Six Sigma Quality Resources for Achieving Six Sigma Results
Click To Learn More About PremiumLinks
 Home > Tools & Templates  > Cause & Effect (Fishbone, Ishikawa) Search:
 
 for    
Publications
Marketplace
| iSixSigma
Stuff
| iSixSigma
Blogosphere
| Events
Calendar
| The
Dictionary
| Discussion
Forum
| Find
a Job
| Post
a Job
| Industry
News
| Newsletter
Signup
| Sigma
Calculator
| Online
Surveys
DMAIC 2009 Training Slides: 1,220 PPT Slides + Instructor Notes and More for $99.95
iSixSigma Magazine Signup
 iSixSigma Live!  
  2010 Summit & Awards
  2010 Energy Forum
 Free Newsletters!  
  Sign Up Now!
  Manage Subscriptions
  New To Six Sigma?
  Six Sigma Q&A
  Cert. Practice Test
  Problem Solving Wizard
  ISSSP Info
ISSSP Is The Official Six Sigma Society of iSixSigma
 Channels 
  Europe
  Financial Services
  Healthcare
  Military
  Software / IT
 Quality Directory 
  Best Practices
  Certifications/Awards
  Consultants
  Culture Evolution
  Methodologies
  News & Events
  Organizations
  Product/Service Guides
  Statistics & Analysis
  Tools & Templates
   DOE
   FMEA
   Glossary
   Histogram
   Pareto
   Poka Yoke
   SIPOC
   Software
  Voice of the Customer
  Free Whitepapers
 Related Topics 
  Innovation
  Outsourcing/Offshoring
  Business Process Mgt
 Quick Access 
  Help
  Search
  Advertise Here
  Article Archives
  Newsletter Archives
 User Feedback 
  Please suggest site
  improvements.
 
  [ larger form ]

Determine The Root Cause: 5 Whys

Bookmark This Page Bookmark This Page
Email This Page Email This Page
Format for Printing Format for Printing
Cite This Article Cite This Article
Submit an Article Submit an Article
Six Sigma Article Archive Read More Articles
Related Tools & Articles
  • Discussion Forum
    "I am working on a Six Sigma project and we found a measure within our scope is a critical X. We need to know what caused this X to vary before we venture into Improve. Our process is very long and complex, and after 4 weeks of continued investigating the upstream root causes of this critical X, we aren't even near explaining 95% of it. When and how do you pull the plug on extra-scopic Analyze activities so that you can move on the measured X and make your improvement?"
    Root Cause In Analyze
    Download Products

    Asking "Why?" may be a favorite technique of your three year old child in driving you crazy, but it could teach you a valuable Six Sigma quality lesson. The 5 Whys is a technique used in the Analyze phase of the Six Sigma DMAIC methodology. It's a great Six Sigma tool that doesn't involve data segmentation, hypothesis testing, regression or other advanced statistical tools, and in many cases can be completed without a data collection plan.

    By repeatedly asking the question "Why" (five is a good rule of thumb), you can peel away the layers of symptoms which can lead to the root cause of a problem. Very often the ostensible reason for a problem will lead you to another question. Although this technique is called "5 Whys," you may find that you will need to ask the question fewer or more times than five before you find the issue related to a problem.

    Benefits Of The 5 Whys

  • Help identify the root cause of a problem.
  • Determine the relationship between different root causes of a problem.
  • One of the simplest tools; easy to complete without statistical analysis.

    When Is 5 Whys Most Useful?

  • When problems involve human factors or interactions.
  • In day-to-day business life; can be used within or without a Six Sigma project.

    How To Complete The 5 Whys
    1. Write down the specific problem. Writing the issue helps you formalize the problem and describe it completely. It also helps a team focus on the same problem.
    2. Ask Why the problem happens and write the answer down below the problem.
    3. If the answer you just provided doesn't identify the root cause of the problem that you wrote down in step 1, ask Why again and write that answer down.
    4. Loop back to step 3 until the team is in agreement that the problem's root cause is identified. Again, this may take fewer or more times than five Whys.

