How to do a root cause analysis in 5 steps
1. Recognise the problem
Write one clear statement: what happened, where, when and what it cost in time, money or safety. A vague problem leads to a vague cause.
2. Observe the facts
Collect evidence: photos, readings, records, alarms and what people saw. Separate facts from assumptions and list what you still need to confirm on site.
3. Obtain the root cause
Use 5 Whys, a fishbone diagram or both. Keep going until you reach a cause the organisation can control, such as a procedure, design or maintenance gap. Stopping at "human error" is the most common mistake.
4. Tackle the root cause
Agree specific actions. Give each an owner and a target date, and include at least one action that prevents the problem, not just repairs it.
5. Sustain the fix
Update the procedure or maintenance plan, track the actions to closure, and check after a few weeks or months that the problem has not come back.
Common mistakes
- Stopping at the first answer or at human error.
- Blaming a person instead of the system.
- Writing actions without owners or dates.
- Never checking whether the fix worked.
Do it faster with RapidRCA
RapidRCA follows these five steps for you. Describe the failure or add a photo or file, answer a few questions, and edit the result.
Frequently asked questions
How long does a root cause analysis take?
A simple one can take an hour, and a serious event takes longer because of evidence gathering. The step that matters most is following the actions through.
What is the difference between 5 Whys and a fishbone?
5 Whys follows one chain of causes in depth. A fishbone widens the search across categories. Many investigations use both.
Describe the failure or add a photo or file, and RapidRCA builds the 5 Whys, fishbone, actions and report, using the ROOTS method.
Start an RCA
Last updated 14 October 2026. These guides explain a method and give examples. Always follow your equipment manufacturer's manual, your site procedures and applicable regulations.