Which theory visualizes holes in a system lining up to produce an accident condition?

Which theory visualizes holes in a system lining up to produce an accident condition?

• A. Swiss Cheese Theory
• B. Domino Theory
• C. Human Factor Theory
• D. Multiple Factor Theory

Answer: (A)

The main idea here is that accidents happen when weaknesses in several layers of defense line up, like holes in slices of Swiss cheese. Each layer of protection or barrier has potential gaps caused by latent conditions or active failures. Normally, these gaps don’t align, so a hazard is stopped. But when holes in different defenses align at once, a path exists for a mistake or hazard to reach the system’s vulnerable point, leading to an accident. This model helps explain why incidents can occur even when no single factor guarantees failure—it’s the combination of multiple small weaknesses that aligns to produce harm. For example, a factory might have a design flaw (a hole in the barrier), an inadequate procedure (another hole), and a lapse in supervision or training (yet another hole). If all three align with the triggering event, the hazard slips through all defenses and an accident happens; if any one barrier holds, the incident is prevented. The other theories don’t capture this hole-alignment, layered-barrier concept as directly: a linear chain of events, a focus on human performance, or a more general mix of factors without the explicit defense-in-depth analogy.

The main idea here is that accidents happen when weaknesses in several layers of defense line up, like holes in slices of Swiss cheese. Each layer of protection or barrier has potential gaps caused by latent conditions or active failures. Normally, these gaps don’t align, so a hazard is stopped. But when holes in different defenses align at once, a path exists for a mistake or hazard to reach the system’s vulnerable point, leading to an accident. This model helps explain why incidents can occur even when no single factor guarantees failure—it’s the combination of multiple small weaknesses that aligns to produce harm. For example, a factory might have a design flaw (a hole in the barrier), an inadequate procedure (another hole), and a lapse in supervision or training (yet another hole). If all three align with the triggering event, the hazard slips through all defenses and an accident happens; if any one barrier holds, the incident is prevented. The other theories don’t capture this hole-alignment, layered-barrier concept as directly: a linear chain of events, a focus on human performance, or a more general mix of factors without the explicit defense-in-depth analogy.