Root Cause Analysis
Root cause analysis is a structured investigation used to identify the underlying conditions that allowed a failure or problem to occur and determine actions that reduce recurrence.
What this term means in maintenance
Root cause analysis is a structured investigation used to identify the underlying conditions that allowed a failure or problem to occur and determine actions that reduce recurrence.
Purpose of root cause analysis
Repairing the failed component restores operation. Root cause analysis asks why the failure occurred, why existing controls did not prevent or detect it, and what must change to reduce recurrence.
Evidence commonly reviewed
A useful investigation may review:
- Failure history
- Operating conditions
- Inspection and preventive-maintenance records
- Photos and damaged parts
- Alarm and process data
- Lubrication, alignment, and installation records
- Procedures and work instructions
- Human, design, and organizational factors
Common methods
Methods include:
- 5 Whys
- Fishbone diagram
- Fault tree analysis
- FMEA
- Cause-and-effect mapping
- Evidence timelines
The method should match the complexity and consequence of the event.
Practical example
A bearing failed because contamination entered the housing. Further investigation found a damaged seal, an unsuitable washdown method, and no inspection step for seal condition. Replacing the bearing alone would not control recurrence.
Effective actions
Actions should remove or control the verified causes. They may include design changes, revised PM tasks, improved detection, training, spare-parts changes, operating limits, or better procedures.
Common mistake
Stopping at conclusions such as “operator error” or “lack of lubrication” is usually too shallow. The investigation should examine why the condition was possible and why the existing controls failed.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
5 Whys Analysis
The 5 Whys is a simple root cause analysis technique that repeatedly asks why a problem occurred until the team reaches an evidence-supported and actionable underlying cause.
Fishbone Diagram
A fishbone diagram is a cause-and-effect analysis tool used to organize possible causes of a problem into logical categories before evidence is used to confirm the real causes.
Failure Mode and Effects Analysis
Failure Mode and Effects Analysis, or FMEA, is a structured method for identifying how an asset or process may fail, the effects of each failure, existing controls, and actions needed to reduce risk.
Glossary FAQs
- When should root cause analysis be performed?
Use it for significant, repeated, high-risk, costly, or poorly understood failures where preventing recurrence justifies investigation.
- Is replacing the failed component a root cause?
No. Replacement restores function but does not explain why the component failed or why controls did not prevent the event.
- Which root cause analysis method should be used?
Use a method appropriate to the event’s complexity and consequence, such as 5 Whys, fishbone analysis, fault tree analysis, FMEA, or a formal evidence-based investigation.