Clinical Reasoning and Threshold Concepts
We read with interest McBee and colleagues’1 study of resident physicians’ clinical reasoning. Using an established framework of 24 clinical reasoning tasks to analyze residents’ responses to clinical scenarios, they found that use of these tasks occurred in a varied, rather than sequential manner, and that residents described new tasks, such as reprioritization of differential diagnosis, which were not among the original 24.1 The authors applied ecological psychology to their findings, arguing that affordances (opportunities for actions) and effectivities (abilities for action) informed how individual residents reasoned about a given clinical scenario, thus explaining interindividual variability in the order of verbalized reasoning tasks. This study is an important contribution to the growing literature on clinical reasoning processes, and we advocate for a corresponding examination of key knowledge acquisition during residency. Elucidating reasoning processes without parallel consideration of context-specific knowledge evokes what Regehr2 has called “the problem of generalizable solutions.” “Weak” problem-solving routines emphasize processes and are generalizable to many situations but are of limited value for a particular situation, whereas “strong” routines require specific knowledge of a particular situation that may not transfer to other contexts.
Identifying and applying threshold concepts may be one way to bridge the gaps between weak and strong routines, and between processes and knowledge in clinical reasoning. Threshold concepts are “portals of entry” into mastery of a discipline and often crystallize around troublesome knowledge.3 For example, “uncertainty” has been identified as a threshold concept in medicine. Residents in the study by McBee and colleagues frequently verbalized diagnostic uncertainty, and learning to work with this uncertainty is key to successful clinical reasoning. Another example would be interpreting a peripheral blood film in a patient with anemia; context-specific knowledge contributes to affordance (availability of a blood film) and effectivity (being able to interpret the blood film findings). Clinical reasoning processes must be coordinated with acquisition and application of essential context-specific knowledge, some of which may be characterized as “threshold concepts,” in order to optimize diagnostic accuracy.