--- name: a3 description: "Structured problem solving on one page: background, a Pareto-driven root cause chain, and a tested countermeasure tracked against a target, actual, gap and standard (TAGS) scorecard. Use when: A specific, bounded problem with a measurable gap between current and target performance. You can gather real data or direct observation about the current condition — not just an impression of it. You want a record that survives past the meeting it was written in. Not for: The \"problem\" is really a choice between options with no current-state gap to close — that calls for a decision tool, not an A3. You don't have — and can't get — any real data or observation. Go and look first; don't fill the page in from memory. The scope is bigger than one person or team can move in a matter of weeks — that's Hoshin-level work, not an A3." --- # A3 problem solving Structured problem solving on one page: background, a Pareto-driven root cause chain, and a tested countermeasure tracked against a target, actual, gap and standard (TAGS) scorecard. Family: Problem solving / root cause analysis · Format: .xlsx · Domain: core ## What it is An A3 is a single page that walks a problem from background through root cause to a tested countermeasure and its results — named after the paper size it was originally constrained to. The one-page limit is a discipline, not a formatting quirk: it forces you to separate what matters from what doesn't before anyone reads it. But an A3 is more than a form. At Toyota, where the approach comes from, it's a mentoring and problem-solving dialogue: the author drafts it, a coach or manager asks questions about each section (have you seen this first-hand? how do you know that's the cause?), and the author goes back to look and rewrites. The page records how the thinking developed, and the conversations are where people learn to solve problems. There's no single official layout. This tool's version tracks the key metric in a TAGS box — Target (the goal you're committing to), Actual (the latest measured value), Gap (target minus actual) and Standard (the baseline or specification you're measured against) — as its scorecard for proving the problem is real and later proving it's fixed; that box is this tool's convention, not something every A3 has. It also uses a Pareto breakdown that earns the right to chase one root cause instead of guessing at all of them. Sources: John Shook, Managing to Learn (Lean Enterprise Institute, 2008); Durward Sobek and Art Smalley, Understanding A3 Thinking (2008). ## When to use it Use it when: - A specific, bounded problem with a measurable gap between current and target performance. - You can gather real data or direct observation about the current condition — not just an impression of it. - You want a record that survives past the meeting it was written in. Not when: - The "problem" is really a choice between options with no current-state gap to close — that calls for a decision tool, not an A3. - You don't have — and can't get — any real data or observation. Go and look first; don't fill the page in from memory. - The scope is bigger than one person or team can move in a matter of weeks — that's Hoshin-level work, not an A3. ## How to fill it in - **background** — State the problem in plain terms and say why it matters now — a metric that's off target, a complaint, a near-miss. One paragraph. If you can't say why this matters in one paragraph, you don't understand the problem well enough yet to write the rest of the page. - **problemStatement** — One or two sentences, separate from the background: the specific, bounded gap you're closing. Background is why it matters; the problem statement is exactly what's broken. If the two read identically, the problem statement is still too vague. - **metric** — Give the Standard (the baseline or spec this is measured against), the Target (the end-state goal), and a dated Actual series showing the trend. Actual and Gap should never be typed in by hand as static numbers — Actual is just the latest point in the series, and Gap is Target minus that point, so they stay correct as the series updates. - **pareto** — Break the problem into categories and rank them by count, cost, or impact — pick the axis deliberately, because counting frequency when cost or customer impact is what actually matters is the single most common way Pareto analysis misleads. Chase the category that dominates, not the one that's easiest to fix. If that category is still broad, break it down one level further (L2) rather than moving on to the second-place category. - **fiveWhys** — Start from the Pareto's vital-few category, not the problem in general, and ask why, repeatedly, following the strongest evidence at each step rather than the most convenient answer. Stop when you reach something you can actually act on — typically 3 to 5 whys deep. If the last why is "people weren't careful enough," you stopped one step too early. - **countermeasures** — Each countermeasure must trace to the stated root cause, not just address the symptom. Name an owner and a due date for each — a countermeasure without an owner doesn't happen. - **effectConfirmationPlan** — Decide before you act how and when you'll check the metric again — which cadence, over what period, against which of Target or