My car broke down recently and I was stuck by the side of the road waiting for a recovery company. It gave me an opportunity to watch a real expert in root cause analysis at work.
He started by ascertaining exactly what the problem was – the car had just been parked and would now not start. He then went into a series of questions. How much had the car been driven that day? Was there any history of the car not starting or being difficult to start? Next he was clearly thinking of the process of how a car starts up – the electrics of turning the motor, drawing fuel into the engine, spark plugs igniting the fuel, pistons moving and the engine idling. He started at the beginning of the process. Could the immobiliser be faulty? Had I dropped the key? No. Maybe the battery was not providing enough power. So he attached a booster – but to no avail. What about the fuel? Maybe it had run out? But the gauge showed ½ tank – had I filled it recently? After all the gauge might be faulty. Yes, I had filled it that day. Maybe the fuel wasn’t getting to the engine – so he tapped the fuel pipe to try to clear any blockage. No. Then he removed the fuel pipe and hey presto, no fuel was coming through. It was a faulty fuel pump. And must have just failed. This all took about 10 minutes.
The mechanic was demonstrating very effective root cause analysis. It’s what he does every day. Without thinking about how to do it. I asked him whether he had come across “Five Whys” – no he hadn’t. And as I thought about Five Whys with this problem, I wondered how he might have gone about it. Why has the car stopped? Because it will not start. Why will the car not start? Erm. Don’t know. Without gathering information about the problem he would not be able to get to root cause.
Contrast the Five Whys approach with the DIGR® method:
Define – the car will not start
Is/Is not – the problem has just happened. No evidence of a problem earlier.
Go step-by-step – Starter motor, battery, immobiliser, fuel, spark plugs.
Root cause – He went through all the DIGR® steps and it was when going through the process step-by-step that he discovered the cause. He had various ideas en route and tested them until he found the cause. He could have kept going of course – why did the fuel pump fail? But he had gone far enough, to a cause he had control over and could fix.
Of course, he hadn’t heard of DIGR® and didn’t need it. But he was following the steps. In clinical trials, there is often not a physical process we can see and testing our ideas may not be quite so easy. But we can still follow the same basic steps to get to a root cause we can act on.
If you don’t carry out root cause analysis every day like this mechanic, perhaps DIGR® can help remind you the key steps you should take. If you’re interested in finding out more, please feel free to contact me.
Photo: Craig Sunter (License)
Text: © 2017 Dorricott MPI Ltd. All rights reserved.
DIGR® is a registered trademark of Dorricott Metrics & Process Improvement Ltd.