You can never accurately predict what's going to happen. Some efforts come close.

For example, models looking at the weather can achieve more than 90% accuracy. But crises are about change, and a model working from historical data may miss a dramatic and new change.

Knowing how people will respond in different situations is essential if you hope to keep them safe during a crisis. A type of simulation known as agent-based modelling attempts to understand interpersonal behaviours.

In stadiums, crowds of people can behave very differently depending on who they are and what kind of event has brought them to the venue. Depending on what sort of crowds are expected, architects may adjust the number of exits or the staircase designs to ensure a steady flow out of the venue during an evacuation. Modeling helps by getting the balance right.