A3 Thinking: PDCA Problem Solving with Gemba-A3

This guide introduces A3 problem solving and walks you through using Gemba-A3 v2.5 to work through a structured improvement project, from problem statement to results and standardisation.

The A3 is not a form to fill in. It is a way of thinking. The single page is a discipline that forces clarity, evidence, and concision. The process of creating an A3 is where the real learning happens — in the conversations with your responder, in the evidence gathered at the gemba, in the rigour of separating root causes from symptoms, and in the humility of testing countermeasures rather than implementing solutions.

Who is this guide for?

Anyone involved in healthcare improvement — ward managers, laboratory leads, service improvement practitioners, clinical staff, biomedical scientists, and anyone tackling a problem they want to solve properly. No prior lean experience is required. The guide covers the A3 methodology and then provides practical instructions for using Gemba-A3 v2.5.

What you will learn

• →What A3 thinking is and why it matters
• →How the PDCA cycle structures every A3
• →How to classify your problem using the four types of problem framework
• →How to work through the nine sections of an A3 with evidence from the gemba
• →How to use the stage gate to maintain discipline — Plan before Do
• →How to import evidence from Gemba-VSM, Gemba-RCA, and Gemba-SPC
• →How to use the AI Lean Sensei coaching export for guided reflection
• →How to print your A3 as a single-page landscape document for the wall
• →How to save, export, and share your A3 projects

What is an A3?

An A3 is a structured approach to problem solving that captures the entire thinking process on a single A3-sized page (297 × 420mm). Named after the paper, the format imposes a discipline: you cannot waffle on an A3. Every word, every chart, every data point must earn its place. The constraint is the point — it forces you to think clearly, prioritise ruthlessly, and communicate concisely.

A3 thinking was developed as part of the Toyota Production System (TPS) and brought to wider practice as a key lean tool through the book Managing to Learn (Lean Enterprise Institute, 2008). The A3 is much more than a document. Its ultimate goal is not just to solve the problem at hand, but to make the process of problem solving transparent and teachable in a way that creates an organisation of thinking, learning problem solvers.

The PDCA Cycle

Every A3 follows the PDCA (Plan, Do, Check, Act) cycle — sometimes called PDSA (Plan, Do, Study, Act). The A3 is divided into a left side and a right side that map directly to this cycle:

The left side must be completed with evidence before the right side begins. This is not bureaucracy — it is the methodology's immune system against jumping to solutions before the problem is understood. In Gemba-A3, this discipline is enforced through a stage gate (see Section 7).

It Takes Two to A3

A3 thinking is not a solo pursuit. Every A3 has an author — the person responsible for the problem — and a responder — a colleague who coaches the author through the process. The responder does not solve the problem. They ask questions: Is the problem statement specific enough? Have you been to the gemba? How do you know this is the root cause? What evidence supports that?

The responder role can be filled by a manager, a peer, or a lean coach. What matters is that someone is challenging the thinking, not rubber-stamping it. The A3 process gives the manager a tool to mentor others while achieving results. It develops people and solves problems simultaneously.

Building Consensus — Nemawashi

Nemawashi is the practice of consulting stakeholders before proposing a change. In an A3 context, it means sharing your analysis with the people who will be affected by your countermeasures, before you implement them. This is not asking permission — it is building understanding. When people have contributed to the thinking, they own the outcome.

Gemba-A3 includes a nemawashi tracker on the Meta tab where you record who you have consulted, when, and what the outcome was.

Not all problems are the same, and not all require the same approach. The four types of problem framework identifies progressively more complex challenges, each requiring different thinking:

When you create a new project in Gemba-A3, you choose the problem type. This classification cannot be changed once selected — it determines how the sections are labelled and how the coaching prompts are framed. If you are unsure, Type 2 (Gap from Standard) is the right starting point for most improvement work.

This framework is described in detail in Art Smalley's Four Types of Problems (Lean Enterprise Institute, 2018).

This section describes the nine-section A3 process. Section 6 shows how to do each step using Gemba-A3 v2.5.

The Nine Sections

Section Notes

Section 1: Problem Statement

Avoid embedding a solution in the problem statement. "We need a new printer" is a solution. "Specimen labels are printed illegibly 15% of the time, causing re-labelling delays and patient safety risk" is a problem.

Section 5: Root Cause Analysis

The stage gate test applies here: if you remove the root cause you have identified, does the problem disappear? If not, you have found a contributing factor, not a root cause. Keep going.

Section 7: Action Plan Example

Section 9: Standardisation

Standardisation is essential at this stage. Revision of existing policies and procedures to reflect the new way of working, together with a plan to train all staff, ensures the improvement is maintained. Without standardisation, processes drift back to the old way. Include a monitoring and follow-up plan that defines who will check, how often, and what will trigger further action.

Gemba-A3 runs in your browser and can be installed on your phone or tablet for offline use. No app store required.

What you need: A phone or computer with a modern browser. Open https://gembasuite.org/a3 in your browser.

