The Five Whys Technique...An Overview
One of the fastest ways to determine the root cause of any problem is by asking the right questions. Not all questions produce the right answer. But if you ask enough of the right questions, you have a better chance of success. One method to asking the right questions is the 5 Whys Technique.
The 5 Whys Technique was developed by the Toyota Motor Corporation as a critical component of its training program to help workers solve problems. This technique encourages workers to dig into each problem until an answer is found through identification of the root cause. It is an incremental, easy-to-learn method that also equips workers with the tools to prevent the same problem from happening in the future.
Finding the Root of the Problem
The idea behind the 5 Whys technique is simple: find the root cause of a problem by asking “why” questions. The first “why” question should lead to a second “why” question, which should lead to a third “why” question, which should lead to a fourth “why” question, which should lead to a fifth “why” question, which should lead to the cause of the problem, which should lead to the answer to the problem. For example, you are trying to drive somewhere and your car won’t start. The 5 Whys technique in action is below:
- Why won't the car start? - Answer: The battery is dead
- Why is the battery dead? - Answer: The alternator is not working properly
- Why isn't the alternator working? - Answer: The serpentine belt has broken
- Why did the serpentine belt break? - Answer: It was not replaced when worn
- Why wasn't it replaced? - Answer: The owner did not follow the recommended service schedule
The 5 Whys technique often results in unexpected answers. Issues that were initially believed to be a technical problem might actually turn out to be a human or process problem. In the above example, the original problem is a car that won’t start. The 5 Whys technique led to the root cause of not following the recommended service schedule. As a result, if the owner follows the service schedule, this same problem is unlikely to occur again in the future.
Why Five Why?
While the 5 Whys technique has limitations, it can be used as a starting point to find one root cause of a complex problem, which can lead to determining other root causes. Regardless of the problem-solving technique, finding and eliminating the root cause of a problem is critical to working safely through accident prevention.