What an A3 is
An A3 is a one-page problem-solving report, named for the A3 paper size (roughly 11 × 17 inches) it was traditionally drawn on. It comes from the Toyota Production System, where the single page forces the team to boil the problem down to what actually matters. The left side tells the story of the problem; the right side tells the story of the fix.
The structure follows the PDCA cycle — Plan, Do, Check, Act — which W. Edwards Deming popularized from Walter Shewhart's earlier work on quality control. The point of the cycle is that a countermeasure is a hypothesis: you test it, measure it, and only standardize it once the data shows it worked.
Kaizen event vs. everyday kaizen
Kaizen means "change for the better" and refers to continuous, incremental improvement by the people doing the work. A kaizen event (sometimes called a kaizen blitz) is a focused effort — often three to five days — where a team attacks one process. Either way, an A3 is a good way to document it: it keeps the team honest about the root cause and gives management a single page to review.
Writing a good A3
- One problem per A3. If the background lists three problems, you need three A3s.
- Lead with data. The current condition should have a number in it. "Downtime is bad" is an opinion; "line 2 lost 14 hours a week in September" is a starting point.
- Every countermeasure traces to a root cause. If you can't point to the cause it addresses, it's a guess.
- Don't skip Act. Most improvements fade because nobody updated the procedure, PM, or training. Standardizing is what makes a fix permanent.
FAQ
How does the 5 Whys import work?
If you've used our 5 Whys tool in this same browser, the import button copies your chain of whys and root cause into the root-cause box, and fills in the title and background if they're empty. Nothing leaves your browser.
Will it print on letter-size paper?
Yes. The print layout is landscape and scales to fit letter or A4. Choose "Save as PDF" in the print dialog to keep a digital copy.
Where is my report saved?
Only in this browser on this device. Print or copy it to keep a permanent record.
Sources & standards
- Imai, Masaaki. Kaizen: The Key to Japan’s Competitive Success. McGraw-Hill, 1986.
- Deming, W. Edwards. Out of the Crisis. MIT Press, 1986. — PDCA, building on Walter Shewhart’s work.
- Shook, John. Managing to Learn: Using the A3 Management Process. Lean Enterprise Institute, 2008.
- The Lean Way. “Using the PDCA Cycle to Support Continuous Improvement.” theleanway.net
The A3 layout here is an original design following the common PDCA structure; adapt section names to your organization’s template.