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Cause and Effect Matrix

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The Cause and Effect Matrix is a tool which is used to prioritize potential causes identified using a Cause and Effect Diagram or a CTQ Tree.


In this example, the process of doing a load of laundry is being explored. The CTQC's for the process have been identified as:

- Clean clothes
- Clothes smell good
- Wrinkle-free
- No shrinkage
- No dye runs

The input variables that might affect the outcome of the clothes washing process are listed along the left side of the matrix.

When ranking the relationship between the inputs and outputs, the team determined that use of fabric softener would affect how the clothes smell, whether they wrinkle, and how clean they are to some extent. They indicated no relationship between use of fabric softener and shrinkage or dye runs.


CTQC’s are listed along the top of the matrix, then potential causes are listed vertically along the left side of the matrix. The CTQ’s are then ranked in terms of importance. The relationship between causes and effects (CTQC’s) are ranked and an overall score is calculated for the causes.
The causes with the highest overall score should be addressed first in improvement efforts, because they will have the largest impact on the Critical-to-Quality Characteristics.

The practioner should keep in mind that this is a brainstorming tool, used to point the Six Sigma team in the right direction. It should not be confused with "data" , but could be because it makes use of numerical rankings to prioritize the potential "X's".

External Links

Cause and Effect Matrix Tool by -