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Meetings & Communicationnoun · /faɪv waɪz/

five whys

In simple English

The five whys technique is a systematic approach to root cause analysis popular in agile and lean development teams. When a problem occurs—such as a production outage, a critical bug, or a missed deadline—the team asks why it happened. Then they ask why to the answer they received, and repeat this process up to five times. Each iteration peels back another layer, moving from symptoms toward underlying causes. For example, a server might crash because memory ran out. Why? Because a process was leaking memory. Why? Because the developer did not close database connections properly. Why? Because there was no code review process. Why? Because the team was moving too fast to implement reviews. The final answer often points to a systemic or process issue, not just a technical one. Teams typically use five whys in retrospectives, incident postmortems, and when analyzing recurring problems.

What is the five whys technique and how do I use it to find the root cause of problems?

At a glanceCEFR B2
Commonness4/5
Versatility4/5
FormalityCasualFormalNeutral
Spoken ↔ WrittenSpokenWrittenBoth
Directness ↔ DiplomaticDirectDiplomaticNeutral
RegionUS and UK
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Say it like this

✓We should five whys this to get to the real problem.
✓Let us conduct a five whys analysis after the incident.
✓I want to understand the root cause, so let us run through the five whys.

Real examples

in a postmortem meeting

"The service went down last night. Let us do a five whys to understand what actually caused it."

in a retro

"We missed the deadline again. We should use five whys to figure out why our estimates are always wrong."

in a code review discussion

"Rather than just fixing the bug, let us step back and five whys it so we prevent similar bugs in the future."

Don't say this

Handle with care. Do not use five whys as a verb without 'do' or 'conduct.' It is a noun referring to a technique, not an action verb.

✕We five whys the problem yesterday.
✓We conducted a five whys analysis yesterday. OR We did a five whys on the problem yesterday.— Five whys is a noun (a technique or analysis), not a standalone verb. You conduct, do, or perform a five whys.
✕The five whys found that the database was the root cause.
✓The five whys analysis revealed that poor database connection handling was the root cause.— The technique itself does not find anything; the team doing the analysis finds the cause. Be clear about what the analysis revealed.
✕We asked five whys and got the answer immediately.
✓We asked five whys and discovered the root cause after exploring multiple layers.— Five whys is iterative and rarely reveals the root cause in just one or two questions. Emphasize the depth of investigation.

Other forms

noun

five whys

"The five whys technique helped us identify the real issue."

noun phrase

five whys analysis

"After the incident, we performed a five whys analysis."

noun phrase

conduct/do/perform a five whys

"Let us conduct a five whys to understand what went wrong."

Often used with

conduct a five whysStandard way to say you are performing the technique in formal or professional settings.
do a five whysMore casual version, commonly used in agile team conversations.
five whys analysisFormal noun phrase used in documentation and formal meetings.
root causeOften paired with five whys; the goal is to find the root cause, not just the symptom.
postmortemFive whys is frequently used during postmortem meetings after incidents or failures.

Similar words

root cause analysisBroader term; five whys is one specific technique for doing root cause analysis.
causal analysisGeneral term for any analysis that seeks causes rather than symptoms.
problem investigationMore general; five whys is a structured method of investigation.

Opposites

surface fixquick patchsymptom treatment

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Practice

Try it

4 quick exercises

Pick the most natural phrasing

1. Your team experienced a data loss incident. How do you naturally phrase what you want to do next?

Complete the sentence

2. After the server outage, the team will _______ to identify the underlying problem.

Spot the mistake

3. Which sentence uses five whys incorrectly?

Rewrite naturally

4. Rewrite this using five whys naturally: 'We need to understand why the API kept timing out, and we should ask questions repeatedly until we find the real problem, not just the obvious one.'

Questions

Quick poll

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