One standard method of Lean to find root causes of a problem is the “5 Why” method. It is quite simple:
Let us look at an exaggerated example. The symptom I want to start with is the classical joke about the chicken crossing the road. As you can see, even seemingly trivial starting points can lead to severe underlying root causes.
- Question: Why did the chicken cross the road? Answer: Because the gate was open.
- Q: Why was the fence open? A: Because the farmer did not close it in the evening.
- Q: Why did the farmer forget to close the gate? A: Because he was drunk.
- Q: Why was the farmer drunk? A: Because his wife had left him.
- Q: Why did his wife leave him? A: Because he is an alcoholic.
You see the pattern: Rephrase each answer to a “why” question as a new why question until you reach an answer which reveals a real issue. The method is called “5 Why”, because usually around the fifths time you ask you get a good answer. In general somewhere between the fourth and the sevenths answer some truth will show up. Actually, in my example, the answer number 3 was already a good one. Number 5 is just a kind of rephrasing the earlier answer. This is also a good indicator for a root cause: When answers start to circle around the same issue, you are near the root.
My example may have started with a funny line, but it is meant serious. It is not uncommon that minor matters in one’s life have a root cause which is a lot bigger. Would you have accepted the shortcut? As a cross-check replace the chicken incident by something more usual.
Side remark: No, I don’t have any prejudices against farmers and alcoholism. Starting with the classical “Why did the chicken cross the road?” it was just one way to create such a chain. It could have been the postman in a hurry or a child who drove on a bicycle and therefore forgot to close the fence. Or somebody else…