Gemba-A3 has three main tabs: Plan (sections 1–5), Do/Check/Act (sections 6–9), and Meta (project information, nemawashi, and export). A fourth tab, 4C Response, appears only for Type 1 troubleshooting problems.

App Tabs

Creating a New Project

When you create a new A3 project, you first classify the problem type (see Section 3). Choose Type 2 (Gap from Standard) for most improvement work. Enter a title for your A3 — this should be specific enough that someone reading it knows what the problem is.

What Each Section Contains

Each section in the Plan and Do/Check/Act tabs includes the same set of tools:

Section 2: Current State — Pareto Charts

Sections 2 (Current State) and 4 (Waste Identified) include a built-in Pareto chart (see Appendix B for an explanation of Pareto analysis). Enter defect or waste categories and their observed frequencies. Gemba-A3 generates a bar chart with cumulative percentage line, helping your team see the vital few problems that account for most of the impact. The Pareto chart renders correctly in print-to-PDF — including when printed via Chrome — and is included in the printed A3.

Section 3: Goal — SMART Scaffolding

The Goal section includes structured SMART check fields alongside the free-text narrative. Use these to test whether your goal is genuinely Specific, Measurable, Achievable, Relevant, and Time-bound.

Section 4: Waste Identified — DOWNTIME Categories

This section includes structured DOWNTIME waste categories. Tick the wastes you have observed and add evidence for each. If you have imported a VSM, the waste data can be cascaded automatically from your value stream map.

The Do/Check/Act Tab

While the left side (Plan) is incomplete, sections 6–9 are locked behind the stage gate (see Section 7). You can jot timestamped memos on locked sections — capturing thoughts at the gemba that would otherwise be lost — but full editing, photos, and imports are unavailable until the gate is passed.

Section 7: Action Plan

The action plan is a structured list. Each action has a description, named owner, due date, status (not started, in progress, complete, or blocked), and PDCA phase.

Section 9: New A3 from Here

If the A3 has revealed a deeper or different problem, you can create a new A3 project directly from Section 9. The new project inherits relevant context from the current A3.

Printing Your A3

Click "Print A3" on the Meta tab to open a print-ready layout. The nine sections are arranged in the traditional A3 format: left side (Plan) on the left, right side (Do/Check/Act) on the right. Set your printer to landscape orientation and A3 paper size. If printing on A4, use "fit to page."

The printed A3 includes concise text, small thumbnail images, Pareto charts, and a compact action plan table. Full evidence lives in the JSON export — the printed A3 is the thinking on one page.

Gemba-A3 enforces a stage gate between the left side (Plan, sections 1–5) and the right side (Do/Check/Act, sections 6–9). This is the single most important discipline in A3 thinking: you must understand the problem before you develop countermeasures.

How It Works

When you start a new A3, sections 6–9 are locked. Each locked section shows its title and a memo pad for jotting timestamped notes, but no full editing, photos, or imports. Work through sections 1–5 with evidence from the gemba.

When you are ready, tap "I'm ready to move to countermeasures." A confirmation screen shows the checkpoint questions for sections 1–5. Review them. You are prompted (but not required) to confirm that you have reviewed the left side with your responder. Then confirm, and sections 6–9 unlock to full functionality.

Memos on Locked Sections

While sections 6–9 are locked, you can still jot timestamped notes using the memo pad. This resolves a practical tension: A3 discipline says do not jump to solutions, but at the gemba you will inevitably think of countermeasures before the analysis is complete. Write them down. They will not be lost.

After the gate is unlocked, memos are surfaced in a highlighted panel at the top of each section so you can review your early thinking in the context of your completed analysis. Memos are also included in the AI coaching export.

Why the Gate Matters

The most common failure mode in improvement work is jumping to solutions. A team identifies a problem, immediately proposes a fix, and implements it without understanding the root cause. The fix addresses a symptom, the problem returns, and the team concludes that "improvement doesn't work here."

The stage gate prevents this. It is not bureaucracy — it is protection. The discipline of completing the left side before the right side is what separates rigorous A3 thinking from well-intentioned guesswork.

Gemba-A3 is the aggregator in the Gemba Suite. It imports outputs from Gemba-VSM, Gemba-RCA, and Gemba-SPC as evidence within its nine sections. Import keeps the evidence close to where it is used and maintains the source of truth in the originating app.

How to Import

In any section, tap "Import from Gemba app." Select a JSON file exported from another Gemba Suite app. Gemba-A3 reads the file, validates the format, and shows a preview of the data. Confirm to import.

Smart Routing

Gemba-A3 suggests the appropriate section based on the source app. You can override the default and import to any section.

Cascade from VSM

When you import a VSM into the Current State section, Gemba-A3 offers to cascade the waste data into Section 4 (Waste Identified). This populates the DOWNTIME categories with the wastes flagged in your value stream map. You can also select which process steps to include if you do not want the full map.

What Gets Imported

Imported content is read-only within the A3 — you cannot edit the source data. Each import has an annotation field where you add your own commentary explaining why this evidence matters to your A3. Import types include images (VSM maps, fishbone diagrams, control charts), text summaries (validated root causes, observation notes), data tables, and URL links to external documents.

