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Root cause analysis example: 6 worked samples and a template

A root cause analysis example for six settings, from a machine stoppage to warehouse picking errors, plus root cause statement wording and a free one-page RCA template.

Updated October 26, 2026 · 8 min read · Root Cause Analysis Software

By the lean-stack editorial team
  1. ProblemOrders shipped with the wrong label
  2. Why?The packer took the label from the wrong pile
  3. Why?Two label types sit in the same tray
  4. Why?A new product was added without a new tray
  5. Why?Product launches have no packing-area check

Root causeNo packing-area step in the product launch process

CountermeasureAdd a packing check to the launch checklist, with one tray per label

An illustrative chain. The root cause is a missing process step, not the packer.

A good root cause analysis example shows a clear problem and a chain of causes backed by evidence. It ends with a root cause statement and a countermeasure that prevents recurrence. This guide gives six root cause analysis samples, each using a different technique.

All six are illustrative examples written to show the method. They are not real company cases, and the numbers are invented for teaching.

Each example is drawn as the diagram its technique produces. The one-page template, worksheets for 5 Whys, fishbone and is/is-not, and an Excel version with a Pareto sheet are free to download at the end.

Key takeaways

A root cause is a process condition you can change that, if fixed, stops the problem coming back.

Different problems suit different root cause analysis techniques: 5 Whys, fishbone, is/is-not, fault tree, Pareto and 8D.

Each example here follows the same order: problem, method, chain of causes, root cause statement, countermeasure.

A strong root cause statement describes a cause in the system, never a person's failing.

Verify each cause with evidence before acting on it.

What does a good root cause analysis look like?

A good root cause analysis defines the problem precisely and tests each cause against evidence. It stops at a cause the team can control and ends with a countermeasure and a check. The write-up is short enough to read in a few minutes.

Fixing symptoms instead of causes has a measurable cost. In a NIST survey of US manufacturers, plants that relied most on reactive maintenance, fixing equipment after it fails, had 3.3 times more downtime and 16 times more defects than plants that relied on it least.

The types of root cause analysis differ in how they find causes. Sequential methods such as 5 Whys follow one chain. Diagram methods such as fishbone and fault trees map many possible causes. Data methods such as Pareto charts show which problem to attack first.

Many teams record the result on an A3 report. See the guide to A3 problem solving, and the root cause analysis page for the full overview.

Which technique fits which problem

  • 5 Whys

    A single, repeatable failure you can see, like a machine fault.

    Example 1 below

  • Fishbone

    There are many possible causes to sort before testing.

    Example 2 below

  • Is/is-not

    A fault appears in some places, batches or times and not in others.

    Example 3 below

  • Fault tree

    A failure needs several things to go wrong together, as in safety or IT systems.

    Example 4 below

  • Pareto chart

    There are many problem types and you need to pick the biggest first.

    Example 5 below

  • 8D

    A customer complaint needs formal containment, a team and a written report.

    Example 6 below

Techniques also combine. A Pareto chart picks the problem, a fishbone lists candidate causes, and 5 Whys follows the strongest one down.

Example 1: machine stoppage with 5 Whys

Problem

A packing machine stops about three times a shift because the sealing jaw jams.

Method

5 Whys, asked at the machine.

  1. Why 1

    The jaw jams because film is out of position.

  2. Why 2

    The film shifts because the feed roller slips.

  3. Why 3

    The roller slips because its surface is worn and glazed.

  4. Why 4

    The surface is worn because replacement is not on any schedule.

  5. Why 5

    There is no schedule because the roller was never listed as a wear part.

Each answer becomes the next question. The last rung is a condition the team can change.

Root cause statement

The roller has no planned replacement because it is missing from the preventive maintenance list.

Countermeasure

Add the roller to the list with a replacement interval, then check stoppages weekly for a month.

A blank 5 Whys worksheet with room for the evidence behind each answer.

Worksheet (PDF)Workbook (.xlsx)

Example 2: late deliveries in an office with a fishbone

Problem

A back-office team sends about one in five customer quotes after the promised date.

Method

A fishbone diagram, with the team listing causes under people, method, tools, information and environment.

The group tests each branch against ten late quotes. Seven of them waited for pricing approval, and the approval request had no owner or due date. Approvers received it by general email and checked it only once a day.

Only the causes the team confirmed against the ten late quotes are drawn. On a phone, scroll sideways.

Root cause statement

Quotes are late because pricing approval requests have no named approver or time limit.

Countermeasure

Route requests to a named person with a four-hour response standard and a visible queue.

A blank fishbone with the five categories from this example, ready to print large.

Worksheet (PDF)Workbook (.xlsx)

Example 3: software outage with a fault tree

Problem

An online booking service went down for 45 minutes.

Method

A fault tree, which starts at the failure and branches downward into the combinations of events that could cause it.

