5 Why vs Fishbone vs ICAM vs Apollo Root Cause
Root Cause Analysis
Method Comparison
- 5 Why - Quick and Simple Linear Analysis
- Fishbone (Ishikawa) - Grouping Potential Causes
- ICAM - For Rule Based or Regulatory Issues
- Apollo RCA - Comprehensive Prevention of Failures
When to use each RCA Tool
Quick Overviews
5 Whys – A simple questioning technique that digs into problems quickly but often stops at surface-level symptoms.
Fishbone (Ishikawa) – A brainstorming diagram that groups potential causes into categories; useful for generating ideas, but not for proving causes.
ICAM – A structured, systems-based approach common in aviation, mining, and rail industries; strong on incident classification but can miss underlying causal pathways.
Apollo Root Cause Analysis (ARCA) – A rigorous, evidence-based methodology that maps cause-and-effect pathways to uncover true root causes and develop effective, lasting solutions.
Apollo RCA Key Difference
Unlike other tools where teams often guess, vote, or assume the “most likely” cause, Apollo RCA scientifically uncovers and validates the actual root causes through structured analysis.
This makes Apollo the most reliable method for eliminating recurrence and preventing costly repeat failures.
Comparison Guide
Ready Reference Chart
| Criteria | 5 Whys | Fishbone Diagram (Ishikawa) | ICAM (Incident Cause Analysis Method) | Apollo Root Cause Analysis (ARCA) |
|---|---|---|---|---|
| Time to Execute | Very quick (minutes–1 hr) | Quick to moderate (1–2 hrs) | Moderate to long (2–6 hrs) | Longer (½–2 days depending on complexity) |
| Depth of Analysis | Shallow (linear chain) | Moderate (categorical brainstorming) | Structured (systems-based) | Very deep (causal pathways, systemic & latent causes) |
| People Required | 1 person | 2–3 people | 3–5 people | 5–8 people (multidisciplinary) |
| Documentation | Minimal notes | Diagram + notes | Incident report + evidence | Cause & Effect Chart + investigation report |
| Training Required | None | Minimal | Moderate (ICAM training) | High (Apollo certification preferred) |
| % Chance of Failure Recurrence (Est.) | 60–70% | 40–50% | 20–30% | <10% (highest effectiveness) |
| Strengths | Speed, simplicity | Visual, easy to brainstorm | Regulatory alignment | Comprehensive, evidence-based, prevents recurrence |
| Weaknesses | Oversimplified, symptom-focused | Misses systemic factors | Resource-intensive, industry-specific | Time & resource investment, skilled facilitation required |
| Best Use Case | Small/simple issues | Categorising multiple possible causes | Safety incidents | Critical, complex, recurring, high-cost problems |
Discover Apollo Root Cause Analysis Training
If your organisation is serious about eliminating recurring problems, reducing downtime, and building a stronger safety and reliability culture, the next step is clear: invest in Apollo Root Cause Analysis (ARCA) training.
At Root Cause Australia, we deliver certified Apollo RCA training designed for engineering managers, operations leaders, safety professionals, and frontline teams. Unlike other problem-solving tools, Apollo RCA provides a structured, evidence-based framework that helps your people:
Identify true root causes instead of guessing or voting on “most likely” causes.
Build cause-and-effect charts that reveal systemic issues often hidden by surface-level analysis.
Develop long-lasting solutions that reduce failure recurrence and prevent costly repeat incidents.
Improve team capability with practical exercises and real-world case studies tailored to your industry.
Stop Addressing the Symptoms. Start Solving the Cause
Choose Apollo Root Cause Training
No more recurring breakdowns, safety incidents or missed KPIs.
The Apollo RCA method combined with RealityCharting Software gives you a proven 4-Steo system to fix failures and prevent them from coming back.
Globally Recognised
Recognised globally as one of the most effective incident investigation methods
Expert Training
Delivered by experienced facilitators with engineering and reliability backgrounds.
Flexible Delivery
Flexible training formats: online sessions, in-person workshops, and customised in-house delivery.
Professional Certification
Certification included, with access to RealityCharting software and exclusive investigation templates.
Not Ready Yet?
Start with a Free RCA Toolkit
- 5 Whys Template
- 5 Why / Fishbone / ICAM / ARCA Comparisson Tool
- Apollo RCA Case Study
- Apollo RCA Trigger Guideline
- RCA Readiness Checklist