Final answer:
A trigger in contingency planning is a specific event or condition that signals the enactment of the plan, acting as a decision-making guide in critical situations.
Step-by-step explanation:
In the context of implementing a contingency plan, a trigger can be understood as a specific event or condition that signals the need to enact the contingency measures laid out in the plan. Much like a "break glass in case of emergency" mechanism, the trigger is the 'glass' that once 'broken' or activated, sets the plan into motion. It's designed to provide a clear point at which the plan should be implemented, preventing any hesitation or confusion during critical situations.
When facing asymmetric risk as depicted in Figure 20.1, decisions between pursuing Plan A or Plan B depend on the assessment of the threat. A trigger in this scenario would be a predetermined factor or threshold that once crossed, indicates that sticking to Plan A could lead to catastrophic outcomes, therefore shifting to Plan B, although not ideal if the threat is not real, would be the conservative and safer path. Thus, the trigger acts as a crucial decision-making guide in situations where risks are not evenly balanced.