Psychometrics of the observational scales of the Utrecht Scale for Evaluation of Rehabilitation (USER): Content and structural validity, internal consistency and reliability

Abstract

Introduction: Establish content and structural validity, internal consistency, inter-rater reliability, and measurement error of the physical and cognitive scales of the Utrecht Scale for Evaluation clinical Rehabilitation (USER) in geriatric rehabilitation. Material and methods: First, an expert consensus-meeting (N=7) was organised for content validity wherein scale content validity index (CVI) was measured. Second, in a sample of geriatric rehabilitation patient structural validity (N=616) was assessed by confirmatory factor analyses for exploring unidimensionality. Cut-off criteria were: Root Mean Square Error of Approximation (RMSEA) ≤0.08; Comparative Fit Index (CFI) and Tucker Lewis Index (TLI) ≥0.95. Local independence (residual correlation<0.20) and monotonicity (Hi-coefficient ≥0.30 and Hs-coefficient ≥0.50) were also calculated. Cronbach alphas were calculated for internal consistency. Alpha's > 0.7 was considered adequate.Third, two nurses independently administered the USER to 37 patients. Intraclass-correlation coefficients (ICC) were calculated for inter-rater reliability (IRR), standard error of measurement (SEM) and Smallest Detectable Change (SDC). Results: The CVI for physical functioning was moderate (0.73) and excellent for cognitive functioning (0.97). Structural validity physical scale was acceptable (CFI;0.95, TLI;0.93, RMSEA;0.07, ECV;0.78, OmegaH;0.87; Monotonicity;(Hi;0.52-0.75 and Hs;0.63)). Cognitive scale was good (CFI;0.98, TLI;0.96, RMSEA;0.05, ECV;0.66 and OmegaH;0.90. Monotonicity;(Hi;0.30 –0.70 and Hs;0.61)). Cronbach's alpha were high: physical scale;0.92 and cognitive scale;0.94. Reliability physical scale ICC;0.94, SEM;5 and SDC;14 and cognitive scale ICC;0.88, SEM;5 and SDC;13. Conclusion: The observational scales of the USER have shown sufficient content and structural validity, internal consistency, and interrater reliability for measuring physical and cognitive function in geriatric rehabilitation. Trial registration: N/A