Which root cause analysis method is commonly used to categorize potential causes across categories such as people, process, equipment, and environment?

Which root cause analysis method is commonly used to categorize potential causes across categories such as people, process, equipment, and environment?

• A. Plan-Do-Check-Act cycle.
• B. Fishbone (Ishikawa) diagram.
• C. 5 Whys technique.
• D. Failure mode effects analysis.

Answer: (B)

A Fishbone diagram (Ishikawa diagram) is used to organize potential causes into categories such as people, process, equipment, and environment. This visual tool lays out the problem at the head and builds a spine with major categories as bones, then adds sub-causes along each bone. It helps a team brainstorm widely, ensuring factors from different domains are considered and showing how they might interrelate. The result is a clear map of where to collect data and what to test to verify root causes, guiding focused improvement efforts.

Other methods serve different purposes: the Plan-Do-Check-Act cycle guides implementing and refining improvements; the 5 Whys drills down into a single causal chain but doesn’t provide a structured, multi-category overview; and Failure Mode and Effects Analysis identifies potential failure modes and their effects with risk ranking rather than organizing causes by domain.