Name two commonly used root cause analysis methods.

Name two commonly used root cause analysis methods.

• A. Failure mode effects analysis and fault tree analysis.
• B. Plan-Do-Check-Act cycle and statistical process control.
• C. 5 Whys technique and Fishbone (Ishikawa) diagram.
• D. Failure mode analysis and risk scoring.

Answer: (C)

Root cause analysis relies on structured techniques to uncover the underlying reasons behind a problem. Two commonly used methods are the 5 Whys technique and the Fishbone (Ishikawa) diagram.

The 5 Whys technique digs downward by repeatedly asking “why,” helping you peel back layers of symptoms to reach the fundamental cause. It’s simple, fast to apply, and works well for teams that want to start uncovering root causes without requiring complex tools.

The Fishbone diagram provides a visual map of potential causes by categories such as People, Process, Equipment, Materials, Environment, and Methods. This helps teams brainstorm and organize possible root causes in a way that highlights where deeper dives are needed.

Using them together gives both a straightforward questioning approach and a structured way to visualize and explore all plausible factors contributing to the issue.

Other options pair methods that aren’t primarily used for root-cause analysis. For example, failure mode and effects analysis looks at potential failure modes before problems occur, while Plan-Do-Check-Act and Statistical Process Control focus more on process improvement and ongoing control rather than tracing a specific problem’s root cause.