What is root cause analysis?
Root cause analysis (RCA) is a structured approach to identifying the fundamental reason a problem occurred. A root cause is one that, if removed, prevents recurrence.
RCA in 6 steps
- Define the problem precisely — what, where, when, how much.
- Collect data and evidence.
- Identify possible causes (fishbone: people, method, machine, material, measurement, environment).
- Narrow down with data and the 5 Whys.
- Fix the root cause and verify.
- Standardise and share the learning.
Main RCA tools
| Tool | Best for |
|---|---|
| 5 Whys | Simple, single-chain problems |
| Fishbone (Ishikawa) | Exploring many possible causes |
| Pareto chart | Finding the few causes behind most problems |
| Fault tree | Complex, safety-critical failures |
Common mistakes to avoid
- Stopping at “human error”.
- Jumping to solutions before collecting data.
- Not checking that the fix actually worked.
How DOOfy helps
RCA is faster when the evidence is already connected. AIMOS One links what happened across sales, stock, people and equipment, so investigations start from data — and NIMMI can help gather it.
Frequently asked questions
What is the difference between a root cause and a contributing cause?
A contributing cause made the problem more likely; the root cause is the fundamental one that, if removed, prevents recurrence.
What is a fishbone diagram?
A cause-and-effect diagram, developed by Kaoru Ishikawa, that groups possible causes into categories such as people, methods, machines, materials, measurement and environment.