## Six Sigma X-Y Matrix Explained

written by: Suvo โข edited by: Marlene Gundlach โข updated: 7/13/2009

X-Y matrix, a project management tool, is also called cause and effect (C&E) matrix. This article will explain six sigma X-Y matrix project management tool and includes an example.

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X-Y matrix project management tool (or cause and effect matrix) is used mainly in six sigma DMAIC project. This is the ideal tool for prioritizing the input process parameters (Xโs). The prioritization of Xโs is important for performing process FMEA.

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### Procedure for Making an X-Y Matrix

• List out the CTQ (Yโs) for the targeted process.
• Make a table with numbers of rows and columns.
• Write down the CTQ against individual column.
• Write the weightage for each CTQ.
• Find out input process parameters (Xโs) by brainstorming and write them against individual rows.
• Put suitable numbers in the intersection of rows and columns to show the relationship between Xโs and Yโs.
• Finally calculate the weighted sum against each Xโs.

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### An Example

Letโs take the example of the newspaper printing process. After transforming the VOC we find the CTQ (Yโs) as below:

• Good quality photo
• Harmless to health

Upon brainstorming, the input process parameters (Xโs) have been found as below:

• Good quality ink
• Less vibration during operation of printing press
• Paper quality

For the above sets of Xโs and Yโs the X-Y matrix table will look like the example below:

Wherever there is a strong relation between Xโs and Yโs, put 9. For weak relations put 3 or 1. Keep the intersection field blank if there is significant relation.

Weighted sum for โGood quality ink" is calculated as 15*9 + 10*9 + 10*1 = 235. The calculation is similar for the rest of the Xโs. The input parameters with a higher weighted sum should be selected for further FMEA.

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### Conclusion

A X-Y matrix project management tool is useful for prioritizing the input parameters (Xโs). CTQ (Yโs) of the six sigma project must be kept ready before preparing the cause and effect matrix. The X-Y matrix should be prepared by brainstorming of cross functional team members.The success of FMEA also depends upon the result of X-Y matrix.