Better Thinking

5 Whys anlysis

The 5 Whys Analysis is a simple yet powerful technique that identifies the root cause of a problem by repeatedly asking “Why?”, commonly used in quality management and process improvement.

Categories
Problem Solving
Target Users
Product ManagerProject ManagerOperations ManagersQuality Engineers
Applicable
Qulity ManagementRoot Cause AnalysisProcess Improvement
#root cause #Quality Management #Continuous Improvement #problem solving

🤔 What is the 5 Whys Analysis?

The 5 Whys Analysis is a problem-solving technique that identifies the root cause by asking “Why?” repeatedly.

  • Professional Definition: A structured method to drill down into the root cause of a problem by asking "why" multiple times.
  • Simple Example: Like a curious child asking “why” repeatedly, each answer takes you one step closer to the real cause.

📜 Origin & Key Figures

  • Background: Originated in the 1930s and popularized within the Toyota Production System.
  • Founder: Kiichiro Toyoda, son of Toyota’s founder Sakichi Toyoda.
  • Representative Users: Toyota, General Electric, Deming’s quality management.
  • Case: Toyota used the method to solve machine breakdowns, identifying design flaws instead of just fixing symptoms.

🛠 How to Use the Method

  1. Define the Problem Clearly
    • Write down the exact issue.
    • Tip: Be specific, avoid vague problems.
  2. Ask “Why” Repeatedly (usually 5 times)
    • Base each answer on facts, not assumptions.
    • Tip: Dig deeper, don’t settle for surface-level answers.
  3. Identify the Root Cause & Propose Solutions
    • Translate the final cause into actionable improvements.
    • Tip: Ensure the solution is practical and verifiable.

📚 Case Studies

  • Case 1 (Business/Management)

    Problem: Customer complaint about delivery delays.

    1. Why delay? – No stock.
    2. Why no stock? – Procurement not executed.
    3. Why procurement not executed? – System alert failed.
    4. Why alert failed? – IT did not fix.
    5. Why not fixed? – No cross-department communication mechanism.Insight: The real problem isn’t “out of stock,” but the lack of cross-department collaboration.
  • Case 2 (Life/Learning)

    Problem: Student scores poorly.

    1. Why poor performance? – Didn’t review.
    2. Why didn’t review? – No study plan.
    3. Why no plan? – Lacks time management.
    4. Why lacks management? – Never learned the skill.
    5. Why not learned? – No guidance from school/family.Insight: The issue isn’t “no review,” but “lack of learning method guidance.”

🌟 Pros & Cons

Pros

  • Easy to apply.
  • Helps teams quickly find root causes.
  • Promotes collaborative problem-solving.

Cons

  • Depends heavily on facilitator’s skills and logic.
  • May not suffice for complex issues—needs tools like Fishbone Diagram.

📌 FAQs

  1. Does it have to be exactly five times?
    • Not necessarily. The key is to reach the root cause—sometimes 3 or 7 iterations are enough.
  2. Can it handle complex problems?
    • Useful as a starting point, but complex issues may require statistical tools or RCA.

📖 Recommended Resources

Books

  • Toyota Production System — Taiichi Ohno, explains 5 Whys in practice.
  • Lean Thinking — James P. Womack, covers continuous improvement principles.

Other Resources

🔗 Related Methods

  • Ishikawa Diagram (Fishbone Diagram)
  • Root Cause Analysis (RCA)
  • PDCA Cycle

🎯 Core Expression

“Ask five whys, reach the essence.”