The Importance of Testing to Locate Root Cause
So far in our Root Cause investigation, we’ve covered the following steps:
Investigation
Comparisons
Clues
Likely cause
The Last Step: Test
Assuming that each of those first five steps have been completed accurately and thoroughly, the test will bring the investigation home, so to speak. Remember how our first three steps were built on facts - just the facts. Clues and likely cause were a combination of expertise and inference. We “connected the dots” and reached logical conclusions.
The Process of Testing
The test forces us to test against the facts - to verify that our intuitions were correct - or not. We ask “if this is the likely root cause, does it explain the Is (investigate) facts and not the Is not (comparison) fact? Yes or No. Then we must justify our answer. If we determine it is yes in each of the four “W’s”, we have probably found our root cause. If we get more than one “no”, we should probably eliminate it as a likely cause.
Challenges
Not conducting a thorough test is often the reason why teams fail at this last step. At this point, teams have done a lot of hard work. You don’t want to quit until you check all your facts. You need to test all likely root causes against all facts.
The Need for Process
Also, often times teams will arrive at this point thinking that one of their likely root causes HAS to be the one. That’s not always the case. You may realize that none of your likely causes fits the facts. That doesn’t mean you failed. As is often the case, your process may highlight where you need more data, or need to go explore more. That’s the beauty of following this process. It can highlight those areas and help you do a more thorough investigation.
Do you have any additional advice to share? If you have had other methods of success in conducting investigations, we’d love to hear about them.
