2.7.1 Drawing a multiple-cause diagram
We can draw a multiple-cause diagram to explore and to communicate the complexity of a system, and to recognise that the effect of a particular system is normally the result of a number of different causes.
Examine the example shown in Figure 17 of the multiple causes of poor sales performance from a team.
The first task in drawing such a diagram is to identify the output in which you are interested. Generally we take a single output or effect and examine the several causes leading to it. We could try to draw a multiple-cause diagram for two or more effects but the diagram would quickly become impossibly complex.
Having identified the effect we are exploring, we then add the first, or primary, causes of that effect. In this case, we have established two primary causes. These are lack of sales literature and poor effort. We then consider each of these and add their causes. Three causes of poor effort are shown in the diagram. We then move backwards through the different levels of causes until we are satisfied that we have a comprehensive diagram to explain the multiple causes of the poor sales performance.
Box 5: Important points about multiple-cause diagram
We are examining the multiple causes of a single output, so all arrows lead along a path to the output.
There needs to be a logical cause and effect relationship between each link. For example, the link between low earnings and lack of knowledge of sales work may not be clear, and another element such as high staff turnover could be included in the path.
A single cause can have a number of effects. An example in the diagram is low earnings that lead to lack of knowledge of sales work and to low job satisfaction. Often these points are the key ones to address: an improvement (on low earnings) will lead to multiple benefits.
Consider how the diagram can be developed to make it more effective. Important paths can be highlighted — perhaps the lines can be coloured or made thicker. Key elements can be underlined or bordered.
Drawing multiple-cause diagrams helps in exploring and in communicating complex issues. Practice improves drawing skills and deepens understanding. Draw one today!