A3 problem solving report: theory, step-by-step guide and case study

Theory: thinking on one sheet

The A3 report comes from Toyota, named after the paper size. It is less a form than a way of thinking: the author must understand the problem well enough to explain it on one page, and the page becomes the basis for discussion with the team and management. The left side describes the problem (background, current condition, goal, analysis), the right side the solution (countermeasures, follow-up, results).

A3 follows the PDCA cycle: Plan (sections 1 to 5), Do (implementing countermeasures), Check (follow-up and results), Act (standardise or start again).

Step by step

1. Background: one paragraph on cost, customer impact or safety.
2. Current condition: numbers and a chart, for example a Pareto of scrap.
3. Goal: target value and date.
4. Root cause: fishbone and 5 Why; note how each cause was verified.
5. Countermeasures: one or more per root cause, with owner, date, status.
6. Follow-up: what is checked, how often, by whom.
7. Results: before and after, with charts or photos.

Case study: scrap on shaft line 3

The Load sample A3 shows a typical internal project.

• Background: scrap on line 3 cost 42,000 EUR in six months, twice the plant target; two customer complaints about oversize bearing seats.
• Current condition: scrap 3.8 % (target 1.5 %). Pareto: scratches 33 %, dents 21 %, wrong dimension 12 % but 45 % of the scrap cost. Cpk of the bearing seat 0.92.
• Goal: scrap below 1.5 % and Cpk ≥ 1.33 by 15 December.
• Root cause: offset not entered after insert change (verified by trial); scratches from parts touching in transport boxes (verified on one shift).
• Countermeasures: automatic probing, boxes with separators, SPC every 20 parts.
• Results: October 1.9 %, November weeks 1–2 1.3 %; Cpk 1.62.

Common mistakes

• Writing the solution in the background section before the analysis.
• No numbers in the current condition.
• Countermeasures that do not link to a root cause.

Frequently asked questions