    5 Whys Examples
    Problem Statement: Customers are unhappy because they are being shipped products that don't meet their specifications.
    1. Why are customers being shipped bad products?
      - Because manufacturing built the products to a specification that is different from what the customer and the sales person agreed to.
    2. Why did manufacturing build the products to a different specification than that of sales?
      - Because the sales person expedites work on the shop floor by calling the head of manufacturing directly to begin work. An error happened when the specifications were being communicated or written down.
    3. Why does the sales person call the head of manufacturing directly to start work instead of following the procedure established in the company?
      - Because the "start work" form requires the sales director's approval before work can begin and slows the manufacturing process (or stops it when the director is out of the office).
    4. Why does the form contain an approval for the sales director?
      - Because the sales director needs to be continually updated on sales for discussions with the CEO.

    In this case only four Whys were required to find out that a non-value added signature authority is helping to cause a process breakdown.

    Let's take a look at a slightly more humorous example modified from Marc R.'s posting of 5 Whys in the iSixSigma Dictionary.

    Problem Statement: You are on your way home from work and your car stops in the middle of the road.
    1. Why did your car stop?
      - Because it ran out of gas.
    2. Why did it run out of gas?
      - Because I didn't buy any gas on my way to work.
    3. Why didn't you buy any gas this morning?
      - Because I didn't have any money.
    4. Why didn't you have any money?
      - Because I lost it all last night in a poker game.
    5. Why did you lose your money in last night's poker game?
      - Because I'm not very good at "bluffing" when I don't have a good hand.

    As you can see, in both examples the final Why leads the team to a statement (root cause) that the team can take action upon. It is much quicker to come up with a system that keeps the sales director updated on recent sales or teach a person to "bluff" a hand than it is to try to directly solve the stated problems above without further investigation.

    5 Whys And The Fishbone Diagram
    The 5 Whys can be used individually or as a part of the fishbone (also known as the cause and effect or Ishikawa) diagram. The fishbone diagram helps you explore all potential or real causes that result in a single defect or failure. Once all inputs are established on the fishbone, you can use the 5 Whys technique to drill down to the root causes.

    Take-Away Quotation
    "If you don't ask the right questions, you don't get the right answers. A question asked in the right way often points to its own answer. Asking questions is the ABC of diagnosis. Only the inquiring mind solves problems." -- Edward Hodnett

     
    Rate This Article:  Current Rating: 4.33
      Poor    Excellent     
              1    2    3     4    5
    Copyright � 2000-2009 iSixSigma – All Rights Reserved
    Reproduction Without Permission Is Strictly Prohibited – Copyright Requests


    Publish an Article: Do you have a Six Sigma tip, learning or case study?
    Share it with the largest community of Six Sigma professionals, and be recognized by your peers.
    It's a great way to promote your expertise and/or build your resume. Read more about submitting an article.




    "The Bottom Line" Links

    BEST SELLING PRODUCTS (iSixSigma Publications)
    1. Six Sigma Black Belt (DMAIC) Training Slides - 2009 Version!
      The 2009 Six Sigma Black Belt course includes over 40 more slides than the 2008 version. Contents include: 1,220 PowerPo...
    2. Certified Lean Six Sigma Black Belt Assessment Exam
      Interested in assessing your knowledge of Lean Six Sigma? Preparing for certifications? Testing your students and traine...
    3. Certified Lean Six Sigma Green Belt Assessment Exam
      This assessment exam is useful for students interested in assessing their knowledge of Lean Six Sigma on the Green Belt ...
    4. Kaizen Workshop E-book
      This 150+ page ebook teaches key tools and techniques of Kaizen, as well as real application to enhance learning. Kaizen...
    5. Certified Lean Six Sigma Black Belt E-book
      In 670 pages learn everything within the Lean Six Sigma DMAIC body of knowledge to successfully achieve Black Belt certi...
    6. Process Management Training Slides
      The 2008 Process Management course is designed in two phases comprised of:352 Powerpoint slidesInstructor notesSlide exp...
    7. Design For Six Sigma (DFSS) E-Book or Print
      Need an "encyclopedia" consisting of many of the tools you’ll study? Need a helpful refresher to apply the DFSS process?...
     
  • Six Sigma AdLinks
    AdLinks Information


    Google AdWords
     
    Home | Discussion Forum | Event Calendar | Job Shop
    Link To iSixSigma | Rate This Page | Report A Problem | Free Content For Your Site | Submit Article For Publishing
     Terms of Service. �2000-2009 iSixSigma. All rights reserved. v3.0lb, 0.1
    About iSixSigmaContact UsPrivacy PolicySite Map