The Quality Blog

I was returning a car the other day at Hetrz at the Detroit airport. And lo and behold on the wall upstairs were large poster sized examples of how to do an 8D. 8D as you know is a great way to get to a root cause of a problem by working it from the Symptom to the Problem Statement using the 5 why process. From there the statement is converted to a problem description using an IS/IS NOT analysis. The IS/IS NOT gathers facts about the what, where, when and How Big. This analysis is more about finding out what the problem is not as opposed to looking for the root cause initially.

The Root cause is only agreed upon after developing theories based on the facts and the Differences and changes that have taken place. Change is usually where the problem is. The fact that change takes place without proper verification and validation makes the 8D process very effective. The team does not have to be Six Sigma experts to use it effectively, but it ties in nicely with six sigma process.

I hope Hertz uses the process effectively and I wish them good luck and applaud the effort to find the root cause and fix it at that level.

Just another note on the 8D relationship to the FMEA, I am sitting in a facilitation of the Lean FMEA approach and one of the matrix items is the 8D imputs. The past failures is one item in the 3 cases for doing an FMEA.

The  FMEA and more appropriately the Lean design Matrix for the FMEA family should always be present for the 8D development. The brainstormed causes already present in the FMEA can shorten the root cause activity by at least one and possibly two layers of the “WHY” discussions.

Keep in mind that the FMEA will be updated at D7 (prevention) or if done most efficiently in real time at D2 and D4 as the 8D progresses.

Lee

8D or Eight Disciplines for Problem Solving uses many of the most common tools for developing a path to get to the Root Cause. 8D does have one intersting characteristic. The 8D uses the IS/IS NOT exercise to gather facts and do comparative analysis for the purpose of determining where the root cause is not. Let me repaet that. The 8D process attempts to gather facts to prove where the problem is not. After sufficient facts have been gathered the possible causes are eliminated by proving they are not the root cause. This is typically not understood when using 8D as most people are trying to find the root cause directly instead of finding out what it is not.

In Canada this week and boy is it cold. I was teaching an 8D class with the Global 8D Ford twist. While teaching we got into a discussion on the FMEA relationship to the 8D. My response was that these two processes are one in the same except FMEA is an 8D that we do before the need for an 8D. The FMEA Failure Mode corresponds to the problem statement and description on the 8D. The effects of failure in the FMEA and customer symptom in 8D are related and the causes in the FMEA are the possible causes and the most likely causes in 8D. The MLC have higher Occurrence ratings. The FMEA is usually related to the D7 (prevention) step but I want you to take a look at the FMEA at the D4 step just to see the legacy of causes already captured from the FMEA. Updating the FMEA is also a way to assure that the 8D talks to the FMEA. If you would like more on this topic please write me or comment or go to www.quality-one.com