Asking “Why?” isn't just something your three-year-old child does to drive you crazy it could also teach you a valuable quality improvement lesson.
The 5 Why’s is a technique used in determining the root cause of a problem and can be used during any improvement effort, including during the Analyze phase of the Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) methodology.
Repeatedly asking the question “Why” (five is a good rule of thumb), can peel away the layers leading to the root cause of a problem. Very often the answer to the question “why” will lead you to another question.
Although this technique is called “5 Why’s,” you may find that you'll need to ask the question fewer or even more times than five before you find the base issue related to a problem.
How to Complete the 5 Whys
1. Write down the specific problem. Although writing the issue down is not required, it helps you formalize the problem and describe it completely, it also helps a team focus on the same problem
2. Ask why the problem happens and write the answer down below the problem. A written response serves the same focusing purposes
3. If the answer you just provided doesn’t identify the root cause of the problem that you wrote down in Step 1, ask why again and write that answer down
4. Repeat step 3 until the team agrees that the problem’s root cause is identified. Again, this may take fewer or more times than 5 Whys.
Best 5 Why’s Example The national park service was over budget on a regular basis so they called in some consultants. The consultants held a meeting in which they started asking why?
Q. Why is the park service regularly over budget?
A. Because resurfacing the Jefferson Memorial has to be done more frequently than anticipated.
Q. Why does the Jefferson memorial have to be resurfaced so often?
A. Because it has to be power washed weekly and the surface of the monument is damaged.
Q. Why does it have to be power washed weekly?
A. Because it collects excessive bird droppings.
Q. Why does it collect excessive bird droppings?
A. Because the birds are always there.
Q. Why are the birds always there?
A. They like to eat the spiders that are in abundance.
Q. Why are the spiders in abundance?
A. They like to eat a small fly like creature called a midge that swarm around the memorial in the evening.
Q. Why do the midges swarm around the memorial in the evening?
A. They are attracted to the lights on the memorial and the Jefferson memorial turns on it lights earlier than other memorials.
So it turns out that the solution being over budget so frequently, was to turn the lights on a little bit later in the evening.