Root Cause Analysis

I wanted to say a few words on this topic since I was recently asked about my views on root cause.  How do  I go about doing a root cause analysis in a food manufacturing facility?  To begin - there is an issue (non-conformance) that you or a co-worker has spotted.  From here there are two methods that I use, the 5 whys and the fishbone/Ishikawa diagram.

Either method can lead you to the root cause but I have found using both together creates a more coherent and structured process.  I start with data collection, to know what I am challenged with. The who - what - where - when - why - how questions.  Then using the fishbone I (or a group) can go thru a process / procedure and identify all the elements that effect and influence it.  A sample is below.  This will help organise your thoughts.

From here I will ask the "5 whys" keeping in mind the causes that were brainstormed in the fishbone.  The idea here is, by the time that you have gotten to the fifth level of asking why - you are at the true root cause.  Using this simple and powerful method lessens the "knee jerk" reactions to what caused the issue.  Often the answer is not as evident as you may think. Sometimes less or more why questions will need to be asked.

You are not done, however, the issue needs to be corrected.  The root cause needs to be documented and an action plan put into motion with a defined time for completion.  Followed by a verification of the completed correction to make sure it was effective.

Thanks

Michael Perz.