This article is the third in a four part series to show you “How to Complete a Six Sigma Root Cause Analysis.” The series covers four tools:
In this article, we will be discussing the C&E Matrix.
A Cause and Effect Matrix is a tool to help the Six Sigma Project Team prioritize the X’s or Process Inputs. The Cause and Effect Matrix relates Process Steps to Process Inputs (X’s) and correlates the Inputs to Process Outputs. In a C&E Matrix, Customer Requirements (or Y’s) are ranked by order of importance to the Customer. The Inputs (X’s) and Outputs are rated by their Interaction Impact. The Cause and Effect Matrix should determine what Key Process Input Variables (KPIV’s) should get the most attention.
Step #1: Enter the Customer Outputs (Y’s).
These Outputs comes from the “O” (Output) in the SIPOC. There should be no less than three Outputs under the “O” in the SIPOC(R); therefore there will be no less than three Outputs in the Cause and Effect Matrix.
Step #2: Rate the Importance of the Process Outputs to the Customer.
Use a 1-10 Ranking with 1 being the least important and 10 being the most important.
Step #3: List the Steps of the Process.
These are found on the Input Map. Repeat the steps for the amount of Process Inputs for that Step. For example, the step “Setup” in this example has five inputs so we repeat “Setup” in five rows.
Here is an example of the Input Map where the “Process Steps” and “Process Inputs” are found:
Step #4: List the Inputs for all of the Steps in the Process.
These are found on the Input Map (example above). Do not leave blank rows in between each step. For example, the input “Lighted Area” for the step “Setup” should not have a blank row below it separating the input “Lighted Area” for the step “Setup” from the input “Sandwich Maker” for the step “Apply the Peanut Butter.” Make sure each row and column are filled in.
Step #5: With the SME’s (Sublect Matter Expert’s or Process Owners), determine the Correlation Scores
The Correlation Scores are 0,1,3 and 9. Do not use a 1-10 rating. Using a 1-10 rating allows the project team to “ride the fence” on Inputs that cause debate and the project team will compromise with the score of “5.” This will defeat the purpose of the C&E Matrix.