There is a simple but effective technique for determining the root cause without resorting to the more complex tools and techniques included in the Analyse section of the Six Sigma DMAIC methodology - covered in depth on our Root Cause Analysis course as well as our Lean Six Sigma Green Belt, Black Belt & Yellow Belt courses:
The 5 Whys
A question every parent and teacher will be very familiar with, asking why is a great way of winding people up. Every time you ask why, someone has to explain the last reason they gave - narrowing down or opening up the original statement until the asker is happy - which can go on for a long time with children.
What makes asking why a workable solution for determining the root cause of a problem?
- It is an easy tool that requires little statistical analysis
- You document each step of the analysis so you always know the path to the root cause
- The root cause is found more often that not
- Multiple root causes are often stumbled upon during the process
Why 5?
5 has been identified as the optimum number of ways needed to find the root cause of a problem. Most root causes are identified around the 5th question but some more complex problems lead to more questions being asked.
Andy Trainer
25 May 2012