In the Swiss Cheese Model, which statement is true?

• A. It posits that multiple layers of defense exist, and when holes align, an error occurs.
• B. It describes a single cause of accident.
• C. It focuses on individual blame.
• D. It assumes there is no defense in health care.

Answer: (A)

The main idea is that safety relies on multiple layers of defense, each with its own holes. In the Swiss Cheese Model, these layers are like slices of cheese with gaps representing latent conditions and active errors. An adverse event occurs when the holes line up across several layers, allowing a hazard to pass through all defenses. This explains why accidents in health care often involve a combination of factors rather than a single cause and why focusing on system design and defenses is crucial. The other statements don’t fit because there isn’t just one cause, there isn’t an emphasis on blaming individuals, and there are indeed defenses present in health care.