five-whys

• Investigating recurring problems
• Debugging system failures
• Understanding customer churn
• Analyzing project delays or budget overruns
• Post-mortem analysis
• Process improvement initiatives

The Method

```

Problem Statement

↓

Why? → Answer 1

↓

Why? → Answer 2

↓

Why? → Answer 3

↓

Why? → Answer 4

↓

Why? → Answer 5

↓

Root Cause Identified

↓

Solution Implementation

```

Key Principles

| Principle | Description |

| ---------------------------- | ------------------------------------ |

| Facts over assumptions | Base questions on data, not guesses |

| Systems over individuals | Focus on process failures, not blame |

| Flexibility | Go beyond 5 questions if needed |

| Verification | Validate findings with evidence |

Standard Approach

For each iteration, ask:

• Why did this happen?
• What caused this situation?
• What led to this outcome?

Alternative Phrasing (Less Confrontational)

When direct "why" questions feel threatening, use softer alternatives:

#### Root Cause Investigation

| Instead of... | Try... |

| -------------------- | ------------------------------------- |

| Why did this happen? | What was going on when this happened? |

| Why did you do that? | What were you trying to accomplish? |

| Why is this broken? | How do you suppose we ended up here? |

#### Understanding Motivation

| Instead of... | Try... |

| --------------------- | ------------------------------------------ |

| Why do you want this? | What happens if we don't get this done? |

| Why does this matter? | What problems does this solve? |

| Why is this urgent? | What do you think will happen if we delay? |

#### Understanding Decisions

| Instead of... | Try... |

| ------------------------------- | --------------------------------------------- |

| Why did leadership decide this? | What were the reasons we went this direction? |

| Why this approach? | How do you see this working long term? |

Step 1: Define the Problem

Be specific and measurable:

```

❌ Bad: "The system is slow"

✅ Good: "Page load time increased from 2s to 8s after the March release"

❌ Bad: "Customers are unhappy"

✅ Good: "Customer churn increased by 40% over three months"

```

Step 2: Iterate Through Whys

Document each level clearly:

```

Problem: Customer churn increased by 40%

1. Why? → Customers canceling after free trial
2. Why? → Not seeing enough value during trial
3. Why? → Not completing the onboarding process
4. Why? → Onboarding too complex, requires too much setup
5. Why? → Product lacks automation and intelligent defaults

Root Cause: Poor onboarding experience due to lack of automation

```

Step 3: Identify Solutions

Target the root cause, not symptoms:

```

Symptom-level fix (avoid):

├── Offer discounts to retain customers

└── Send more reminder emails

Root cause fix (preferred):

├── Build automated data import

├── Create intelligent defaults by industry

├── Simplify onboarding to 3 steps

└── Add progress indicators

```

After completing analysis, document as:

```markdown

Problem Statement: [Clear, measurable problem description]

Analysis Date: [Date]

Participants: [Who was involved]

Question Chain

1. Why? [First answer with evidence]
2. Why? [Second answer with evidence]
3. Why? [Third answer with evidence]
4. Why? [Fourth answer with evidence]
5. Why? [Fifth answer with evidence]

Root Cause

[Identified root cause - the systemic issue to address]

Recommended Solutions

| Priority | Solution | Expected Impact | Effort |

| -------- | ------------ | --------------- | -------- |

| High | [Solution 1] | [Impact] | [Effort] |

| Medium | [Solution 2] | [Impact] | [Effort] |

| Low | [Solution 3] | [Impact] | [Effort] |

Success Metrics

• [How will we measure if the solution worked?]

```

Manufacturing Example (Toyota Original)

```

Problem: Machine stopped operating

1. Why? → Motor overheated
2. Why? → Wasn't lubricated enough
3. Why? → Oil pump failed
4. Why? → Filter was clogged
5. Why? → No regular maintenance schedule

Root Cause: Lack of preventive maintenance procedures

Solution: Implement maintenance schedule and checklist

```

SaaS Example

```

Problem: Customer churn increased 40%

1. Why? → Customers canceling after free trial
2. Why? → Not seeing enough value during trial
3. Why? → Not completing onboarding
4. Why? → Onboarding too complex
5. Why? → Lacks automation and smart defaults

Root Cause: Poor onboarding experience

Solutions:

• Automated data import from popular tools
• Intelligent defaults based on industry
• Simplified 3-step onboarding
• In-app progress indicators

Result: 60% decrease in churn, 35% increase in trial conversion

```

Software Bug Example

```

Problem: Production API returning 500 errors

1. Why? → Database queries timing out
2. Why? → Query taking 30+ seconds
3. Why? → Missing index on frequently queried column
4. Why? → Index was dropped during migration
5. Why? → Migration script lacked index recreation step

Root Cause: Incomplete migration testing process

Solutions:

• Add index verification to migration checklist
• Implement automated index coverage tests
• Create pre-production performance benchmarks

```

Do

• Use data - Support answers with evidence and metrics
• Involve diverse perspectives - Different viewpoints reduce blind spots
• Focus on systems - Ask "what process failed?" not "who failed?"
• Document everything - Create audit trail for future reference
• Verify root cause - Test that fixing it would prevent recurrence

Avoid

• Stopping too early - Surface answers are usually symptoms
• Personal blame - "John made a mistake" is never the root cause
• Single path - Complex problems may have multiple root causes
• Assumptions - Always verify with data
• Skipping steps - Each "why" should logically follow the previous

• Give people time to respond - embrace silence
• Ask one question at a time
• Resist the urge to clarify before they answer
• Focus on curiosity rather than interrogation
• Frame as collaborative problem-solving

The Five Whys works well alongside:

| Method | Combined Use |

| -------------------- | -------------------------------------- |

| Kaizen | Continuous improvement cycles |

| Six Sigma | DMAIC problem-solving |

| Fishbone Diagram | Visualizing multiple cause categories |

| Pareto Analysis | Prioritizing which problems to analyze |

| Post-mortem | Incident review sessions |

• [Toyota Production System](https://en.wikipedia.org/wiki/Toyota_Production_System)
• [Taiichi Ohno's Workplace Management](https://www.goodreads.com/book/show/843519.Workplace_Management)
• [The Lean Startup - Eric Ries](https://theleanstartup.com/)