In a concept map, a shape of some sort may enclose some or all nodes. In this aspect, it is similar to a flow chart. Again, this is consistent with the outlining structure that underlies concept maps. Arrowheads are not used. Such diagrams are often used for individual brainstorming and can be used in group brainstorming sessions as well.
Influence diagrams follow the digraph convention by linking blobs or boxes.
Like a systems map, it is a snapshot . It represents the main structural features of a situation and the important relationships that exist among them. This diagram is useful not only for understanding relationships but also as a precursor to restructuring them. Arrows show that influence can or does flow in the direction indicated. Use double-headed arrows only to show mutual, reciprocal influence of the same type, quality, and degree.