Topic guide · 24 articles
Root cause analysis and problem solving
Root cause analysis is the structured investigation that finds the underlying condition behind a manufacturing problem, so the fix removes the cause instead of the symptom and the problem stops coming back. It starts with a precise, factual problem statement and then uses the tool that fits the problem: the 5 Whys for a single chain of cause and effect, a fishbone diagram when causes sit in several areas at once, and A3 or 8D for larger, cross-functional problems. These guides explain each method, when it works and when it does not, and how to move a plant from daily firefighting to real problem solving.
Quick guides: The 6 Ms of production, Root cause analysis, Problem solving methods, Fishbone diagram, Pareto chart, A3 problem solving, Practical problem solving, 5W1H, 5 Whys, 8D problem solving, 5W1H questions
Also: Model area 90-day plans, A3 examples: three worked A3 reports, with a coach's notes, 5 whys examples: worked chains with the evidence for each why, Lean in 7 days, day 6: problem solving, PDCA examples: six worked cycles from the shop floor
Picking the root cause tool for the problem
- 1
Write a precise problem statement
What, where, when and how much, from facts, not opinions. - 2Decision
Large or cross-functional problem?
- Yes:
- A3 or 8D
- No:
- next question
- 3Decision
Causes in several areas at once?
- Yes:
- a fishbone diagram
- No:
- the 5 Whys, for one chain of cause and effect
- 4
Fix the cause, then check it holds
The problem stops coming back, not just today's symptom.
Start here
- 1
The 6Ms of Production: A Complete Manufacturing Guide
The 6 Ms are Man, Machine, Method, Material, Measurement and Mother Nature. What each covers and how to use them to find a root cause.
Read the guide - 2
5G Methodology: Toyota's Problem Investigation Framework
The 5G method checks five things before naming a cause: Gemba (place), Gembutsu (object), Genjitsu (facts), Genri (principles), Gensoku (standards).
Read the guide - 3
5W1H Method: Defining Problems for Root Cause Analysis
The 5W1H method asks Who, What, Where, When, Why and How. See each question answered, a worked factory example, 5W1H vs 5 Whys, and a template.
Read the guide
All 24 articles on root cause analysis and problem solving
What the 24 articles on root cause analysis and problem solving cover
- From firefighting to daily problem solving7 articles
- 5 Whys and fishbone diagrams6 articles
- A3, 8D and fault tree analysis5 articles
- Defining the problem4 articles
- Root cause analysis basics2 articles
Root cause analysis basics (2)
Defining the problem (4)
5 Whys and fishbone diagrams (6)
- What is the 5 Whys Root Cause Analysis Method?
- 5 Whys: When It Works and When It Doesn't
- Fishbone Diagram: A Root Cause Analysis Visual Tool
- Fishbone Diagrams: Effective Facilitation Techniques for Manufacturing Teams
- The 6Ms of Production: A Complete Manufacturing Guide
- The 5Ms of Lean Manufacturing: How Fishbone Diagram Categorizes Causes
A3, 8D and fault tree analysis (5)
From firefighting to daily problem solving (7)
- The 3-Step Framework to End Daily Issue Firefighting
- Why Firefighting Kills Manufacturing Productivity in 2026
- From Reactive Firefighting to Proactive Operations: 90-Day Plan
- Daily Issue Chaos Costs Manufacturers $1.7M Annually
- Breaking the Cycle of Shop Floor Chaos Forever
- Real-Time Problem Dashboards End Shift Reports Forever
- Why Digitize Abnormality Reporting (F-tags)
Where LeanSuite helps
AI Root Cause Analysis
Describe a problem, answer the AI's questions, and get the likely root causes and an action plan.
See AI Root Cause AnalysisDaily Issue Management
Gives frontline teams one place to flag, track and resolve issues in real time, so the same fires stop coming back every week.
See Daily Issue ManagementNon-Conformance (NCR)
Moves non-conformance reports into an automated workflow and links each defect report to root-cause problem solving.
See Non-Conformance (NCR)
Free tools
- Lean method navigatorSix questions about one problem, then the lean method to start with, the two that follow, why each fits, five steps for Monday and what it will not solve.
- Fishbone diagram makerName the problem, list causes under the 6M bones, and download the Ishikawa diagram as a PNG or SVG.
- 5 Whys canvasWrite the problem, answer up to five whys, state the root cause and countermeasure, then print the one-page canvas.
- Pareto chart makerPaste categories and counts: sorted bars, cumulative percentage line and the vital few at the 80% line, as a PNG or SVG.
Free templates
- 5W1H templateWho, what, when, where, why and how: a problem statement built from checked facts, and an action plan with nothing left open.
- 5 Whys templateA problem statement, a why chain that can branch, evidence for every answer, root causes and countermeasures that are checked.
- 8D report templateD0 to D8 with targets, containment counts, occurrence, escape and systemic causes, verified actions and a worked example.
- A3 problem solving templateThe standard seven-box A3 from background to follow-up, with a filled-in worked example. PDF and Excel.
- Pareto chart templateA tally sheet, the Pareto by count and by cost with the cumulative line and the 80 percent threshold, and a before and after comparison. Excel sorts and draws it.
- Corrective action request (CAPA) formOne problem from containment to proof the fix worked, with occurrence and escape causes and a closure check that tells you when it can close.
