A3 problem solving is a structured method, developed at Toyota, that fits the whole story of a problem onto one sheet of A3 paper (297 × 420 mm): why it matters, what is happening now, the target, the root causes, the countermeasures, the plan and the results. The single page forces clear thinking and makes the reasoning easy to review. A3 thinking is the mindset behind the page: the disciplined, scientific way of understanding a problem before acting on it.
Updated in October 2026 by the TeamAssurance team.
What Is an A3?
An A3 is a one-page problem solving report, named after the international paper size it was first written on. Toyota used it to propose, solve and report on problems, and it spread with lean management to manufacturers and operations around the world. You will also see it called an A3 report, an A3 format or simply "an A3". For a one-minute definition, see What is an A3 report?
The A3 follows the PDCA cycle. The left side of the page is Plan: background, current condition, target and root causes. The right side covers Do, Check and Act: countermeasures, the implementation plan and follow-up. Read from top left to bottom right, it tells the story of a problem in the order the thinking happened.
If you want a blank layout to work from, download our free A3 problem solving template, which has prompts for each of the seven sections described below.
A3 Thinking vs the A3 Report
The A3 report is the document. A3 thinking is the discipline that produces it. The difference matters, because many organisations adopt the form and miss the point.
A3 thinking means:
- Going to the gemba. Facts about the current condition come from the place where the work happens, not from a meeting room.
- Understanding before solving. Most of the effort goes into the left side of the page. Countermeasures come only after causes are verified.
- Being concise. One page forces you to decide what matters. If it doesn't fit, you probably don't understand the problem well enough yet.
- Building agreement. The author shares drafts with the people affected, and the A3 improves with each conversation.
- Learning by doing. A mentor coaches the author with questions, so the A3 develops the person as well as solving the problem.
A filled-in template written alone at a desk, with solutions decided in advance, is an A3 report without A3 thinking. It rarely changes much.
The 7 Sections of an A3
Layouts vary between organisations, but most A3s contain these seven sections, plus a title, an owner and a date.
1. Background
What to write: why this problem matters now and how it connects to the organisation's goals, such as safety, quality, delivery or cost. Keep it to two or three lines a stranger could understand.
Common error: writing the history of the department, or stating the solution here ("we need a new machine").
2. Current Condition
What to write: what is actually happening, shown with facts, data and sketches. A trend chart, a Pareto chart or a simple process sketch is better than paragraphs of text. Quantify the gap in terms of the measure that matters.
Common error: describing the problem from memory or opinion rather than from observation at the gemba and real data.
3. Goal / Target Condition
What to write: what good looks like, as a measurable target with a date, for example "reduce X from 14 to 3 per week by the end of Q1".
Common error: a vague goal ("improve reliability") or a goal that is really an action ("install a sensor").
4. Root Cause Analysis
What to write: why the gap exists. Use root cause analysis tools such as a fishbone diagram to explore possible causes and the 5 whys to follow each one back to something you can act on. Then verify the likely causes at the gemba.
Common error: stopping at the first plausible answer, or blaming people ("operator error") instead of asking why the process allowed the error.
5. Countermeasures
What to write: what you will change to address each verified root cause. Lean practice says "countermeasure" rather than "solution" because each change is a hypothesis to be tested.
Common error: countermeasures that don't trace back to a root cause, or a list of generic actions such as "retrain staff" and "remind team".
6. Implementation Plan
What to write: who does what, by when. A simple table of actions, owners and due dates is enough, with any checkpoints for measuring progress.
Common error: actions owned by "the team" or with no dates, so nothing has a clear owner and nothing is late.
7. Follow-Up
What to write: whether it worked. Compare results against the target, record what you will standardise, and note what you will adjust or share with other areas.
Common error: closing the A3 as soon as the actions are done, without checking results over time or updating the standard so the problem doesn't return.
A Worked Example: Recurring Labeller Jams
Here is how the seven sections come together on a single page for a common packing line problem.
The example is illustrative: the line, the numbers and the causes are invented to show how an A3 reads.
Background. The labeller on packing Line 3 jams several times a shift. Each jam stops the line, and mislabelled packs have reached the end-of-line check, putting delivery and customer complaints at risk.
Current condition. The team logged every jam for four weeks. Line 3 averaged 14 jams per week, losing about 6 hours of packing time. Most jams happened in the first hour after a label reel change, and most were at the peel plate.
Goal. Reduce labeller jams on Line 3 from 14 to 3 or fewer per week within 12 weeks, with no mislabelled packs passing the end-of-line check.
Root cause analysis. A fishbone session with operators and maintenance listed possible causes, and the team checked each at the line. Two were confirmed. First, adhesive builds up on the peel plate because cleaning it is not part of any standard. Second, reel changes were done differently by each shift, and web tension was set by feel. A 5 whys on the tension issue showed there was no marked setting and no reel-change standard.
Countermeasures. Add a peel plate clean to the shift start-up checklist. Mark the correct tension setting on the unwind and write a one-page reel-change standard with photos. Train all three shifts on the new standard at the line.
Implementation plan. Each action has a named owner (team leader, maintenance technician or shift supervisors) and a due date over the first four weeks, with a jam count reviewed daily at the team's tier 1 meeting.
Follow-up. After six weeks the illustrative jam count averaged 3 per week. The reel-change standard was added to the line's standard work, the peel plate clean was kept in the start-up checklist, and the A3 was shared with the team leaders on Lines 1 and 2, which use the same labeller.
