The "5L" framework of diagnostic reasoning: A stepwise scaffold to support clinician educators

Diagnostic reasoning (DR) is a core clinical skill, yet its teaching remains variable. We introduce the "5L" framework as a bedside teaching scaffold that gives educators and learners a shared, stepwise set of prompts for DR during individual encounters. By asking, "What's Lethal? What's Likely? What's Logical? What's Lurking? and What's Lingering?, we use a clinical case to systematically illustrate its use in guiding probability assessment, diagnostic fit, uncertainty reduction, and shared decision-making. This theoretically informed framework aims to standardize DR instruction and improve integration of risk, probability, illness scripts, problem representation, uncertainty, and patient values. Future work should evaluate its impact on learning and patient outcomes.