How to conduct a 5-Why

Mark Galley



Re-thinking how your organization uses 5-Why

With a few minor adjustments, a simple 5-Why can significantly improve the way organizations communicate and solve problems. And knowing how to conduct a 5-Why is crucial. There are different schools of thought about 5-Why. Some organizations adhere to it strictly, others think it provides no benefit. There is opportunity to improve both the understanding and application of this tool. A 5-Why Cause Map is different than what people learned as traditional 5-Why. 

What is 5-Why?

5-Why is a problem-solving tool recognized around the globe. It’s part of six-sigma, lean and Kaizen. The structure is simple. It starts with a problem that gets broken down with a series of Why questions - five of them.   The first question is “Why did the problem happen?” The answer is written down. That answer is the basis of the second Why question. This continues five times. Toyota is credited with establishing 5-Why as a formal method as far back as the 19th century when they made fabric looms. As most of you are aware, exhaustive Why questions were invented by every 3-year-old on the planet. Everyone who has had a child in their life has experienced those Why questions. And, you used to be the 3-year-old asking Why questions to your parents. You already know this.

5-Why purists

There are 5-Why users who believe the fifth Why question provides the “root cause.” It does not. There is no root cause at the end of the 5th Why. Their mental model is that just five Why questions are needed. It seems so perfect, but it’s an illusion. Asking Why questions is an important part of explaining an issue, but there’s no reason to limit the analysis to only five. A 5-Why is a great way to get started, but, depending on the magnitude of the issue, more causes may need to be identified. So, a 5-Why is just a phase of an investigation. It comes after the 4th Why and before the 6th.

Anti-Why crowd

Some individuals and organizations are opposed to Why questions. They believe the question makes people defensive. This simply reveals they don’t know how to use the question. In an investigation, asking “Why did you do that?” may be too pointed, but it’s because of the use of the word “you” - not the question Why.

Some also argue that Why questions are too open ended. They believe the order and structure of an investigation comes from a methodology. It doesn’t. The order is already within the incident. The problem provides the model for explaining it. This is called science. It’s how all things are explained - accurately and thoroughly. Unfortunately, some organizations think problem solving is a combination of different techniques and terminology. They’re ignoring basic principles. They’ve mistakenly made problem solving too complicated in their company. They believe there’s a “secret sauce” for investigating problems. Explaining why the tides move in and out, why hot air rises, why production was delayed, why an injury occurred and why someone gained 15 pounds are the result cause-and-effect. Problem solving methods that change based on type of incident is symptomatic of technique over principle.

"Why" questions are fundamental

A Why question is the easiest way to identify a cause-and-effect relationship. If your organization is interested in meeting goals, preventing problems and making improvements in any area, your people need to learn how to use Why questions. When a 3-year-old asks a Why question we begin our response with “Because.” The root of the word because is cause. Because means “caused by.” Cause-and-effect is fundamental for explaining how and why things happen. There’s no problem solving that happens outside the domain of cause-and-effect. Why a specific solution was effective or how a piece of equipment functions is all explained by cause-and-effect. It’s the basis of all problem solving and troubleshooting. Organizations usually don’t ask enough Why questions within their operations. The ability to ask and answer Why questions is essential for understanding both why things go badly and why they go well. Please let me know why some people think Why questions are not a good idea.

Benefits of 5-Why

Three advantages of building a 5-Why for a problem is that it’s easy to get started, it’s quick to layout and it can be accurate even though it’s basic. A 5-Why is not a complete problem-solving method, but it’s a great way to begin. Why questions break down into cause-and-effect relationships. Regardless of how many causes may be captured within an incident, the investigation can start with 1-Why. It then builds to a 2-Why, a 3-Why and so on. A 5-Why is just a simple first pass. The analysis can expand to a 15-Why, a 25-Why or more, depending on the issue. Remember, a 5-Why is just a phase of an investigation, not a complete method.

 Don’t write sentences

The conventional approach for documenting a 5-Why is sentences written down the page. They’re typically numbered 1 through 5. Sentences are the most time-consuming way to capture a 5-Why. Writing a sentence then asking a Why question and writing down the answer as another sentence takes more words than necessary and creates confusion. Cause-and-effect relationships are much easier to show visually. We suggest building a 5-Why using our Cause Mapping method. Each cause is written in its own box. It lays out horizontally across the page with an arrow pointing from the cause to the effect. Below are several links to some different 5-Why Cause Map examples that you can reference.

The Welding Robot example shows a 5-Why written in sentences using 81-words. The same issue is built in a Cause Map with only 31 words. The visual format is simple, but experiment on some problems in your organization after reviewing the examples or contact me for help.

 5-Why is not supposed to be repeatable

Once of the criticisms of 5-Why is that it’s not repeatable. Different people build different 5-Whys. This criticism reveals how confused people are about the basics of cause-and-effect. Different people naturally build different 5-Whys. People don’t see problems the same way - they have different backgrounds and areas of expertise. Some argue that 5-Why is not scientific because it’s not repeatable. That statement is flawed. A thorough analysis, for example with 15 causes, will be repeatable, but everyone doesn’t see the same 5 causes within that issue. Three people can provide three different 5-Whys that all combine to into one more complete explanation of the issue. If each 5-Why is built accurately, they’ll combine without any contradiction. It’s much easier to demonstrate using an example Cause Map. The Titanic 5-Why shows how 3 different 5-Whys build into one 9-Why Cause Map. This works precisely because of cause-and-effect.

 Improving the improvement tool

Expanding an analysis beyond a 5-Why is simple, but it’s not well understood. Most 5-Why users have been taught to restrict a problem analysis to only five questions. Starting an investigation as a 5-Why is smart. Limiting it to a 5-Why is not. It’s another example of how a prescriptive method alters the explanation. Your problem-solving method should not distort the issue. It should reflect it. A map of your town should look like your town. A map of your problem should look like the issue – regardless of what level of detail you reveal – 5, 15 or 25 causes. All the Cause Maps are accurate, they’re just at different levels of detail. Don’t limit the clear explanation of your problems. Experiment with this approach on some problems in your company.

 Here's an example

Watch this short video on how to conduct a 5-Why using our very popular case study of the sinking of the Titanic.

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