The service failed because both database connections were unavailable. The first failed on a certificate expiry. The second failed because the backup used the same certificate, so one expiry removed both paths.

Booking service down for 45 minutes
Main database connection fails: its certificate expired
Backup connection fails: it used the same certificate
Basic event: one shared certificate, and no alert before it expired
Read top down: the service fails only if both paths fail together, and one expiry removed both.

Root cause statement

The backup connection shared the certificate of the main one, and no alert warned of its expiry.

Countermeasure

Use separate certificates and add an expiry alert 30 days ahead. Bell Labs developed fault tree analysis in the early 1960s for missile safety work.

Process gaps are a common root cause in outages. In the Uptime Institute's 2025 outage analysis, 85% of major data center outages caused by human error stemmed from staff not following procedures, or from flaws in the procedures themselves.

Example 4: clinic waiting times with a Pareto chart

Problem

Patients at a small clinic wait too long before seeing a nurse.

Method

A Pareto chart, which counts causes and ranks them so the biggest few are tackled first.

Staff log the reason for each of 100 long waits. Missing registration details account for 46, nurse room not ready for 25, late arrival of patients for 15, and other reasons for 14. The registration problem comes from paper forms left incomplete at the front desk.

00%2525%5050%7575%100100%46251514
Missing registration detailsNurse room not readyLate arrival of patientsOther reasons
The tallest bar comes first. The line shows the running share: the first two reasons cover 71 of 100 waits.

Root cause statement

Registrations are incomplete because the form allows submission with required fields blank.

Countermeasure

Make required fields mandatory at check-in, then re-run the count after two weeks.

Healthcare organizations run root cause analyses on serious events too. The Joint Commission reviewed 1,411 sentinel events in 2023, and falls made up 48% of them.

The workbook's Pareto sheet sorts your counts and draws this chart for you.

Workbook (.xlsx)

Example 5: label complaint with is/is-not analysis

Problem

A customer reports that product labels peel off.

Method

Is/is-not analysis, popularized by Kepner and Tregoe. It compares where and when the fault occurs with where and when it could occur but does not.

The peeling is found on one batch, one filling line and cartons stored near the loading door. It is not found on other lines or other batches. The difference is a new adhesive roll loaded on that line, and cold, damp storage.

QuestionIsIs not
Which batch?One batchOther batches
Which line?One filling lineOther lines
Where stored?Cartons stored near the loading doorNot compared in this example
What differs: a new adhesive roll loaded on that line, and cold, damp storage.
The distinction column points at what is different about the cases where the fault appears.

Root cause statement

Labels peel because the adhesive roll used on line 2 was not rated for cold, damp storage.

Countermeasure

Specify the adhesive grade on the material standard and add a storage check at goods-in.

A blank is/is-not worksheet for what, where, when and how much.

Worksheet (PDF)Workbook (.xlsx)

Example 6: warehouse picking errors with 8D

Problem

A warehouse ships the wrong item on about two orders in a hundred.

Method

8D, an eight-discipline team method that Ford documented in the late 1980s, covering containment, root cause, corrective action and prevention.

As containment, the team adds a scan check at packing. Analysis shows most errors involve two products stored in adjacent bins with similar packaging. Pickers rely on a visual match, because the bin label shows only a short code.

  1. D1Form the team

    Not part of this short example

  2. D2Describe the problem

    Wrong item on about 2 orders in 100

  3. D3Contain

    Scan check at packing

  4. D4Find the root cause

    Look-alike items in adjacent bins, no scan at pick

  5. D5Choose corrective actions

    Separate the items, require a scan at the bin

  6. D6Implement and validate

    Not part of this short example

  7. D7Prevent recurrence

    Review error counts weekly

  8. D8Recognize the team

    Not part of this short example

The steps this short example covers are filled in; a full 8D report fills in all eight.

Root cause statement

Picking errors occur because look-alike items sit in adjacent bins with no scan confirmation at pick.

Countermeasure

Separate the items, require a scan at the bin and review error counts weekly. See also poka-yoke.

How to write a root cause statement

Write a root cause analysis statement as a cause-and-effect sentence about a process condition: this problem occurs because this condition exists. Use a simple template and keep it to one sentence.

ProblemLate quoteshappen becauseProcess conditionapproval requests have no named ownerwhich allowsMechanismthem to sit unseen
The template with the guide's late quotes example in each slot.

Test the statement three ways

  • Can you verify it with evidence?
  • Would fixing it stop the problem?
  • Is it a condition, not a person?

The root cause analysis software and CAPA software categories include tools that store such statements and actions.

A one-page root cause template

Copy these ten fields onto one sheet, or onto an A3. Keep each to a few lines.

Root cause analysis, one page

Filled with Example 1: the packing machine

  1. 1

    Problem statement

    What, where, when and how much, against the standard.

