KaizenProof

Lesson 11 of 23 · 8 min read

One problem on one page: A3 thinking for office work

In Lean: A3 thinking

Builds on: Write the problem down before solving it, The 5 Whys in depth

In one minute

A3 thinking means telling the whole story of one problem on a single page: why it matters, what is happening, what causes it, what will change, and how you will know whether the change held. The page is not a form to complete but a way to test your own reasoning, because each part has to follow from the one before. The one-page limit forces you to keep only what matters. It is written by the person who owns the problem and improved by talking it through with the people it touches.

The idea

The name comes from a paper size, twice an A4 sheet. The paper is not the point; the discipline is. On a sheet, in a document or on a whiteboard, the page tells a story in a fixed order, and a reader should be able to follow it in a few minutes.

What each part is for

The left half is about understanding; the right half is about acting.

  1. Background. Why this problem, why now, and who it affects. Two or three lines that tell a reader why it deserves attention.
  2. Current state. The problem statement from lesson 9, with its "should" as the target, and what you saw when you went to look in lesson 8: a rough sketch of the steps, where the work waits or goes wrong, what you counted. This is the heart of the page. If it is thin, everything after it is a guess.
  3. Cause. The why-chain from lesson 10, each branch with what was checked.
  4. Countermeasure. What will change, each change tied to a cause on the page, who does it and by when. Removing a step comes before anything else, as in lesson 6.
  5. Check. What you will look at, when, and what would tell you the change held, partly held or was reverted. Agree it before the change starts.
An A3: one problem on one pageThe left half is about understanding the problem; the right half is about acting on it. Each part should follow from the one before.
The layout of an A3 sheetThe layout of an A3 sheet: a title across the top, then two halves. The left half, understand, holds 1, Background: Why this problem, why now, and who it affects; 2, Current state: What should happen, what happens, and what you saw when you looked; 3, Root cause: The why-chain, each link checked against the work . The right half, act, holds 4, Countermeasure: Each change tied to a cause; remove a step before adding one; 5, Plan: Who does what by when, and the prediction you will check; 6, Follow-up: Checks at about a week, two weeks and a month: held, partly, reverted . The story reads from top left to bottom right.Title: the problem, in a few plain wordsUnderstandAct1BackgroundWhy this problem, why now, andwho it affects2Current stateWhat should happen, what happens,and what you saw when you looked3Root causeThe why-chain, each link checkedagainst the work4CountermeasureEach change tied to a cause;remove a step before adding one5PlanWho does what by when, and theprediction you will check6Follow-upChecks at about a week, two weeksand a month: held, partly, revertedThe layout of an A3 sheetThe layout of an A3 sheet: a title across the top, then two halves. The left half, understand, holds 1, Background: Why this problem, why now, and who it affects; 2, Current state: What should happen, what happens, and what you saw when you looked; 3, Root cause: The why-chain, each link checked against the work . The right half, act, holds 4, Countermeasure: Each change tied to a cause; remove a step before adding one; 5, Plan: Who does what by when, and the prediction you will check; 6, Follow-up: Checks at about a week, two weeks and a month: held, partly, reverted . The story reads from top left to bottom right.Title: the problem, in a fewplain wordsUnderstandAct1BackgroundWhy this problem, why now, andwho it affects2Current stateWhat should happen, what happens,and what you saw when you looked3Root causeThe why-chain, each link checkedagainst the work4CountermeasureEach change tied to a cause;remove a step before adding one5PlanWho does what by when, and theprediction you will check6Follow-upChecks at about a week, two weeksand a month: held, partly, reverted
  • Some teams fold the plan into the countermeasure. What matters is that every change answers a cause on the page.

A way of thinking, not a form

Read the page from top left to bottom right and ask at each part: does this follow from what came before? A countermeasure that answers no cause on the page is a fix looking for a problem. A cause with no evidence in the current state is an opinion. The page exists to make gaps like these visible while they are still cheap to fix.

The author is the person closest to the problem, not a specialist writing on their behalf. The draft is shown early to the people who do the work and the people the change will affect, and it changes as they point out what is missing. Several rounds are normal. A manager helps most by asking questions such as "what did you see?" and "how do you know that is the cause?", not by approving or rejecting the page.

If the story will not fit on one page, the problem is probably too big. Split it. Lessons 12 to 15 go further into the right half.

Example

Illustrative example, not a real company.

The payslip problem from lesson 10, on one page:

  • Background: each corrected payslip means an employee paid wrongly and an extra payroll run; managers have started asking why.
  • Current state: payslips should be right first time. In the last three runs, fourteen were corrected after payday. Following the changes showed six arriving after cut-off and eight keyed from emails that could be read two ways.
  • Cause: branch A, the cut-off date moves monthly and is on payroll's own calendar only; branch B, there is no form for salary changes, so any wording is accepted. Checked against all fourteen.
  • Countermeasure: the team first asked whether reading free-text emails should exist as a step; it should not. Managers submit changes on a short form with required fields instead. The year's cut-off dates go into the managers' shared calendar. The payroll lead owns both, before the next run.
  • Check: at each of the next three runs, count payslips corrected after payday and note whether any came from a late or unclear change. Decide at the third run: held, partly held or reverted.

A payroll specialist wrote it, showed it to two managers and a colleague, and changed the form after they pointed out that bonuses needed a field of their own.

Common mistakes

  • Writing the right half first. Choosing the fix, then filling in the left half to justify it. The boxes look complete and prove nothing.
  • Treating it as a report for approval. An A3 supports a conversation: drafted early, changed often, never submitted once and filed.
  • Cramming. Small print and several problems on one sheet hide the story. One problem, few words.

Words to know

  • One problem on one page (in Lean: A3 thinking): a problem's story, from background to check, kept to one page.
  • Understand first, then act (in Lean: the left and right halves of an A3): current state and cause before countermeasure and check.

Check your understanding

3 questions. Answer them all, then check. You can try again as often as you like; nothing about your attempts is kept.

Question 1 of 3Put the parts of an A3 in the order a reader meets them.

Put the steps in order, first at the top. Use the Up and Down buttons.

  1. Position 1: Current state: the gap, and what was seen.
  2. Position 2: Cause: the checked why-chain.
  3. Position 3: Check: what will show whether it held.
  4. Position 4: Countermeasure: what will change, who, by when.
  5. Position 5: Background: why this problem, why now.

Question 2 of 3Three A3 drafts. In which one has the reasoning broken?
Question 3 of 3A manager receives an A3 from a team member. What helps most?

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Try it on your own work

Describe one recurring task that wastes your time, and see these ideas applied to it.

Report a friction (opens in a new tab)

Worksheet for this lesson: A3 Problem Solving Template (free download, no sign-up).

Where this comes from

Setting out a problem and its countermeasure on a single large sheet is a practice that grew up at Toyota as a way of developing people's problem solving and of reaching agreement; Lean practitioners later carried it into offices and services.