ASQ 415 Windsor Section March 24th, 2016 Tech Talk – Gulten Ozaltan

The 5 Whys The “5 Why’s?” is the most basic form of Root Cause Analysis It is used in the Analyze phase of the Six Sigma DMAIC methodology

The 5 Whys Does not involve advanced statistical tools such as data segmentation, hypothesis testing, regression and in many cases can be completed without a data collection plan We peel away the symptoms to identify root causes It is Simple: Ask “why?” until you can’t ask “why?” anymore

The origin of the 5 Whys “by repeating why five times, the nature of the problem as well as its solution becomes clear.” “Observe the production floor without preconceptions. Ask ‘why’ five times about every matter.” Taiichi Ohno, Inventor of the Toyota Production System (TPS)

The 5 Whys – Key areas “Why it is Made? “ - The process made the defective part “Why it is Not Detected?” – The Detection system failed to catch the nonconformity “Systemic Cause” – The system allowed problem to occur

The 5 Whys – Who to invite for how long? Individuals who know about the product and/or process at hand Complete in one session, no more than an hour long

How to Complete the 5 Whys Write down the specific problem. Ask Why the problem happens and write the answer down below the problem. 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. Loop back to step 3 until the team is in agreement that the problem’s root cause is identified.

5 Whys Story Solution: Turn the lights on 30 minutes later! Problem: The Washington Monument was falling apart Why? Because harsh chemicals were used to clean it. Why? Because of all the bird droppings. Why? Because birds feasted on all the spiders there. Why? Because spiders feasted on all the gnats there. Why? Because gnats were attracted to the lights at dusk. Why? Because the monument was 1st to turn its lights on. Solution: Turn the lights on 30 minutes later! Result: 90% reduction in the number of gnats within 2 weeks.

answers to the why’s tend to lose focus on the third or fourth why. For all the 5 Whys Ask the full question including the problem or cause behind it. If there is a problem with labeling ask: “Why the parts were labeled incorrectly?” OTHERWISE answers to the why’s tend to lose focus on the third or fourth why.

The 5 Whys – Conclusion A good way to identify if the 5 Why’s was done properly is to try to organize the collected data in one sentence and define it in an understandable manner. You then must revisit the 5 Why and identify those gaps to fill them in. REMEMBER If you do reproduce problem, move on to the Corrective Action part and congratulate your team for a job well done. A PROBLEM THAT CANNOT BE REPRODUCED IS A PROBLEM THAT HAS NOT BEEN RESOLVED YET.

Questions?