Metric properties of the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-Participation) in persons with spinal cord injury living in Switzerland

Abstract

OBJECTIVE: To examine the metric properties of the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-Participation) in persons with spinal cord injury in Switzerland from a classical and item response theory perspective. DESIGN: Cross-sectional survey. SUBJECTS: Persons with spinal cord injury living in the Swiss community (n = 1,549). METHODS: Score distributions and internal consistency were evaluated using Classical Test Theory. The Restrictions and Satisfaction scales were subjected to Rasch analysis. Anchored analyses were performed to account appropriately for items with structural missing. RESULTS: Internal consistency was good for the Restrictions (α = 0.90) and Satisfaction scales (α = 0.90), but not for the Frequency scale (α = 0.65). Rasch analyses showed acceptable model fit for the Restrictions and Satisfaction scales after collapsing response categories of some items and merging some items into testlets. Differential item functioning was small. Anchoring allowed inclusion of the item work/education in the Restrictions scale and work/education and/or partner relationship in the Satisfaction scale. CONCLUSION: The Restrictions and Satisfaction scales of the USER-Participation showed satisfactory metric properties. The Frequency scale showed fewer optimal properties, but nonetheless provides important additional information regarding participation. Conversion tables were performed to transform USER-Participation raw scores into a 0-100 interval scale using Rasch-based ability estimates for use in epidemiological studies.