Measuring a Family Sense of Coherence: A Rasch-based Study Extending Dyadic Data Analyses

Abstract

Background Family sense of coherence (FSOC) seems to reduce distress in the family and promote the well-being of the family. Therefore, getting accurate measurements for families with long-term illnesses is of particular interest. This study aims to examine the measurement properties of the Family Sense of Coherence Short Scale (FSOC-S12) for two set-ups (dyadic- and single-informant perspectives) and to evaluate the relationship between the two set-ups and the consequences of their use. Methods Racked and stacked data from 151 dyads were analyzed according to the Rasch model. Results Notably, both set-ups showed measurement properties with minor deviations from the Rasch model according to fit statistics. However, most items had disordered thresholds and some problems with local dependency. Item hierarchies were similar in both set-ups and there was no differential item functioning (DIF) by role from the dyadic informant perspective. Four items showed DIF by informant role in the single-informant perspective. Conclusions The FSOC-S12 can be used to provide meaningful measures of the family’s view of the family’s ability as a whole (dyadic-informant perspective) or measures of the patient’s and family member’s own view of the family’s ability as a whole (single-informant perspective).