For the full guide, with a worked example and how to run A3 project reviews, read A3 format explained.
Where the A3 comes from
The format grew out of Toyota's practice of summarising problems and proposals on a single sheet of A3 paper. The constraint is deliberate. Fitting everything on one page forces the author to understand the problem deeply and to communicate only what matters. It is as much a coaching tool as a report: a manager reviews it with the author and asks questions until the logic holds.
The standard sections
An A3 reads left to right: the problem story first, then the plan.
Formats vary, but most problem-solving A3s follow the PDCA cycle from left to right:
| Section | What it answers |
|---|---|
| Background | Why does this problem matter now? |
| Current state | What is actually happening, with facts and data? |
| Goal or target state | What does good look like, and by when? |
| Root cause analysis | Why is there a gap between current and target? |
| Countermeasures | What will we change to address the root cause? |
| Implementation plan | Who does what, by when? |
| Follow-up | How will we check it worked, and what did we learn? |
The left side covers Plan. The right side covers Do, Check and Act.
How to write an A3 report
- Identify the problem. Write a problem statement free of solutions, and say why it matters now.
- Grasp the current state at gemba, with charts and sketches rather than paragraphs.
- Find the root cause with the team members who do the work, using tools such as the 5 whys.
- Propose solutions. List proposed solutions as countermeasures tied to verified causes, and agree them with stakeholders before acting.
- Implement, check and follow up, then record what was learned.
Expect several revisions, and review it with a coach or the owner's manager at each stage. Our A3 report template sets out these sections on one page, and the A3 problem solving template adds a filled-in example.
Common mistakes
- Treating the A3 as a form to complete after the decision has already been made.
- Skipping straight from current state to countermeasures without verified causes.
- Crowding the page with text instead of visuals.
- Never filling in the follow-up section, so nobody checks whether the countermeasures held.
Example
A warehouse team sees pick errors rising. Their A3 shows the trend, maps where errors occur, and uses a fishbone and 5 whys to trace most errors to similar-looking products stored side by side. Countermeasures re-slot those items and add location labels. The follow-up section tracks errors weekly and records the new slotting rule as standard work.