Easy question. ‘5 whys’.
5 Whys was first articulated by Toyota’s architect of the TPS, Taiichi Ohno in the 50’s, but it was not new.
Anyone who has had children has been on the receiving end of a form of the ‘5 whys’ from about two and a half years old, to 6 or 7, by which time they have learnt that the question is not always appreciated or answered fully, so they stop asking.
The process is deceptively simple, keep asking ‘Why’ until you get to the root cause of the problem, well past the symptoms, so it can be fixed, and the problem not recur.
In a previous life managing a manufacturing business, we had a recurring problem with an automatic box erector that seemed intractable despite huge efforts. The whole line stopped every time the erector spat the dummy, causing serious production losses.
While it took months to find the right cause, after chasing a lot of rabbits down holes, we finally nailed it using 5 why.
- Why did the erector jam?
One of the arms was out of alignment to the flat box
- Why was the arm out of alignment?
One of the flat box ends was slightly crooked
- Why was the box end crooked?
The box end was slightly out of specification
- Why was the box end out of specification?
The purchasing manager had changed suppliers for a significant saving, and the new suppliers actual operational control allowed variations outside the erectors demanding requirements, resulting in an occasional mechanised ‘dummy-spit’.
This example in fact only took us ‘4 whys,’ but the trick was to ask the right questions in the first place, in the right sequence. This took us several months and cost a huge amount in lost production, and maintenance resources as we eliminated possible causes of the problem before anyone thought to examine if a 1 mm variation outside the spec of the flat box size was significant.
Once identified that it was, the problem was quickly fixed by moving back to the previous supplier with whom we had encountered no problems.
Subsequently, we evolved a process that used 5 whys as a matter of course in search of improvements in the factory, and later, admin processes, and found that our problem resolution times dropped dramatically.
The process is pretty simple, just challenging to implement:
- Institute a ‘5 whys’ meeting in response to a problem.
- Invite (read insist) everyone involved and/or affected by the problem to attend the meeting.
- Agree a ‘chairman’ for the problem who will take overall responsibility.
- Proceed to ask ‘Why’ until you get to the root cause of the issue. It almost never takes more than 5 ‘whys’ hence the name. This step can take time and often takes several meetings as possible answers to the ‘why’ are considered.
- Assign responsibility to install, test and validate the solution
- Document and disseminate the solution which has been broken into a written process to ensure compliance, or easier further investigation should a similar problem arise.
The whole objective is to get to the root cause of the problem, a process that is applicable not just in industry, but in your life, when you think about it.
Diagram courtesy Mindtools.com
