“The basis of Toyota’s scientific approach is to ask why five times whenever we find a problem … By repeating why five times, the nature of the problem as well as its solution becomes clear.” Taiichi Ohno
The 5 Whys method, part of the Toyota Production System and developed by Sakichi Toyoda, is a seemingly simple technique (rooted in Lean philosophy) that can have powerful impacts on the way that teams and businesses function. By asking "why" at least five times, teams move beyond surface-level issues to uncover the root cause of a problem (or opportunity), enabling more effective, lasting solutions. Note that teams can also ask how, what, when, where.
Success with this method relies on curiosity, open-mindedness and a blame-free environment, remembering that most problems are more complex than they might initially seem. Key foundations include documenting relevant facts, involving all subject matter experts and having an experienced facilitator. In general, teams should stop when the answer is ‘we don’t know’ to avoid making incorrect assumptions.
Here are 4 situations where this method can be applied. Some may surprise you!
#1. Determining the root cause of an incident
This one is not so surprising. Many organizations use this method to identify the root cause of incidents. Often starting with a simple problem statement such as “Our system was down for 2 hours” and asking why that happened five times can prove truly enlightening.
Of course a common challenge is that incident root causes can be very complex, for example architectural or technological constraints. Having experienced facilitators as well as someone responsible for tracking patterns across teams over time can help identify recurring occurrences of the same root cause, so that those can be brought to the attention of key decision makers. Addressing these types of issues could involve forming a task force to discuss the most pragmatic way to solve the problem or reduce the impact in future. Solving the problem may require an investment of time from the organization.
To support that business case, it's crucial to keep in mind that solving root causes not only prevents future issues but also immediately increases capacity by reducing reactive work.
#2. Understanding what is slowing a team down
Cross-functional teams struggling to find flow or improve velocity can run 5 Whys exercises to identify improvement opportunities. For example, starting with a problem statement such as “This ticket took 7 days to be deployed” and asking why that occurred. This can be particularly effective at team level because in theory improvements identified should be within their control to action.
In some cases a 5 Why's exercise may highlight cross-team dependencies, sparking broader initiatives for improvement.
#3. Determining the best solution to build
Feature development teams can apply the 5 Whys method proactively to uncover the best solutions to build for customers by exploring the difference between what customers are asking for - and what they might actually need. At the very least it can help with prioritizing the work.
For example a problem statement such as: “Customers are requesting a way to do X.” The team can then ask, “Why do they need that?”- digging deeper with each answer to ensure they’re solving the right problem. Note in this case it will be crucial to involve someone with a deep understanding of the customer experience or ideally asking customers directly.
#4. Iterating on a customer facing experiment
When teams are running experiments and need to decide whether to tweak or pivot on their approach, a 5 Whys exercise can help uncover the best path forward.
For example a problem statement such as: “Customers aren’t using the new feature A.” By asking “Why?” repeatedly, teams might discover they are targeting the wrong audience, have an insufficient sample size or that there are UX challenges. They may even discover they have been solving the wrong problem!
As The Lean Startup suggests, fully embracing this approach allows teams to quickly learn, adapt, and iterate. As a result, it has the power to transform experiments and ideas that were deeply flawed at the outset into valuable outcomes.