Test your assumptions with the Five Whys

Get to the core of a problem by asking ‘why’ no fewer than five times.

The ‘Five Whys’ is an analytical process created by Sakichi Toyoda - Japanese industrialist, inventor and co-founder of Toyota Motor Company. It was originally used to analyze issues related to the manufacturing setting.

However, this simple process has been generalized and applied to non-manufacturing situations which require digging deeper to find the core of an issue, such as simple problem solving, troubleshooting and quality improvement. It is also the prototype behind the more detailed evaluation tool called Fishbone or Cause Effect Analysis (Karoru Ishikawa).

The first step of this process is to define the problem and then the second step is to continue to ask ‘why’ until the core of the problem has been discovered, at which point an action plan can be identified. The following example demonstrates this process:

Defined Problem - The interior of the office microwave is consistently dirty

  1. Why is the interior of the microwave consistently dirty? Because it is not cleaned after being used.
  2. Why it is it not cleaned after being used? Because the users do not know, do not care or have not been asked to clean it after using it.
  3. Why do the users not know, not care or have not been asked to clean it after using it? Because it wasn’t recognized as a problem before.
  4. Why wasn’t it recognized as a problem before? Because the microwave is a recent addition to the office break room.
  5. Why was the microwave a recent addition to the office break room? Because staff asked for a microwave so they could heat food during their breaks.

In this simple example, the root cause of the microwave problem was discovered to be people who use the new microwave do not clean it after using it. The solution or action plan is to request all users clean the microwave after each use.

In any case, Michigan State University Extension says that using this method will help to discover the root cause of an issue, dispel misperceptions surrounding the issue and move toward an action plan to resolve the issue. The Five Whys is a useful model that is easy, practical and can, rather quickly, help identify the root of a problem.

Nonetheless, there are drawbacks to this process, foremost is that constantly asking ‘why’ can be intimidating and seem threatening, especially in groups when individual perspectives are at play. Therefore, it might be helpful when in a group to establish ground rules, similar to brainstorming; making clear that this process is an exploration of ideas with a focus on finding a resolution for a problem, not a finger-pointing or fault-finding exposition. When a more detailed and deeper analysis of an issue is required, the Fishbone or another analytical tool may be more appropriate.

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