Notice what the A3 does not say: "buy a new labeller". The problem was solved by understanding the process, not by spending money first.
A3 vs 8D vs DMAIC
A3 is one of several structured problem solving methods. They share the same scientific logic but suit different situations.
| A3 | 8D | DMAIC | |
|---|---|---|---|
| Origin | Toyota and lean management | Automotive industry, widely used for customer complaints | Six Sigma |
| Structure | 7 sections on one page, following PDCA | 8 disciplines, from forming the team to recognising it | 5 phases: Define, Measure, Analyse, Improve, Control |
| Typical use | Everyday operational problems and improvement proposals | Customer or supplier quality issues needing formal containment and reporting | Complex, variation-driven problems needing statistical analysis |
| Typical duration | Days to a few weeks | Weeks, often with a customer deadline | Weeks to months |
| Who runs it | Frontline leaders and teams, coached by a mentor | Cross-functional team, often led by quality | Trained belts with project sponsors |
| Main strength | Clear thinking and shared understanding on one page | Containment and a formal record for customers | Statistical rigour |
Many organisations use all three. A3 is usually the default for day-to-day problems because it is light enough for team leaders to use regularly.
Using A3s in Project Reviews
A3s also work well for project reviews, where a team confirms its countermeasures worked, captures what it learned and standardises the change. Slide decks and verbal updates tend to bury the logic, so reviewers can't see how conclusions were reached and follow-up actions get lost. Because every A3 tells the same left-to-right story, reviewers know where to look.
A practical way to run an A3 review:
- Prepare the A3. The team updates it beforehand with current results and any changes made during implementation.
- Present the story. Walk through it from left to right: why the problem mattered, what the data showed, which root causes were found and how, what changed and what resulted.
- Ask questions, don't lecture. The reviewer's job is to develop the team's thinking, not to redo its work.
- Capture actions and lessons. Record follow-up actions and lessons on the A3 itself or in your daily management system, so they are tracked rather than forgotten.
As the number of A3s grows, a calendar view of A3 activities and review dates helps keep reviews from slipping.
Coaching an A3
In Toyota's approach, an A3 author typically has a mentor, usually their manager or an experienced problem solver. The mentor doesn't write the A3 or supply the answer. They ask questions that expose gaps in the thinking, and the author goes back to the gemba to find out.
Good coaching questions include:
- What is the problem, in one sentence?
- How do you know? What data or observation supports that?
- Have you seen this happen yourself?
- What is the gap between the current condition and the target?
- How did you confirm this is the root cause, and not just a symptom?
- How does this countermeasure address that cause?
- How will we know if it worked?
- What will you standardise, and who else should learn from this?
Keep coaching sessions short and frequent. Fifteen minutes at the A3 every few days does more than one long review at the end.
Keeping A3s Visible: Link Problem Solving to Tier Meetings
The most common reason A3s fail is not poor analysis. It is that they are written, filed and forgotten. Actions slip, nobody checks the results, and the same problem comes back months later.
The fix is to run A3 work through the routines that already run the operation:
- Tier 1. In daily tier meetings, the team reviews the measure the A3 is targeting, such as jams per shift, alongside safety and output. New problems are raised and the bigger ones become A3s.
- Tier 2 and Tier 3. Supervisors and managers check that A3 actions are on time and remove obstacles when they are not. Overdue actions and reviews are visible, not hidden in a folder.
- Monthly reviews. Leaders review the larger A3s that support strategic goals. Linking A3s to goals through hoshin kanri shows how problem solving on the shop floor contributes to the organisation's priorities.
This is how A3 problem solving becomes part of tiered daily management and wider continuous improvement, rather than a separate activity done when someone has time.
How TeamAssurance Supports A3 Problem Solving
TeamAssurance includes A3 problem solving as a structured method covering problem statement, current state, root cause analysis, target state, countermeasures and implementation plan. A3 projects can be linked to goals for larger improvement initiatives, and progress is tracked through tiered daily management, so A3s stay visible after they are written.
Frequently Asked Questions About A3 Problem Solving
What is an A3?
An A3 is a one-page report used to solve a problem or propose an improvement. It follows the PDCA cycle through seven sections: background, current condition, goal, root cause analysis, countermeasures, implementation plan and follow-up.
Why is it called an A3?
It is named after the A3 paper size (297 × 420 mm, about 11.7 × 16.5 inches) that Toyota used for these reports. The limit of one sheet is deliberate: it forces the author to be concise and focus on what matters.
What is A3 thinking?
A3 thinking is the mindset behind the A3 report. It means understanding a problem with facts from the gemba before acting, verifying root causes, testing countermeasures, building agreement and learning through coaching.
How long does an A3 take?
It depends on the problem. A focused operational problem might take a few days to a few weeks from first draft to verified results. Larger, cross-functional problems can run for several months. If an A3 has stalled for weeks with no progress, the scope is usually too broad.
What is the difference between an A3 and 8D?
Both are structured problem solving methods. An A3 fits on one page and is used for everyday problems and improvement proposals. 8D has eight disciplines, including formal containment, and is often required for customer or supplier quality complaints.
Is there an A3 template?
Yes. Our free A3 problem solving template is a printable A3 landscape page with prompts for all seven sections, plus a filled-in example.
Want to see how TeamAssurance keeps A3 problem solving visible through daily tier meetings? Book a demo.