Managing the Complexity-Coherence Trade-Off in Clinical Reasoning: A Two-Stage Graph Ontology Based on WHO International Classifications.

backgroundClinical reasoning in contemporary practice often involves ill-structured, poorly defined problems that span the biopsychosocial domain and require reasoning under high relational complexity. Despite sustained scholarly attention to clinical reasoning, few models are both theoretically grounded and usable for clinicians who face this complexity. At the same time, the World Health Organization Family of International Classifications (WHO-FIC) offers a rich but complex ontology that was not designed primarily to support clinical reasoning in practice.

aimTo develop a two-stage WHO-FIC-based ontological model of clinical reasoning that is conceptually coherent yet remains cognitively tractable in the face of complexity.

methodsA conceptual analysis was undertaken. It integrated three strands: (1) WHO-FIC classification theory, including recent work on harmonisation; (2) empirical and theoretical literature on clinical reasoning; and (3) cognitive theories of bounded rationality, fast-and-frugal heuristics, relational complexity, and framing. These strands were used to derive design constraints for a clinically usable ontology. They were then synthesised into a two-stage, graph-based model designed to manage the complexity-coherence trade-off in clinical reasoning.

resultsStage 1 introduces a parsimonious triad-Body, Activity, and Environment-represented as a complete three-node graph with bidirectional relations. This triad provides an etiologically neutral and cognitively economical starting point for framing complex clinical problems. Stage 2 introduces three emergent constructs-Health Condition, Participation, and Intervention-derived compositionally from Stage 1 relations and aligned with ICD-11, ICF, and ICHI, respectively. The model supports iterative movement between stages through composition and decomposition. It incrementally increases complexity while keeping relational load within cognitively feasible bounds and preserves the value of diagnosis while reducing its tendency to dominate problem framing. A worked case illustrates how the ontology supports reasoning about complex, time-dependent problems through repeated movement between stages.

conclusionsThe proposed ontology addresses key ambiguities within WHO-FIC, including the relationship between Activity and Participation and the perceived hierarchical privileging of diagnosis. It offers a more coherent and cognitively usable framework while respecting limits on human reasoning and managing the complexity-coherence trade-off. The model provides a theoretically grounded heuristic scaffold for clinicians and educators who work with complexity. It also contributes to clinical reasoning literature by emphasising reasoning about concepts, not only cases, with implications for interprofessional education and practice.