Root Cause Analysis
A problem-solving method that identifies the fundamental reason behind a variance, defect, or risk. A single root cause can lead to multiple variances, defects, or risks.
Key Points
- Traces symptoms back to their source using techniques like 5 Whys, fishbone (Ishikawa) diagrams, and fault tree analysis.
- Aims to prevent recurrence by fixing causes rather than treating symptoms.
- One cause may drive several issues across scope, schedule, cost, quality, or risk.
- Outputs inform corrective and preventive actions, change requests, risk responses, and lessons learned updates.
Example
On a construction project, multiple walls fail inspection due to incorrect dimensions, causing rework and schedule slippage. The team performs root cause analysis and finds that outdated drawings were distributed to several crews. They correct the document control process, retrain staff, and issue a change request to prevent further defects.
PMP Example Question
A project is experiencing recurring test failures and rising cost variance. What should the project manager use to discover the fundamental reason and prevent recurrence?
- Trend analysis
- Root cause analysis
- Reserve analysis
- Fast tracking
Correct Answer: B — Root cause analysis
Explanation: Root cause analysis is used to identify the underlying reason for defects or variances so the team can implement targeted preventive and corrective actions.
