Problem solving

A3 problem solving

In French: Méthode A3

The A3 method holds a complete line of reasoning — background, current situation, causes, countermeasures, plan, follow-up — on a single A3-size sheet, whose space constraint is the main tool.

The flow of the sheet

The sheet is read in two columns. On the left, what is established: the background, the current situation with figures, the target aimed for, the cause analysis. On the right, what is decided: the countermeasures, the plan with its owners and dates, then the follow-up of results.

The left column legitimately takes up more than half the work. An A3 whose analysis part fits in three lines and whose action plan takes half the sheet signals a line of reasoning that jumped from the problem to the solution.

The last box, the follow-up, is the one filled in least and the one that distinguishes an approach from an intention. It carries the measurement afterwards, and therefore the answer to the only question that counts: did it produce the expected effect.

The space constraint is the tool

The format is not a layout convention: it is what forces choices. On one sheet, not everything can be written, so one has to decide what is essential — that trade-off is the work itself.

That constraint also acts on reading. A line of reasoning that fits before the eyes in one go is really discussed in a meeting, whereas a twenty-page document is skimmed and approved without being examined.

It finally imposes charts rather than text. A before-and-after curve, a cause diagram, a histogram take little space and are read fast — the format pushes towards representation, which is also the most honest way of showing a situation.

What the sheet is used for

It serves first as a medium for dialogue between the person leading the subject and their manager. The document is built through back-and-forth, and each exchange bears on what is missing from the reasoning rather than on the progress of the schedule.

That is what makes it a skills development tool as much as a problem-solving tool. The manager does not give the answer: they point to the place where the demonstration does not hold, and let the person leading the subject go and find out.

It finally serves as memory. A filed sheet keeps the complete reasoning of a problem that was treated, which no meeting minutes do — and makes it possible, two years later, to know what was tried and why.

The common mistakes

Treating the format as a template to fill in. An A3 filled in box by box, with no back-and-forth with a manager, produces a compliant document and a line of reasoning never put to the test.

Writing the current situation without a figure. "The lead time is too long" makes it possible neither to set a target nor to observe progress; it is the point where most sheets lose their value.

Leaving the follow-up box empty. It turns an action plan into an approach, and its absence explains most of the A3s nobody can say whether they succeeded.

On the shop floor — Automotive parts supplier

A first version devoted five lines to the analysis and the rest to a plan of twelve actions. The manager sent the sheet back with a single question: what does the link between the cause put forward and the problem rest on. The second version had three actions, only one of which was enough.

The other tools illustrated by this trade: automotive.

Frequently asked questions

Is the A3 format compulsory?

The physical format matters less than the constraint of a single page, readable at one glance. What counts is the obligation to choose what deserves to be on it: a document that spreads over several pages loses exactly what makes the value of the method, and becomes one report among others again.

Who writes the A3?

The person leading the subject, alone, with the help of the people who know the shop floor. An A3 written by an outside expert then handed to the team removes all the learning and does not survive their departure. The manager steps in by questioning the reasoning, never by writing in their place.

What is the difference between an A3 and a project report?

The report describes what was done; the A3 demonstrates why what was done had to be. The difference shows in the space taken up by the analysis: in a report, it is summarised in the introduction, whereas it makes up more than half of an A3. That is also what makes one debatable and the other merely approvable.

How long does it take to produce one?

A few weeks for a real problem, most of the time being devoted to establishing the current situation and checking the causes on the shop floor. A sheet produced in two hours is a sheet where everything was assumed — which is spotted immediately by the absence of figures in the left-hand part.