NEW 7 QC TOOLS

Relations Diagram

Purpose

The purpose of relations diagram is to generate a visual representation of the relations between an effect and its causes as well as the interrelationship between the causes in complex problems.

Structure

As mentioned in the opening paragraph of the chapter, the structure of relations diagram is not very rigid; it is quite flexible. Only thing fixed about the diagram is a bold bordered rectangle in which the ‘effect’ is written. The causes are entered in light rectangles and lines are drawn to show relation between the rectangles. The lines have arrows at one end showing which is the cause and which is the effect - the arrow always leading from the cause to the effect. The most common shape the diagram takes has the ‘effect’ at the centre, with immediate causes surrounding it and secondary and tertiary causes as outer layers. Diagram 1 shows one such representation.

The most common structure of relations diagram seen in diagram 1, where the effect is placed at the centre and the causes surround it, is called ‘Focused Counterpoint’ type. When the interrelations between the immediate causes is more widespread, it may be difficult to connect the rectangles located on either side of the effect. In such cases the effect may be placed on the top or the left hand side of the diagram and causes below or to the right of the effect. The diagram then resembles organization charts. The flow of arrows in such a diagram is in only one direction bottom to top or right to left. Diagram 2 shows a ‘Unidirectional’ type of structure.

These two diagrams have shown how the structure of relations diagram is extremely flexible.

The shape depends on the nature and extent of interrelations between various causes. The team is free to arrange the rectangles with causes in any convenient shape. If need be, the shape is recast with rearrangement of the causes for ease of connecting the rectangles.

Procedure

To prepare a relations diagram, there is a need for a large number of causes. No single individual can generate an exhaustive list of causes. Hence the tool gives best results when it is used in a group. The group must brainstorm the subject to get the maximum number of causes. The steps in the preparation of a relations diagram are :

1. Decide the ‘effect’ or the problem for which causes are to be found. Write is in the centre of the flip chart or a board and enclose it in a dark bordered rectangle. Discuss the subject and confirm the ‘effect’.
2. Brainstorm to identify the immediate causes for the effect first. Enter these in rectangles around the central dark rectangle. Take care to place causes likely to be related to one another in adjacent positions. It is quite possible that the locations of the causes may have to be changed as one progresses. Hence a white board is preferable to a flip chart for this exercise. If a flip chart is used, the causes may be written on post-it pads and stuck on the chart so that their location can be changed easily.
3. Connect these immediate causes to the effect by connecting the rectangles of the causes to that of the effect with a line with an arrow pointing towards the effect. Explore the cause and effect relationship among the immediate causes and connect them, keeping in mind that the arrow always points to an effect.
4. Taking each of these immediate causes as an effect, brainstorm to find causes for them one by one. The key question for identifying causes is “why ?”. Keep asking the question till the root causes are identified for the immediate, secondary and tertiary causes.
5. Explore the relationship between all the causes and connect the rectangles as in step-3. Show as many relations among different causes as possible. A large number of routes leading to the same root causes provides an indication that the root cause may be an important contributor to the problem.
6. Brainstorm to find the more important root causes and more prominent links leading to the effect. Mark these by making the rectangles and the connecting lines darker.
7. If necessary, rearrange the rectangles in such a way that the connecting lines are short and the diagram compact.
8. Provide a suitable title to the diagram.

Applications

Relations diagram can be applied to explore cause and effect relationships, especially in complex situations where the causes are likely to be mutually related. The most common use is in problem solving to identify multiple interrelated causes. The output of the tool is a list of root causes for the problem with some indication of their relative importance. The output has to be considered as only an indication of the relative importance of the causes. Data has to be collected to confirm or reject the conclusions arrived at the end of the session. Priority of corrective actions to eliminate the causes should be based on the data collected, not on output of relations diagram. The output of relations diagram is based on the perception of the members of the group brainstorming the issue; it needs to be supported by facts. While the output is important as it points a direction to data collection efforts, it is no substitute for facts and data.