Gemba-A3 generates a structured coaching prompt from your A3 data. Copy it into Microsoft Copilot, Claude, or Google Gemini for guided reflection on your thinking.

How It Works

Click "AI Coach" on the Meta tab or within any section. Choose whole-A3 coaching (reviews the coherent thread from problem to results) or section-level coaching (focuses on one section's evidence quality or readiness to progress).

Coaching Tiers

Gate-Aware Coaching

The coaching prompt adapts to the stage gate state. If the right side is still locked, the AI will not coach on countermeasures or implementation — it focuses entirely on strengthening the Plan sections (see Section 7). This prevents the AI from undermining the discipline that the gate enforces.

Memos from locked right-side sections are included in the coaching export, giving the AI context about early thinking without treating those thoughts as formal analysis.

Project Management

The dark project bar below the header manages multiple A3 projects. Each project stores its own metadata, section content, photos, imports, memos, and revision history. Data auto-saves as you work.

JSON Export

Click "JSON" to download a complete backup of your A3 project. The file contains everything: metadata, all nine sections with text, photos, imports, memos, revision history, action items, Pareto data, DOWNTIME waste data, SMART check fields, nemawashi records, and stage gate state. Re-import on any device.

When to export

After every working session. Before switching devices. Before clearing your browser. Before deleting any project. Keep your JSON files in a folder on your computer or cloud drive — they are small and contain everything.

Printing

Click "Print A3" to open a landscape A3-formatted print layout. The nine sections are arranged in the traditional A3 format. Set orientation to landscape and paper size to A3 (or "fit to page" on A4).

Importing

Click "Import" to load a previously exported JSON file. Creates a new project — never overwrites existing data.

Further Reading

Managing to Learn: Using the A3 Management Process to Solve Problems, Gain Agreement, Mentor, and Lead. Lean Enterprise Institute, 2008. The definitive guide to A3 thinking, showing how the process develops people and solves problems simultaneously through the author/responder coaching relationship.

"Toyota's Secret: The A3 Report." MIT Sloan Management Review, Summer 2009. A concise introduction to A3 thinking with a worked example showing how a mentee learns through progressive iterations of an A3 under coaching.

A3 Thinking Workbook. NHS Improvement / Phoenix Consultancy. The stage-gate process, checkpoint questions, and section structure used in Gemba-A3 are based on this workbook. Essential companion for NHS teams.

Bringing Lean to Life — Making Processes Flow in Healthcare. NHS Improvement Diagnostic Team. Practical coverage of A3 thinking, VSM, standard work, and continuous improvement in healthcare settings.

Four Types of Problems. Art Smalley, Lean Enterprise Institute, 2018. The problem classification framework used in Gemba-A3's project creation gate.

Toyota Kata: Managing People for Improvement, Adaptiveness and Superior Results. Mike Rother. The coaching kata and improvement kata that underpin the responder role in A3 thinking.

"Quality Improvement in Basic Histotechnology: The Lean Approach." Virchows Archiv, 2015. Lean transformation in histopathology including A3 problem solving with measurable results.

Online Resources

Lean Enterprise Institute (LEI) — www.lean.org
Lean Enterprise Academy — www.leanuk.org

Type 1 problems are troubleshooting situations: something has gone wrong, a known standard is not being met, and the situation needs immediate attention. The full nine-section A3 is not the right tool here — the problem is urgent and the standard already exists. What is needed is a rapid, structured response that contains the issue, corrects it, confirms the fix, and communicates what happened.

Gemba-A3 provides a 4C Rapid Response mode for Type 1 problems. When you select Type 1 during project creation, a dedicated 4C tab appears instead of the full Plan and Do/Check/Act tabs. The four Cs are:

A Pareto chart is a bar chart that shows the relative frequency or impact of different categories, arranged from most significant to least significant, with a cumulative percentage line overlaid. It is based on the Pareto principle — the observation that roughly 80% of effects come from 20% of causes.

In improvement work, a Pareto chart helps you identify the vital few problems that account for most of the impact, so you can focus your A3 on the problem that matters most rather than trying to fix everything at once.

How to Read a Pareto Chart

The bars show the count or frequency of each category, arranged from tallest to shortest (left to right). The cumulative percentage line rises from left to right, showing what proportion of the total each category contributes. The point where the cumulative line crosses 80% tells you which categories make up the vital few.

Example: Specimen Labelling Errors

A laboratory team observed 87 labelling errors over four weeks and categorised them:

The Pareto chart shows that the first two categories — wrong patient ID and illegible print — account for 66% of all errors. Adding the third category (missing specimen type) reaches 82%. These are the vital few. The A3 should focus on these three causes rather than attempting to address all six simultaneously.

In Gemba-A3, sections 2 (Current State) and 4 (Waste Identified) include a built-in Pareto chart generator. Enter your categories and counts, and the tool draws the chart with the cumulative percentage line. The chart is included automatically in the printed A3 output.