The Cause and Effect Matrix is a tool which is used to prioritise potential causes by examining their relationship with the CTQs. CTQ’s are placed on the top of the matrix and causes are place along the left side. The CTQ’s are ranked in terms of importance. The relationship between the causes and CTQs are ranked. An overall score is calculated and the cause with the highest overall score should be addressed first because they will have the largest impact on the CTQs.
- List the CTQs across the top of a matrix.
- Rank and assign scores to each CTQ according to its importance to the customer.
- List the causes on the left side of the matrix.
- Determine correlation scores between each cause and CTQ based on the strength of their relationship (E.g. 1 – weak, 3 – some, 9 – strong).
- Cross multiply correlation scores with priority scores and add across for each cause.
- Create a Pareto chart and focus on the causes with the higher overall scores.