    The line 2 packing machine has stopped about 3 times a shift since 1 September, against a target of under 1.
  2. 2

    Scope

    What is in and out.

    One machine on all shifts.
  3. 3

    Containment

    What protects the customer now, and who started it.

    A full check at packing.
  4. 4

    Technique

    The method chosen and why.

    5 Whys because the failure is mechanical and repeats.
  5. 5

    Cause chain

    Each cause in order, one line each.

    1. 1. The jaw jams because film is out of position.
    2. 2. The film shifts because the feed roller slips.
    3. 3. The roller slips because its surface is worn and glazed.
    4. 4. The surface is worn because replacement is not on any schedule.
    5. 5. There is no schedule because the roller was never listed as a wear part.
  6. 6

    Evidence

    How each cause was confirmed.

    A photo of the worn roller.
  7. 7

    Root cause statement

    One sentence: [Problem] happens because [process condition], which allows [mechanism] to occur.

    The roller has no planned replacement because it is missing from the preventive maintenance list.
  8. 8

    Countermeasure

    The change to the process, with an owner and a due date.

    Add the roller to the list with a replacement interval.Owner and due date: added by the team.
  9. 9

    Check

    The measure, the target and the review date.

    Stoppages under 1 a shift for 4 weeks in a row.
  10. 10

    Standardize

    Which document, checklist or training changed, so the fix outlasts the team that made it.

    The preventive maintenance list now includes the roller and its replacement interval.
Each field's example comes from this guide. Illustrative: the plant and numbers are made up.

Free downloads

Root cause analysis template and worksheets

The one-page template prints with each field's prompt. The worksheets cover 5 Whys, fishbone and is/is-not. The workbook adds a Pareto sheet that sorts your counts and draws the chart, and an action list.

Root cause analysis template in Excel (.xlsx)

Common root cause analysis mistakes

The most common mistake is blaming a person, such as operator error, which ends the analysis before the system is examined. Ask why the process let the error happen or go unnoticed.

Another mistake is stopping at a symptom. A jammed machine, a late quote and a wrong pick are effects, so ask why again until you reach a cause you can change.

Teams also act on guesses without evidence, pick a single cause when several combine and skip the check that confirms the fix worked. Going to the real place helps, as the gemba walk checklist shows.

Frequently asked questions

What is a root cause analysis example?
A root cause analysis example walks from a defined problem through a chain of verified causes to a root cause statement and a countermeasure. The six samples on this page are illustrative, not real company cases.
How do you write a root cause analysis?
Define the problem with facts, choose a technique and test each cause against evidence. Then write a root cause statement and set a countermeasure with a follow-up check. The A3 problem solving guide gives a step-by-step format.
What are the types of root cause analysis?
Common techniques include 5 Whys, fishbone diagrams, is/is-not analysis, fault trees, Pareto charts and 8D. Some follow one chain of causes, while others map many causes or rank them by frequency. See 5 Whys and the fishbone diagram.
What is a root cause analysis statement?
A root cause analysis statement is one sentence that says the problem occurs because of a specific, changeable process condition. It should be verifiable and should not blame a person.
How many whys should a root cause analysis use?
Five is a guideline, not a rule. Stop when you reach a cause you can verify and fix, which might take three whys or seven.
Is there a root cause analysis template?
Yes. The one-page template on this page has ten fields, from problem statement and containment to the check and the standard that changed. It fits on an A3 sheet.

Choosing Root Cause Analysis Software?

Read the buying guide: what to look for, mistakes to avoid and questions to ask vendors.

Open the guide

Related guides

Sources

Books and papers show their publication year. Web pages show the month we last checked them.

  1. 1.Taiichi Ohno, Toyota Production System: Beyond Large-Scale Production (Productivity Press, 1988)
  2. 2.Kaoru Ishikawa, Introduction to Quality Control (3A Corporation, 1990)
  3. 3.Durward K. Sobek II and Art Smalley, Understanding A3 Thinking: A Critical Component of Toyota's PDCA Management System (Productivity Press, 2008)
  4. 4.Charles H. Kepner and Benjamin B. Tregoe, The Rational Manager (McGraw-Hill, 1965)
  5. 5.Clifton A. Ericson II, Fault Tree Analysis: A History (Proceedings of the 17th International System Safety Conference, 1999)
  6. 6.Douglas S. Thomas and Brian A. Weiss, NIST, Economics of Manufacturing Machinery Maintenance: A Survey and Analysis of U.S. Costs and Benefits (NIST AMS 100-34) (nist.gov, checked October 2026)
  7. 7.Uptime Institute, Uptime Announces Annual Outage Analysis Report 2025 (uptimeinstitute.com, May 2025)
  8. 8.The Joint Commission, Now available: 2023 Sentinel Event Data Annual Report (jointcommission.org, May 2024)

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