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Methods5 Whys
DiscoveryProblem DiscoveryQualitative ResearchBeginner

5 Whys

Uncover the root cause of recurring problems by iteratively questioning surface-level symptoms and assumptions.

The 5 Whys is a root cause analysis technique that drills past surface symptoms by asking "Why?" repeatedly to uncover the true underlying problem.

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Duration30 minutes or more.
MaterialsFlipchart, markers.
InvolvementDirect User Involvement

The 5 Whys is a root cause analysis technique originally developed within the Toyota Production System. It works by repeatedly asking "Why?" in response to a problem statement, peeling back layers of symptoms until the fundamental cause is revealed. UX researchers, product managers, and design teams use it when a fix has already been attempted and failed, signaling that the real problem has not been correctly identified. The method requires no special tools or training, making it accessible to teams of any size or experience level. A facilitator presents the problem, and the group collaboratively answers each successive Why, grounding every response in evidence rather than assumption. The power of the 5 Whys lies in its simplicity: by enforcing structured questioning, it prevents teams from jumping to solutions prematurely. It is most effective when combined with data from analytics, user feedback, or observation, ensuring that each answer in the chain is factually supported rather than speculative.

WHEN TO USE
  • When a known fix has already been applied but the problem keeps recurring despite the intervention.
  • During post-mortem sessions after a product release reveals unexpected usability failures or user complaints.
  • When cross-functional teams need a quick, structured way to align on the true source of a problem.
  • In agile retrospectives to move beyond surface-level observations and identify systemic process issues.
  • When stakeholders disagree about the cause of a problem and need a facilitated path to consensus.
  • Early in discovery when user research data reveals symptoms but the underlying cause remains unclear.
WHEN NOT TO USE
  • ×When the problem has multiple interacting causes that cannot be traced through a single linear chain.
  • ×When quantitative data analysis or controlled experiments are needed to establish cause-and-effect relationships.
  • ×When the team lacks sufficient domain knowledge to provide factual answers at each level of questioning.
  • ×When political dynamics might cause participants to deflect blame rather than engage honestly with the process.
HOW TO RUN

Step-by-Step Process

01

Identify the Problem

The first step in the '5 Whys' method is to identify the problem or issue that needs to be solved. This involves discussing with your team or stakeholders the symptoms and impacts of the problem to ensure everyone is on the same page.

02

Ask the First Why

Once the problem has been identified, ask the first 'Why' question. This question should focus on understanding the root cause of the problem. For example, if the issue is that users are not finding a specific feature on your website, the first 'Why' could be: 'Why are users not finding the feature?'

03

Analyze the Answer

After asking the first 'Why,' analyze the answer provided by the team or stakeholders. This may involve gathering data, user feedback, or conducting further research to validate the given response.

04

Ask Subsequent Whys

Based on the analysis of the first answer, ask the next 'Why' question. This process is repeated until you have asked a total of five 'Why' questions. Each subsequent 'Why' should delve deeper into the root cause, helping you peel back the layers and identify the underlying issue.

05

Identify the Root Cause

After asking the fifth 'Why,' the final answer should reveal the root cause of the problem. At this point, you should have a clearer understanding of what is causing the issue and can begin brainstorming solutions to address it.

06

Implement Solutions

With the root cause identified, work with your team to develop and implement solutions that address the problem. Monitor the results of these changes to ensure they are effective in solving the issue and improving the user experience.

07

Review and Iterate

Lastly, review the entire process and the solutions implemented. Assess the effectiveness of the '5 Whys' method in identifying the root cause and solving the problem. If needed, iterate on the process and solutions, continually seeking to improve the user experience.

EXPECTED OUTCOME

What to Expect

After completing a 5 Whys session, the team will have a clearly documented causal chain linking an observable problem to its root cause. This chain provides a shared understanding of why the problem exists and creates alignment on what needs to change. The primary deliverable is an actionable root cause statement accompanied by one or more proposed countermeasures. Teams typically leave the session with a prioritized action plan that targets structural fixes rather than quick patches. Over time, repeated use of the 5 Whys builds a culture of deeper inquiry, reducing the likelihood that teams invest effort in solutions that only address symptoms.

PRO TIPS

Expert Advice

Be precise and specific when answering each Why, grounding responses in facts and observable evidence rather than opinions.

Write the entire chain on a physical board or flipchart so all participants can see the progression and spot logical gaps.

If the root cause remains unclear after five Whys, continue asking until the team reaches a structural or systemic cause.

