The "Five Whys"
You may be aware of a technique called The Five Whys. This technique is often used in Root Cause Analysis and in Six Sigma.
The gist of the technique is to ask “why” five times and that (supposedly) leads you to a Failure Mode that is written at just the right level so that an appropriate Failure Management Strategy can be developed.
Recall from our module on Failure Modes that a Failure Mode is like a road. Properly written Failure Modes allow us to reach our “destination” (aka technically appropriate maintenance tasks and intervals and Default Strategies).
Back to The Five Whys.
Here’s what my mentor John Moubray had to say about The Five Whys. (I remember like it was yesterday. During my RCM Practitioner training, John stood in his stocking feet and taught us that The Five Whys is “a bunch of rubbish.”) Here’s how he explained it to us.
Let’s start with the Failure Mode "Bearing Seizes.” Obviously “Bearing Seizes” is written at too high a level for us to formulate any meaningful solutions. So, let’s ask “why” five times.