The Swiss Cheese Model is a metaphor used in risk analysis and risk management. It illustrates how various layers of defence, represented by slices of Swiss cheese, can have holes – vulnerabilities. When these holes align across different layers, they can lead to a failure or an incident. The model emphasizes that no single layer of defence is foolproof, but having multiple layers can reduce the risk of failures or errors slipping through the system. Each layer represents a different defence or mitigation strategy.