What Are the "5 Whys"?
The "5 Whys" is a straightforward but powerful problem-solving strategy. It seeks to uncover the true source of a problem by repeatedly asking “why”—usually five times—until you reach the fundamental cause.
In practice, you begin by asking “why” the problem occurred. Each time you find a new explanation, you ask “why” again. This process continues until you’re confident you’ve revealed the underlying reason behind the issue. If this technique sounds a little familiar, you've probably seen it before as a part of the Scientific Method. The "5 Whys" isn't that exhaustive or time-consuming, but is a very popular quick troubleshooting technique.
Why Use the 5 Whys?
By going beyond surface-level symptoms, the 5 Whys helps you identify the real root cause. Once you focus on what truly triggered the issue, you can devise a more effective and lasting solution—one that reduces the risk of the problem returning.
Origins of the 5 Whys
This technique is often linked to Sakichi Toyoda, the founder of Toyota Industries. It became a key part of the Toyota Production System (TPS), widely known for its commitment to continuous improvement. Although rooted in manufacturing, the 5 Whys has proven valuable in many different fields.
Example of the 5 Whys In Action
Problem:
The production line stopped working.
Why Questions:
Why did the production line stop?
Because the machine was overheated.
Why did the machine overheat?
Because the cooling system failed.
Why did the cooling system fail?
Because the pump stopped working.
Why did the pump stop working?
Because it wasn’t maintained regularly.
Why wasn’t the pump maintained regularly?
Because there wasn’t a scheduled maintenance plan in place.
In this example, asking "Why" several times allows the team to identify root cause-of the production line stopping. The lack of a maintenance plan is identified and addressed as root cause. So this particular issue with the production line should now be preventable in the future. In IT and DevOps work, this is a great troubleshooting method; however, it also comes in handy for any Project dealing with product or process issues that come-up. So Project Managers might use it with the team, to work out major issues before they impact any deliverables.
Benefits of the 5 Whys
- Identifies Root Causes
By persisting with “why,” you can move past superficial fixes and locate the core factors driving the problem. - Encourages Critical Thinking
The repetitive questioning challenges assumptions and compels teams to think more deeply about interrelated factors. - Simple and Cost-Effective
The 5 Whys doesn’t require specialized tools or extensive training. It’s an easy-to-implement method suitable for organizations of any size.
Keep in mind that “five” is not set in stone—sometimes you’ll reach the root cause in fewer steps, or sometimes you may need more. The goal is simply to continue asking “why” until you’re confident you’ve arrived at a clear root cause and actionable solution.