- Incident investigation report templateFacts and a sourced timeline, causes at three levels, actions by the hierarchy of controls, a US recordkeeping screen and a closure check.
- Root cause analysis templateOne report from problem statement to proof: containment, evidence, analysis, verified causes, actions and the effectiveness check.
- 5G investigation sheetConfirm the facts before naming a cause: 5W1H, the five G's with 20 prompts, the gap against the principle and the standard, and the countermeasures.
- Is / is not analysis templateWhat, where, when and extent with is, is not, distinctions and changes, then each possible cause tested against every pair and ranked.
- Fault tree analysis templateA drawing area with the FTA symbols, an event table with probabilities and minimal cut sets, and the gates worked out bottom-up in Excel.
- Breakdown analysis reportOne equipment breakdown from the stop to the 90-day check, plus a breakdown log with repeat flags, MTBF and MTTR by asset and a Pareto of causes.
- Scatter diagram templateUp to 50 pairs with a group code, r and R², the least squares line, the quadrant count and r for each group.
- Process improvement method selectorEight questions about one problem, an example rule that suggests a method and a matrix of nine methods: when each fits, the usual team and time, and the template to start with.
- Focused improvement 90-day model area planThirteen weeks from the loss Pareto to standardized fixes on one model line, a KPI board, the day-90 gate and expansion waves.
Free training decks
- Root cause analysis training presentation: 5 whys and fishboneDefine, contain, the 5 whys, the fishbone diagram and verifying the cause, in 18 slides with a team activity.
- DMAIC training presentationDefine, measure, analyze, improve and control, with the main tools of each phase, in 16 slides.
- 5 Whys training presentationOhno's machine example, how to ask good whys, when to stop and where the method falls short, in 20 slides with a team exercise.
- A3 problem solving training presentationThe seven boxes, the three kinds of A3, how to write and coach one, with two worked example slides and a 30-minute exercise, in 20 slides.
- 8D problem solving training presentationD0 to D8, containment, the root cause and the escape point, proving a fix and preventing repeats, in 20 slides with a team exercise.
Free printable posters
- PDCA cycle posterPlan, do, check, act as a cycle, with what to do in each step.
- 5 whys posterOhno's classic machine example, from a blown fuse to a missing strainer, with the rules for asking why.
- 8D problem solving posterThe eight disciplines plus D0, from forming the team to recognizing it, in one view.
- 7 basic quality tools posterIshikawa's seven tools, each drawn and explained in one line.
- PDCA, DMAIC and A3 side by side posterThe three methods lined up step by step, with when each fits: PDCA for every day, DMAIC for data and variation, A3 for agreement and coaching.
- Which problem-solving tool posterFive questions down the page lead to the tool that fits: Is/Is Not, just do it, fishbone, 5 Whys, DMAIC or an A3.
- Incident investigation steps posterEight steps from making the scene safe to checking that the fix worked and spreading it.
- 5W1H problem description posterWhat, where, when, who, which and how, with a vague complaint rewritten as a clear problem statement.
- Is / Is Not analysis posterWhat, where, when and how big the problem is and is not, and the question each difference raises.
- Fishbone 6M questions posterThe questions to ask under each of the six Ms, and four rules that turn a fishbone into evidence.
- Human error root causes posterSix reasons a person makes a mistake, and the fix that fits each one. Retraining fits only one of them.
- Why made, why missed posterA defect that reached a customer has three root causes to find: why it was made, why it was missed, why the system allowed it.
- Strong and weak countermeasures posterStronger, middle and weaker countermeasures: pick one that does not depend on someone remembering.
- How to read a Pareto chart posterThe bars, the cumulative line, what to count, splitting the top bar and showing the fix worked.
- Breakdown analysis posterSeven steps after a breakdown, from the facts to the root cause, the fix, and the standards that stop it coming back.
- A3 report layout posterThe seven boxes of an A3 report, left to understand and right to fix, and what goes in each.
FAQ
Questions about root cause analysis and problem solving
Root cause analysis (RCA) is the structured investigation that identifies the underlying condition behind a manufacturing failure rather than the visible symptom. A corrective action on a symptom removes the evidence for a while, but the same condition produces the same failure again; RCA takes the investigation past the symptom to the process condition, equipment failure mode, human factor or material condition that has to change.
Use the 5 Whys when the problem has a single, linear chain of cause and effect. When several causes interact, a 5 Whys follows one thread and misses the others, so a fishbone diagram, which maps every area of cause before the team narrows down, is the better starting point.
Man, Machine, Method, Material, Measurement and Mother Nature (the environment). They are the six categories of a fishbone diagram, and they make an investigation team look at every major area of cause, including environment and measurement, the two that are most often missed.
8D is a team-based corrective action method with eight disciplines that puts containment before the root cause investigation, which makes it the usual response when a failure has already reached the customer; automotive customers often require it from suppliers. A3 problem solving, from the Toyota Production System, takes a problem from definition to root cause and countermeasures on a single A3 sheet, so the findings and the plan are easy to share.
More topics
- Lean manufacturing fundamentals
- Kaizen and continuous improvement
- Quality management
- TPM and maintenance
- 5S and visual management
- Value stream mapping and flow
- Standard work, SOPs and training
- Safety management
- Lean leadership and employee engagement
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