Standard. This is where most A3s go soft: "monitor results" is not a confirmation plan. - **followUpActions** — Capture what has to happen to make the fix stick — standard work updates, training, wider rollout. This is what separates a one-time fix from a sustained improvement. ## What good looks like The example below is a full worked A3 as this tool lays it out: a TAGS scorecard and trend chart showing a real, quantified gap; a Pareto breakdown — including a second-level stratification of the dominant category — that earns the root cause chain rather than assuming it; a causal chain that ends in something actionable; countermeasures that each name the cause they address; and a confirmation plan set before the fix went in. Full worked example, on-screen and as a downloadable .xlsx: https://www.katafacts.com/katas/a3 ## Common mistakes - **Root cause is "not enough training" or "people weren't careful."** — Almost always means the why-chain stopped one step early. Ask why the training or attention wasn't there in the first place — usually a system or standard-work gap, which is something you can actually fix. - **The Pareto is ranked by frequency when cost or customer impact is what actually matters.** — A high-frequency, low-cost category can dominate a frequency-ranked chart and pull attention away from the few events that are doing the real damage. Choose the axis on purpose, and say which one you chose. - **Countermeasures aren't linked to a specific cause.** — A grab-bag of good ideas with no causal link fixes the mood in the room, not the problem — and afterward you can't tell which one, if any, actually worked. - **Current condition is written from memory instead of data or direct observation.** — An A3 built on an impression inherits every bias in that impression. Go and see, or pull the data, before writing this section. - **Writing the A3 alone and handing it in as a finished form.** — The value of an A3 comes from the back-and-forth with a coach or manager who questions each section and sends you back to check. An A3 nobody challenged is usually a first draft of someone's assumptions — share it early, while it can still change. - **Target and Standard are treated as the same number.** — Standard is the baseline or spec you're measured against; Target is the goal you're committing to. Collapsing them hides whether you're trying to get back to acceptable or push past it. ## What it connects to Upstream: - **Pareto chart** (`pareto-chart`) — Feeds the A3's root cause section directly — it's what earns the right to chase one category instead of guessing. A standalone Pareto worksheet is useful when the category breakdown needs more room or more data than the A3 page allows. - **5-Whys** (not in the catalogue yet) — The root cause analysis section runs a 5-Whys inline, starting from the Pareto's vital-few category. A standalone 5-Whys worksheet earns its keep when the causal chain needs more room than the A3 page allows. - **Fishbone diagram** (not in the catalogue yet) — Use one first when there are several plausible cause categories to sort through before the Pareto data is clean enough to rank confidently. Downstream: - **Countermeasure matrix** (not in the catalogue yet) — When an A3 surfaces more candidate countermeasures than fit cleanly on one page, rank them by impact and effort there before committing. - **Run / control chart** (not in the catalogue yet) — The TAGS trend chart is a lightweight run chart. Once a countermeasure is live, a full run or control chart tracks whether the new process is actually stable at the new level, not just briefly better. - **PDCA record** (not in the catalogue yet) — An A3's effect-confirmation and follow-up sections are one turn of PDCA. Use a PDCA record to track further cycles if the first countermeasure doesn't fully close the gap. ## Where AI helps Judgement — stays with you: - Deciding which root cause is real, not just plausible - Choosing the Pareto axis — frequency, cost, or impact — for this specific problem - Committing to a target condition and owning it - Judging whether an experiment's result actually closes the gap Analysis — AI helps: - Pressure-testing a why-chain for gaps or unjustified leaps - Flagging when a Pareto ranking looks misleading for the stated axis - Drafting a first-pass background and problem statement from raw notes or data - Checking that every countermeasure traces to a stated root cause Drudgery — automated: - Computing Gap from Target and the latest Actual, every time the series updates - Formatting the page and keeping it to one sheet - Rolling owner and due-date fields into a tracked action list - Exporting to xlsx (and pptx for report-outs) in the house format --- A3 problem solving is licensed [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Attribution: Katafacts (katafacts.com). ## Using this skill Apply this method as part of whatever broader task, instructions, or deliverable you're already working on -- it's a method to use, not a standalone conversation to start. There is no generation tool for this catalogue yet, so draft the artifact's actual content yourself, following the fields above, the same way a person filling this out by hand would. The canonical guide page and a downloadable worked example (.xlsx) are at https://www.katafacts.com/katas/a3.