Psychometric validation of the seven-time dimensions scale: a measure of daily time experience quality for nurses’ mental health

Abstract

The Seven-Time Dimensions Scale (STDS) assesses daily life rhythms and perceived psychosocial resources, addressing the limitations of traditional symptom-focused tools and meeting the need for a comprehensive assessment for mental-health-related factors. However, as this scale has not been validated in Chinese nurses, the present study evaluates its application in this population. Convenience sampling was used to recruit 1,301 Chinese nurses. Reliability was verified using internal consistency coefficient and split-half reliability. The sample was randomly divided into two independent subsamples for exploratory (Group 1, n = 650) and confirmatory (Group 2, n = 651) factor analyses. To further assess the structural stability and verify the unidimensional structure of STDS, a bifactor confirmatory factor analysis (CFA) and an exploratory structural equation modeling (ESEM) were conducted. Additionally, multigroup confirmatory factor analyses (MG-CFA) were performed across demographic variables to test measurement invariance. Convergent and criterion-related validity were evaluated using Pearson correlations, and incremental variance beyond demographic covariates was assessed using hierarchical regression analyses. The item-total correlation coefficients ranged from 0.764 to 0.890 (p < 0.001), indicating good internal consistency (Cronbach’s α = 0.900; split-half reliability = 0.893). Exploratory factor analysis extracted a single factor accounting for 61.049% of the variance; CFA supported the unidimensional structure (χ²/df = 2.214, RMSEA = 0.043, CFI = 0.993, TLI = 0.990, SRMR = 0.016). A 1-factor ESEM on the confirmatory subsample cross-validated this structure (χ²/df = 2.214, CFI = 0.993, TLI = 0.990, RMSEA = 0.043, SRMR = 0.014), providing further evidence for the stability of the single-factor solution. The bifactor model demonstrated excellent fit (χ²/df = 1.800, CFI = 0.996, TLI = 0.989, RMSEA = 0.035, SRMR = 0.011). The hierarchical ω coefficient (ωh) was 0.896, and the covariation variance explained (ECV) was 0.953, indicating that the general factor explained over 95% of the covariation variance. The MG-CFA results supported full scalar invariance across demographic variables (except for sex and ethnicity) across the full scale (ΔCFI ≤ 0.003, ΔRMSEA ≤ 0.007), suggesting that STDS has strong structural stability across different nurse subgroups. Criterion-related validity analyses revealed that STDS scores were positively correlated with WHO-5, PSSS, and CD-RISC-10 (r = 0.650, 0.492, and 0.555, respectively; p < 0.001) and negatively correlated with the PSS (r = − 0.526, p < 0.001). Hierarchical regression analyses indicated that the scale explained significant incremental variance in the criterion variables beyond demographic covariates. STDS demonstrates acceptable reliability and validity as a preliminary measurement tool for assessing daily time experience quality associated with mental-health-related outcomes among Chinese nurses and can be used in future research and practice to develop mental health regulation strategies targeting this population.