Exploring clinician-reported assessments of capacity and performance qualifiers in the ICF: a scoping review

Background: The International Classification of Functioning, Disability and Health (ICF) provides a standardized rating system called "qualifiers" to describe capacity and performance, reflecting what a person can do and what a person does, respectively, yet their clinician-reported use remains conceptually and methodologically unclear. Objective: To map and describe clinician-reported assessments linked to capacity and performance qualifiers, and to examine how these qualifiers have been operationalized in practice. Methods: A scoping review was conducted following PRISMA-ScR guidelines. Systematic searches were performed in five bibliographic databases and grey literature sources from 2001 to August 2025. The protocol was registered prospectively on the Open Science Framework. Studies were included if they described clinician-reported assessments applying capacity and/or performance qualifiers in accordance with original ICF definitions. Results: Five studies met the inclusion criteria. Identified assessments were confined to a narrow range of Mobility categories, namely walking and use of the upper extremities. Most studies retrofitted existing clinical tests to qualifiers using heterogeneous approaches, including percentage-based thresholds, normative distributions, or clinically defined descriptors. Only one study developed an assessment specifically designed for qualifier use. Explicit differentiation between capacity and performance was rarely reported, and validation of qualifier thresholds was limited. Conclusions: Nearly a quarter of a century after the adoption of the ICF, clinician-reported use aligned with original ICF capacity and performance definitions remains limited, conceptually ambiguous, and methodologically inconsistent. Clearer conceptual definitions and internationally agreed, category-specific criteria are needed to enable meaningful, reliable, and comparable clinician-reported assessments of functioning.