Lean Manufacturing and Six Sigma Definitions

Glossary terms, history, people and definitions about Lean and Six Sigma

C4

C4 (also written as C-4) is a method of problem solving similar to the PDCA cycle, but describes the Plan step more clearly.

It was developed by David Veech (with help from Mike Kirkby) to provide guidance to A3 templates and assist with developing people as problem solvers. It is used in conjunction with quality circles and improvement teams.

The 4 C’s stand for:


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  • Concern – Describe the current situation or problem that the team wants to resolve using data
  • Cause – Identify all causes of the problem, using a fishbone diagram, and prioritize which ones to pursue
  • Countermeasure – Identify a short-term action that may correct the root cause of the problem
  • Confirm – Ensure that the countermeasure was successful, and implement any long-term countermeasures

The C4 card is used for small, daily improvements that are easier to solve, but still need a problem solving process to follow (see below)

C4 card described in the book, The C4 Process: Four Vital Steps to Better Work

The C4 worksheet is used for more challenging problems performed as a team, using the A3 one-page format structure.

C4 worksheet described in the book, The C4 Process: Four Vital Steps to Better Work

Books