Avoid assigning blame to individuals; focus on processes, systems, and design decisions that contributed to the problem.

Validate each answer before moving to the next Why by asking the team whether the stated cause actually explains the symptom.

Run parallel chains when a single Why has multiple valid answers to avoid oversimplifying complex problems.

Involve people closest to the problem, not just managers, to ensure answers reflect ground-level reality.

Document the final root cause and proposed countermeasures so the analysis leads to concrete action.

COMMON MISTAKES

Pitfalls to Avoid

Stopping at Symptoms

Teams often stop asking Why too early, settling on an intermediate cause rather than the true root. Keep asking until you reach a structural or systemic factor that can be addressed.

Accepting Vague Answers

Responses like "poor communication" or "lack of resources" are too broad to act on. Push for specific, evidence-based answers that point to concrete changes.

Blaming Individuals

The method should target processes and systems, not people. When answers point to a person, redirect by asking why the system allowed the error to occur.

Ignoring Branching Causes

Some Whys have multiple valid answers. Exploring only one branch can lead to an incomplete understanding. Run parallel chains when answers diverge.

Skipping Validation

Each answer should be verified with data or evidence before proceeding to the next Why. Unvalidated assumptions can send the entire analysis in the wrong direction.

DELIVERABLES

What You'll Produce

Problem Statement

A concise definition of the observed issue or user pain point to be investigated.

Root Cause Analysis

A documented chain of Why questions and answers tracing symptoms to causes.

Identified Root Cause(s)

The core systemic problem(s) uncovered through the iterative questioning process.

Proposed Solution(s)

Actionable countermeasures targeting the root cause to prevent recurrence.

Action Plan

A plan with owners, timelines, and resources for implementing solutions.

Results and Learnings

Post-implementation evaluation comparing before-and-after metrics and outcomes.

Process Improvement

Documented lessons learned to refine future problem-solving efforts.

FAQ

Frequently Asked Questions

METHOD DETAILS
Goal
Problem Discovery
Sub-category
Root cause analysis
Tags
5 whysroot cause analysisproblem-solvingToyota Production Systemtroubleshootingcontinuous improvementlean methodologywhy analysisdefect analysisprocess improvement
Related Topics
Root Cause AnalysisLean UXContinuous ImprovementDesign ThinkingAgile RetrospectivesSystems Thinking
HISTORY

The 5 Whys technique was developed by Sakichi Toyoda, the founder of Toyota Industries, in the 1930s as part of the Toyota Production System. It became a core tool in Toyota's approach to manufacturing quality and was later popularized by Taiichi Ohno in his 1988 book "Toyota Production System: Beyond Large-Scale Production." The method was designed to be simple enough for any factory worker to use without statistical training. As lean manufacturing principles spread beyond Japan in the 1990s, the 5 Whys migrated into software development, Six Sigma, and eventually UX research. Today it is used across industries from healthcare to technology, valued for its accessibility and its ability to cut through organizational complexity to reveal fundamental issues.

SUITABLE FOR
  • Identifying the original root cause when surface-level fixes keep failing
  • Troubleshooting recurring usability issues that resist simple solutions
  • Cross-functional teams investigating systemic product or process failures
  • Post-mortem analysis after a product launch reveals unexpected problems
  • Quick diagnosis sessions when time for extensive research is limited
  • Onboarding new team members into a problem space by walking through causal chains
  • Prioritizing design improvements by distinguishing symptoms from causes
  • Lean and agile retrospectives focused on continuous improvement
RESOURCES
  • What are 5 Whys?What are 5 Whys? The 5 Whys method is an iterative interrogative technique pioneered at Toyota Motor Corporation in the 1930s to explore the cause-and-effect relationships under...
  • The 5 Whys: How to make the most of this methodSometimes things go wrong, and your product is not performing as expected. 5 Whys is an easy-to-use technique that will help you find the root cause of the problem. You ask, "Why?" Question 5 times…
  • Five Whys in User ResearchThe 5 Whys technique was developed and fine-tuned within the Toyota Motor Corporation as a critical component of its problem-solving training. Today, the method is used far beyond Toyota. Know more about the method and its details.
  • 5 Whys Technique: An Essential Approach for Solving Design Problems in Digital ProductsThe five whys technique is a simple yet powerful tool used in product design to identify the root cause of a problem or issue. It involves asking "why" five times in succession, with each answer…
  • The 5 Whys in Design Thinking and How to Use Them – Make:Iterate
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