3C List

Introduction: 3C List

A 3C List is a simple Lean tool to capture and solve issues. Each item is logged under three headings. Concern, Cause, and Countermeasure. It gives teams a clear line of sight from the problem to the fix and helps track progress in a visual way.

Background

The 3C approach grew within Toyota style daily management to support fast problem solving at the gemba. It links well with Kamishibai audits and team huddles where leaders review open concerns and agree the next steps. Unlike long reports, a 3C entry fits on one line or one card. This keeps the focus on action and learning.

Key Elements or Features

• Concern. State the problem in plain words. Include where and when it occurs and the impact on safety, quality, delivery, cost, or morale.
• Cause. Record the most likely root cause after quick fact finding. Use checks like 5 Whys, simple graphs, and visual inspection.
• Countermeasure. Define the specific action to remove or control the cause. Include who will do it and by when.
• Status and evidence. Mark each item as open, in progress, verified, or closed. Attach a photo, chart, or check result as proof.
• Ownership and cadence. Assign a clear owner. Review items at the daily huddle and escalate if a due date is missed.
• Visual control. Keep the list visible near the work. Use colours or symbols to show priority.

Applications or Examples

• Production line defects with a quick fix and a follow up to prevent repeat.
• Clinic flow delays with checks on room readiness and handover timing.
• Service backlog items with a small change to forms or queue rules.
• Warehouse picking errors with a layout or labelling change.

Relevance or Impact

A 3C List builds discipline in problem solving. Teams react faster, hold gains, and learn from each issue. Leaders see risk early and can remove barriers. The method supports standard work and continuous improvement.

See also

• Kamishibai
• A3 Problem Solving
• Visual Control
• Daily Stand-Up