The cause and effect matrix (also called C & E matrix) helps you decide which inputs from a Cause and Effect fishbone diagram should be tackled / addressed first. All the causes of the problems from the fishbone diagram may not be of equal value. The Cause and Effect (C & E) matrix provides a way of mapping out how value is transmitted from the input factors of your system (the Xs) to the process or product outputs (the Ys). With these relationships visible and quantified, you can readily discover the most-influential factors contributing to value.
Procedure for drawing Cause and Effect matrix-
- List down the inputs and outputs.
Inputs- The listing of inputs should come from a previously completed process flow map or value stream map or a fishbone diagram.
Outputs- The list the multiple outputs (the Ys) of the process or product across the columns of the matrix. Sometimes there is only a single output, but you usually have to simultaneously achieve several outputs, such as a performance level, a cost target, and a maximum cycle time.
- Add weight to each input and output
Analyze and quantify the relationships between each listed input and each output by placing a relationship score (on a scale of 0 to 9) at the matrix intersection of each row and column. Strong Cause and Effect relationships are scored as 9s; moderate Cause and Effect relationships get 3s; weak relationships are 1s; and having no relationship means a score of 0.
- Summarize and figure the final score
Multiply each score of X(cause) with score of Y (effect). Add the final score of each cause. The cause having the highest score is most responsible for the particular Y ( effect or problem)
- Perform the pareto analysis- Perform a pareto analysis (a separate chapter for the full procedure of pareto analysis will be given later in this book). Pareto analysis is based on 80-20 principle which suggests that 80% of the result (effect) is caused by 20% of the problems. These 20 % of the most important causes must hence be eliminated first. For information on pareto analysis and free excel template click Pareto analysis.