The cause-effect matrix evaluates the level of input influence on CTQ. It allows you to filter input to select the 5 to 10 most influential inputs.
- Copy the Input, in conjunction with the KPOV, into rows by sorting it according to the steps of the Process Map.
- Put the CTQ in a column.
- Identify the weights of the CTQ according to the result of the VOC.
At the intersection of each CTQ with an Input, identify a correlation level via a notation 0, 1, 3 and 9:
- 0: There is no correlation
- 1: Indicates a weak correlation
- 3: Indicates an average correlation
- 9: Indicates a strong correlation
- Team Assessment
- Each note must obtain a consensus
- A review of the whole matrix must be done at the end to smooth out the opinions
For each Input, a score is identified as the sum of the notes products with the weight of the CTQ.
- Scores are close: Review the notes in groups and re-work the notation to bring forward more clearly some Input. If the doubt remains, consider that a score of 235 is no different from a score of 230 or 240.
- Build a Pareto chart.
- Keep the 5 to 10 Input the most important.
- For other Input, set up a gain/cost matrix to select those on which Quick-Wins can be controlled.
Filling the matrix is a process involving common sense experience and a certain quality of judgement. For this reason, the presence of a process expert is necessary. If not, complete the matrix each on its side, then only confront them in groups until consensus is reached.
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J. C. Bongaerts (2008) – Can the Six Sigma method be applied to the process waste generation and treatment
R. Wong (2005) – Project Selection, C & E & FMEA
G. Jing (2006) – Have you found the root cause yet
D. Mokric (2013)-Memory of methodological intelligence
CT Tai (2010) – Using Six Sigma to improve logistics process in a direct selling company
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