The 5 Whys Method of Root Cause Analysis
This topic is provided by http://www.isixsigma.com/library/
It’s important when resolving a problem that you address the problem and not a symptom of the problem. Determining the real problem is called finding the root cause. There are special techniques for determining the root cause of a problem. One technique is known as “The 5 Whys.”
Keywords: failure mode, failure analysis
What Is It?
The five whys is a form of root cause analysis. You start with a statement of the situation and ask yourself why it is happening. Then you look at your answer and ask “Why” again and again until you have done so five times. By refusing to be satisfied with just one explanation, you increase the possibility of identifying the root cause of the situation.
How does it work?
After describing the situation. You ask yourself why that situation is occurring and enter your response in the appropriate space in the tool. You then look at your first answer and ask yourself why that situation is occurring. You do this again and again until you have asked why five times or until you can no longer answer the why question.
When would I use it?
Very often, the real cause of a problem or situation is not obvious. The obvious explanation often reveals yet another problem. The five whys is very helpful in such situations.
By repeatedly asking the question “Why” (five is a good rule of thumb), you can peel away the layers of symptoms which can lead to the root cause of a problem. Very often the ostensible reason for a problem will lead you to another question. Although this technique is called “5 Whys,” you may find that you will need to ask the question fewer or more times than five before you find the issue related to a problem.
Benefits Of The 5 Whys
Help identify the root cause of a problem. Determine the relationship between different root causes of a problem. One of the simplest tools; easy to complete without statistical analysis.
When Is 5 Whys Most Useful?
When problems involve human factors or interactions. In day-to-day business life; can be used within or without a Six Sigma project.
How To Complete The 5 Whys
- Write down the specific problem. Writing the issue helps you formalize the problem and describe it completely. It also helps a team focus on the same problem.
- Ask Why the problem happens and write the answer down below the problem.
- 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.
- Loop back to step 3 until the team is in agreement that the problem’s root cause is identified. Again, this may take fewer or more times than five Whys.
Problem Statement: You are on your way home from work and your car stops in the middle of the road.
1. Why did your car stop?
– Because it ran out of gas.
2. Why did it run out of gas?
– Because I didn’t buy any gas on my way to work.
3. Why didn’t you buy any gas this morning?
– Because I didn’t have any money.
4. Why didn’t you have any money?
– Because I lost it all last night in a poker game.
5. Why did you lose your money in last night’s poker game? – Because I’m not very good at “bluffing” when I don’t have a good hand.
As you can see, in both examples the final Why leads the team to a statement (root cause) that the team can take action upon. It is much quicker to come up with a system that keeps the sales director updated on recent sales or teach a person to “bluff” a hand than it is to try to directly solve the stated problems above without further investigation.