Key Scenarios: When making a strategy you make assumptions about the future. At a minimum you should have one "best"-case scenario, one "worst"-case scenario and one "normal"-case scenario. In financial projection you could use the average of these scenarios by attaching a probability to each scenarios. (20% - Best, 60 % - Normal , 20% - Worst ) .

By focusing on the underlying drivers of what causes the 3 different scenarios, you can create extreme situations. This gives you a tool to test the robustness of your strategy. Many of these drivers are discussed in the Pestel tool.

How to test the robustness of your strategy?
Identify the few underlying drivers that determine the development of your market. Make some "black swan" scenarios where one or more drivers go “off the chart”. How will your strategy cope with such a scenario? How can you change your strategy to cope with such scenarios?