A senior analyst recently remarked, “The first sign of trouble is often the reaction to the first sign.” This captures how feedback loops can escalate a seemingly isolated event into a systemic challenge. In stress testing, the goal is to identify these loops early. They often emerge when the response to an initial shock—such as a policy change or supply disruption—sets off a chain of further reactions, each magnifying the impact. Recognizing feedback loops means looking beyond the surface event to anticipate how markets, regulations, or even psychology might amplify consequences. A spiral, not a straight line, is the shape to watch for.

A classic example is a currency devaluation triggering capital flight, which then deepens the devaluation. The process can continue until an external intervention breaks the cycle. Scenario-based stress tests should ask: if the first shock triggers a reaction, does that reaction feed back into the original problem? Ignoring this possibility can leave gaps in preparedness. Each loop, if missed, is a potential blind spot that may undermine otherwise sound plans.

Secondary effects often take longer to emerge, but their impact can dwarf the original shock. For example, supply chain interruptions may cause immediate shortages, but the ripple effects—such as changes in consumer behavior or regulatory responses—can persist and compound. Scenario planners are advised to revisit the initial event after tracing its consequences, asking what new risks have emerged and how they might loop back into the system.

It is helpful to diagram these loops visually. Start with the initial event and map each consequential step. Where do arrows circle back to earlier stages? The process reveals where interventions may be most effective, and where new vulnerabilities might arise. Regularly updating these diagrams as new information comes in keeps scenario planning grounded and responsive.