Tripod Beta vs 5 Whys: which incident investigation method should you use?
5 Whys is the entry-level tool of root-cause analysis: ask 'why?' five times until you reach a controllable cause. Tripod Beta sits at the opposite end — a structured methodology that decomposes incidents into agent–hazard–target trios, classifies barrier failures, and traces preconditions and latent failures across eleven General Failure Types.
Both have their place. The question is not which is better in the abstract — it is which fits the severity, complexity and audit posture of the incident in front of you.
| Feature | Tripod Beta | 5 Whys |
|---|---|---|
| Time per investigation | 8–16 hours analyst time | 30 minutes |
| Causal model | Multi-layered tree (active failure, preconditions, latent failures) | Single linear chain |
| Identifies organisational causes | Yes — via 11 GFTs | Rarely; depends on facilitator skill |
| Suitable for major incidents | Yes — gold standard | Not by itself |
| Defensibility to regulators | High — auditable trios + barriers + GFTs | Low — narrative only |
| Training required | 2–5 days, ideally Tripod-certified | 1 hour briefing |
| Cost per investigation | From £99 with RiskoPilot | Effectively free |
| Best fit | High-severity, high-hazard, regulated industries | Low-severity quality issues, kaizen workshops |
Our verdict
Use 5 Whys for low-severity, single-cause incidents where a quick fix is genuinely the right answer. Use Tripod Beta — or a methodology of comparable depth — for any incident with major-hazard exposure, regulator visibility, or where the same problem keeps recurring. Cutting corners on serious incidents creates a false sense of closure that catches up with you on the next event.
Frequently Asked Questions
Sources & References
- Tripod Beta — Guidance on Use — Energy Institute / Shell, 2014
- Human Error — James Reason — Cambridge University Press, 1990
- ISO 45001:2018 — Occupational health and safety management — International Organization for Standardization, 2018