Takes one event judged unlikely but devastating, postulates it has happened, and reasons backwards to the pathways that could produce it — returning the impact, 2–4 distinct pathways with their triggers, observable early-warning indicators, and a proportionate hedge (High-Impact/Low-Probability and "What If?" Analysis, US Tradecraft Primer 2009). Use when a severe scenario is being dismissed as improbable — "what if the sole supplier were cut off?", "stress-test how this unlikely event could actually happen", "run a high-impact/low-probability analysis". Not for a decision assumed to have failed (`premortem-analysis`) or a set of plausible futures (`scenario-planning`).
