Which statement best describes how HPI views errors?

• A. Errors are random and unpreventable
• B. Errors arise from individual fault only
• C. Errors result from equipment failure
• D. Errors reflect weaknesses in both people and systems, requiring defenses

Answer: (D)

In HPI thinking, errors are not just random events or the sole fault of a single person, nor are they only about equipment failing. They come from how people interact with the systems around them, including procedures, tools, environment, and organizational practices. Because performance is shaped by both people and the surrounding system, the most effective view is that errors reveal weaknesses in both areas and that we should build defenses to catch and prevent mistakes at multiple points.

This approach leads to practical defenses: clear and well-designed procedures, thoughtful human-centered equipment design, thorough training, checklists, independent verification, redundant safeguards, and a culture that encourages reporting and learning from near-misses. By strengthening both the people and the system, you reduce the chance that an individual slip leads to a problem.

That’s why the statement describing errors as stemming from weaknesses in both people and systems and requiring defenses is the best fit.