I'm analysing the possible outcomes of certain plots in my campaign. At some point I realised that keeping the possible causes and effects in purely text form was inconvenient. Luckily, thanks to an article that I rediscovered thanks to an answer on this very stack, I know the term for the more visual tool that helps handling them: causal influence diagrams.

However, I soon discovered that it's still not always easy to keep all the information visible and distinguishable, without relying on huge notes or keeping all of the relations between elements in mind.

Is there an already developed/established convention of conveying element types and relations in causal diagrams, concisely conveying such information through the graph? If there aren't widespread conventions, does anyone of you have narrower, personal experience of successfully using some way of conveying such information in a diagram for a campaign (largely relating to quests and plots)?

In case it helps answer, here are some of the key things I currently already need to keep track of (but it's likely that I'm overlooking some):

  • Element type is a faction.
  • Element type is a quest item or items (in some cases a unique artefact, in some cases a technological thing of which some number is required and can be developed/produced).
  • Element type is an event.
  • Relation: element (faction) X produces element (item) Z.
  • Relation: element X affects element (usually item) Z.
  • Relation: element X destroys element Z.
  • Relation: element X causes event Z.
  • Relation: element X uses item Y to [any of the above].
  • Relation: only if element X is intact, event Z happens.
  • Relation: only if element X is destroyed, event Z happens.
  • \$\begingroup\$ Are these plot elements influenced by players? If so, I don't think attempting to plot outcome possibilities is possible. \$\endgroup\$
    – NotArch
    Sep 9, 2019 at 14:13
  • \$\begingroup\$ They are. In fact if this graph is meant to be helpful in visualising where are the best key points for targeting by PC influence. If it ends up looking good, maybe such a graph will even become a prop in a session (there are certain ways in which the PCs could either partially or completely divine the most likely directions the timeline may turn). Of course with sufficient influence the graph may break down, but it's nice to have a good aid for visualising for how, where and when the 'normal' courses of events would break down. \$\endgroup\$ Sep 9, 2019 at 14:18
  • 1
    \$\begingroup\$ When you give your players options 1 and 2, what are you going to do when they'll discus between 1, 3, and 5, and end up doing Ź? \$\endgroup\$
    – Mołot
    Sep 9, 2019 at 14:58
  • 2
    \$\begingroup\$ I'm voting to close this question as off-topic because causal influence diagrams, while interesting, are not the focus of this stack. \$\endgroup\$
    – GreySage
    Sep 9, 2019 at 15:16
  • \$\begingroup\$ @Mołot If they find a 'third' option, is not at odds with the purposes of the diagrams. The diagram will help visualise which causal nodes need to be circumvented in order to enable the third option. \$\endgroup\$ Sep 9, 2019 at 15:28

1 Answer 1


Not in the way you suggest

Causal influence diagrams aren't exactly designed for use in RPGs, and I think Neel's original post, while interesting, takes some conceptual liberties with the idea. CIDs are machine learning tools most often used (that I see them, anyway) in a family of problems characterized by or related to Markov Decision Problems. MDPs are far outside the scope of this stack except to note that the types of nodes usually found (utility nodes, chance nodes, etc) don't bear any relevance here.

Even in that context, those different types of nodes are usually denoted by shape, fill color, and sometimes border color or style. Sometimes, arcs from node to node are also decorated, usually with various styles of dashed or dotted lines. I very frequently see legends attached because while those shapes are semi-standard in the field, there are enough special applications and overall variety that legends are always useful and sometimes necessary.

TL;DR - Use shapes and colors, and keep a legend

Unless you are planning on publishing this, you are almost certainly the only person who will ever use or see this tool. You are also the only person who can decide, based on the experience of your own game, what node types are useful. The standard way to distinguish these visually is through shapes and colors, so that is your useful starting point. Within that overall type of scheme, your goal is self-consistency, not compliance with an outside standard. Therefore, what will probably be useful is a self-determined set of shapes and colors, and maintaining a master legend to keep you consistent.

(My experience with these is academic, not gaming. But as an afterthought, I have used something vaguely similar for high level plotting out as arcs. I wouldn't really call it a CID because I wasn't at all thinking about it in that way; it was more of a way to keep track of potential orderings of sub-plots. As I'm thinking about it, I did end up using fill colors to convey information. It wasn't complex enough to need more than that.)


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