The "Swiss cheese" model of risk mitigation
The Swiss Cheese model is a metaphor used in safety science. It illustrates how accidents typically occur due to multiple, overlapping failures rather than a single cause.
Each "slice" of cheese represents a layer of defense (such as safety measures or procedures) within a system.
Each “hole” in the cheese symbolizes a potential weakness or failure.
If a hole in one slice of cheese is covered by a solid part of the next slice, you have a partial problem but is not (yet) a catastrophe.
Even if a slice of cheese is only 5% holes, there’s still a small chance that two holes could align, and that's when you could have a serious problem.