- Objective: Many different assessment tools are used to assess functioning in rehabilitation; this limits the comparability and aggregation of respective data. The aim of this study was to outline the development of an International Classification of Functioning, Disability and Health (ICF)-based interval-scaled common metric for 2 assessment tools assessing activities of daily living: the Functional Independence Measure (FIMTM) and the Extended Barthel Index (EBI), used in Swiss national rehabilitation quality reports.
Methods: The conceptual equivalence of the 2 tools was assessed through their linking to the ICF. The Rasch measurement model was then applied to create a common metric including FIMTM and EBI.
Subjects: Secondary analysis of a sample of 265 neurological patients from 5 Swiss clinics.
Results: ICF linking found conceptual coherency of the tools. An interval-scaled common metric, including FIMTM and EBI, could be established, given fit to the Rasch model in the related analyses.
Conclusion: The ICF-based and interval-scaled common metric enables comparison of patients and clinics functioning outcomes when different activities of daily living tools are used. The common metric can be included in a Standardized Assessment and Reporting System for functioning information in order to enable data aggregation and comparability.
Keywords: Barthel Index; Functional Independence Measure; Rasch Measurement Model; activities of daily living; outcome assessment (healthcare); psychometrics; quality in healthcare; rehabilitation.