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.

[2] Generally, a worst-case scenario "is settled upon by agreeing that a given worst case is bad enough.

[3] In other words, ‘[a] “worst-case scenario” is never the worst case’,[4] both because situations may arise that no planner could reasonably foresee,[1] and because a given worst-case scenario is likely to consider only contingencies expected to arise in connection with a particular disaster.

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".

[5] 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".