An abbreviated German version of the Sense of Competence Questionnaire among informal caregivers of relatives who had a stroke: development and validation.

Caregiver burden is a main outcome domain in caregiver intervention research. A recommended instrument for measuring burden is the Sense of Competence Questionnaire (SCQ). In this study, we evaluated the psychometric properties of the German version of the SCQ with informal caregivers of stroke patients. Baseline data of a randomized controlled trial (n = 122) and survey data (n = 76) of caregivers of stroke patients were used. Data were collected at the caregiver's or the care receiver's home or over the telephone. We evaluated the homogeneity, the construct validity, and the clinical validity of the German version and the homogeneity of a new abbreviated version. The homogeneity of the SCQ indicates good reliability (Cronbach's alpha: 0.89). The three-factor structure of the SCQ was mostly confirmed through principal components analyses using oblimin rotation. Clinical validity was supported through correlations between sense of competence and burden (r = -0.51), depression (r = -0.52), and care recipient's cognitive function (r = 0.36). Sixteen items with consistent factor loadings were extracted and proposed as a new abbreviated version of the SCQ (Cronbach's alpha: 0.84). The abbreviated German rendition of the SCQ version that was validated in this study offers a consistent version that can be applied across different languages and among caregivers of stroke survivors or people with dementia.