sleep than men.
Keywords: Pittsburgh Sleep Quality Index; measurement invariance; midlife; sleep quality.
© 2019 American Academy of Sleep Medicine.