Problem Solving & Quality · Act
A3 Report
Tell the whole problem-solving story on one A3 sheet — background, current state, goal, causes, countermeasures, plan, follow-up — and use it to coach and align.
- Time2 h
- FormatSolo
- StageAct
A3 Report: what it is and why it works
An A3 report tells the entire story of a problem and its solution on a single sheet of paper of A3 size, roughly 11 by 17 inches, which is the usual substitute in North America. The left side covers the problem: background and why it matters, the current condition shown with data and a sketch, the target, and the root-cause analysis. The right side covers the response: countermeasures linked to causes, the implementation plan with owners and dates, and the follow-up that confirms the result. The title names the problem, not the solution.
The one-page constraint is the point. It forces the author to decide what matters, to show data visually and to make the logic from problem to cause to countermeasure visible at a glance. In the Toyota tradition, the A3 is also a coaching and alignment tool: the author drafts it, often in pencil, and reviews it with a coach and with the people affected, who ask questions rather than impose answers. This makes gaps in reasoning obvious early. The A3 follows PDCA logic, can start from a deviation statement and, once complete, becomes a compact record for the lessons learned register.
What you need
- A problem that matters, with an owner willing to work through it
- Current data on the problem and a way to show it visually
- Access to the workplace and the people involved
- A coach or manager available for regular reviews
What you get
- A single sheet showing problem, analysis, countermeasures and follow-up
- Alignment among the people involved on the causes and the plan
- A coached improvement in the author's problem-solving skill
- A compact record for lessons learned and future reference
When to use it
When a problem file runs to forty pages and no manager reads past the first one.
How to do it, step by step
- Take one A3 sheet in landscape; title it with the problem, not the solution, and add owner and date.
- Left side: background and why it matters, current condition with data and a sketch, target, root-cause analysis.
- Right side: countermeasures linked to causes, implementation plan with owners and dates, follow-up and results.
- Write it in pencil and review it with the people involved and with a coach who asks questions rather than giving answers.
- Update it as the work progresses and use the final version as the record and the lesson learned.
Worked example: Hydraulic hose failures on underground loaders
Illustrative scenario — figures are realistic but not from a real company.
An underground gold mine runs a fleet of nine load-haul-dump loaders. Hydraulic hose failures caused about 60 hours of unplanned downtime per month, and each failure also meant an oil spill to clean up underground. A 30-page maintenance report existed, but site management had not acted on it.
- The maintenance planner started an A3 titled "Hydraulic hose failures on LHD fleet cause 60 h/month downtime". Background showed the cost of downtime and cleanup, and the target was 20 hours per month within six months.
- Current condition: a Pareto chart of failures by location on the machine showed that 70 % occurred on the boom and bucket hoses, and a sketch showed where hoses rubbed on the articulation joint.
- Root-cause analysis, reviewed with the fitters, found two causes: abrasion from incorrect routing after replacement, and hoses made up in the workshop without a length standard.
- Right side: countermeasures included routing templates with photos for each hose, a hose length table, protective sleeves at contact points and a check at each 250-hour service. The plan had owners and dates for each.
Result. The mine manager approved the plan in a 20-minute review, which the thick report had never achieved. Five months later, hose-related downtime averaged 22 hours per month, and the follow-up section showed which countermeasure had most effect. The planner noted that squeezing the story onto one page forced him to drop half his analysis, which turned out to be irrelevant.
Common pitfalls and how to avoid them
- Titling the A3 with the solution, such as "install new hose sleeves".Title it with the problem and its impact; the solution comes on the right side, after the analysis.
- Filling the sheet with text in small fonts to make everything fit.Use charts, sketches and short statements; cut content that does not support the logic.
- Writing the A3 alone and presenting it as finished.Draft it early, review it with the coach and the people involved, and revise it as understanding improves.
- Listing countermeasures that are not linked to the causes on the left.Check that each countermeasure addresses a stated cause; remove or justify any that do not.
Frequently asked questions
What is an A3 report in lean?
An A3 report is a one-page document, named after the paper size, that summarizes a problem-solving effort from background through root cause to countermeasures and follow-up. It originated at Toyota as both a communication format and a way to develop problem-solving thinking. Its value comes from the discipline of the single page and the coaching conversations around it.
What are the sections of an A3 report?
A common layout has the title, owner and date at the top. The left side holds background, current condition, target and root-cause analysis; the right side holds countermeasures, the implementation plan and follow-up with results. Different organizations adjust the headings, but the flow follows PDCA, from understanding the problem to confirming the result.
Can I use 11x17 paper for an A3 report?
Yes. A3 paper measures about 11.7 by 16.5 inches, and 11 by 17 inch ledger or tabloid paper is the usual equivalent in the United States. What matters is the single-sheet constraint, not the exact size. Many teams also keep an electronic A3 template with the same layout, but printing it for review conversations remains common.
Origin
A3 report — Toyota practice; described by Durward Sobek & Art Smalley, Understanding A3 Thinking, 2008, and John Shook, Managing to Learn, 2008.
Used in these playbooks
One-page improvement cycle 3 weeks
Three weeks for a local problem owned by a team leader: see it on site, tell it on one A3, choose the countermeasure openly, pilot it and make it the new standard.
Related methods
- PDCA CyclePlan a change on a hypothesis, do it small, check the result against the prediction, then act: standardize it…
- Deviation StatementWrite one sentence: object, defect, expected value, observed value, since when. No cause, no culprit, no…
- Lessons Learned RegisterTurn each closed problem into a short, searchable record — symptom, cause, fix, where it applies — and feed…
More in “Act”
Plan, pilot and run the fix — with owners, dates and a structured roadmap.