Name two root-cause analysis methods commonly used in incident investigations.

Name two root-cause analysis methods commonly used in incident investigations.

• A. Ishikawa (Fishbone) diagram and Pareto chart.
• B. 5 Whys and Ishikawa (Fishbone) diagram.
• C. Fault Tree Analysis and Risk Matrix.
• D. Cause-and-effect matrix and Ishikawa.

Answer: (B)

In incident investigations, you want to uncover underlying factors that allow the problem to occur, not just the obvious symptom. Two well-established methods for this are the 5 Whys and the Ishikawa (Fishbone) diagram. The 5 Whys is a straightforward, repeatable questioning approach: ask why the problem happened, then for each answer ask why again, continuing until you reach a root cause. This helps peel back layers of causes and often reveals systemic issues rather than one-off mistakes. The Ishikawa diagram offers a visual way to brainstorm and organize possible causes into categories such as People, Process, Equipment, Materials, Environment, and Management, showing how different factors may contribute to the incident and how they interrelate. Using them together combines a thorough brainstorming framework with a method to drill down into the true underlying cause, making investigations more effective. Other options mix tools that aren’t primarily about identifying root causes in the same way. For example, some choices pair a root-cause technique with a prioritization tool, which doesn’t focus on uncovering the root cause; others include a risk matrix that’s about assessing likelihood and impact rather than pinpointing causal factors; and a cause-and-effect matrix is related but not as universally central to incident RCAs as the combination of 5 Whys and Ishikawa.

In incident investigations, you want to uncover underlying factors that allow the problem to occur, not just the obvious symptom. Two well-established methods for this are the 5 Whys and the Ishikawa (Fishbone) diagram. The 5 Whys is a straightforward, repeatable questioning approach: ask why the problem happened, then for each answer ask why again, continuing until you reach a root cause. This helps peel back layers of causes and often reveals systemic issues rather than one-off mistakes. The Ishikawa diagram offers a visual way to brainstorm and organize possible causes into categories such as People, Process, Equipment, Materials, Environment, and Management, showing how different factors may contribute to the incident and how they interrelate. Using them together combines a thorough brainstorming framework with a method to drill down into the true underlying cause, making investigations more effective.

Other options mix tools that aren’t primarily about identifying root causes in the same way. For example, some choices pair a root-cause technique with a prioritization tool, which doesn’t focus on uncovering the root cause; others include a risk matrix that’s about assessing likelihood and impact rather than pinpointing causal factors; and a cause-and-effect matrix is related but not as universally central to incident RCAs as the combination of 5 Whys and Ishikawa.