Relation diagrams show connections between items such as areas, factors, issues or processes. Connecting lines between the shapes indicate the relationship. Arrows are often used to represent how one item has an effect on another (see example below).

Relation diagrams help to show cause-and-effect relationships. They are best used when trying to analyse and communicate links between things.

Types of relation diagrams include comparison diagrams, conceptual diagrams, fishbone diagrams, cycle diagrams and cladograms.