Worst-case scenario

A worst-case scenario is a concept in risk management wherein the planner, in planning for potential disasters, considers the most severe possible outcome that can reasonably be projected to occur in a given situation. Conceiving of worst-case scenarios is a common form of strategic planning, specifically scenario planning, to prepare for and minimize contingencies that could result in accidents, quality problems, or other issues. The worst-case scenario is "[o]ne of the most commonly used alternative scenarios". A risk manager may request "a conservative risk estimate representing a worst-case scenario" in order to determine the latitude they may exercise in planning steps to reduce risks. Generally, a worst-case scenario "is settled upon by agreeing that a given worst case is bad enough. However, it is important to recognize that no worst-case scenario is truly without potential nasty surprises". In other words, ‘[a] “worst-case scenario” is never the worst case’, both because situations may arise that no planner could reasonably foresee, and because a given worst-case scenario is likely to consider only contingencies expected to arise in connection with a particular disaster. The worst-case scenario devised by a seismologist might be a particularly bad earthquake, and the worst-case scenario devised by a meteorologist might be a particularly bad hurricane, but it is unlikely that either of them will devise a scenario where a particularly bad storm occurs at the same time as a particularly bad earthquake. The definition of a worst-case scenario varies by the field to which it is being applied. For example, in environmental engineering", "[a] worst-case scenario is defined as the release of the largest quantity of a regulated substance from a single vessel or process line failure that results in the greatest distance to an endpoint". In this field, "[a]s in other fields, the worst-case scenario is a useful device when low probability events may result in a catastrophe that must be avoided even at great cost, but in most health risk assessments, a worst-case scenario is essentially a type of bounding estimate".