Mastering Systems Diagrams

Photographers have a catchphrase: “It’s not the camera you have, it’s what you do with it.” (You sometimes hear this variation: “It’s not the camera, it’s the photographer.”) What this means is that the tools you use are less important to outcomes than your degree of mastery over the subject. An experienced photographer will make excellent images with a crappy camera, whereas someone who doesn’t know what he or she is doing will mess things up even with top-of-the-line equipment.

Henri Cartier-Bresson—one of the greatest photographers ever—worked with cameras that are primitive compared to today’s tools. Image: Fondation Henri Cartier-Bresson (via Phaidon)

My systems class involves making lots of diagrams. Diagramming software (e.g., OmniGraffle, Visio, and Adobe Illustrator) is often intimidating to students who don’t have design backgrounds. Some assume they must master one of these tools before they can create clear, elegant diagrams. I disagree; the minimum denominator — PowerPoint — will do fine in a pinch.

You don’t need to master “big” software to create great diagrams. Instead, you need:

  • An understanding of who the diagram is for. Are you the audience, or is it someone else? Do they have particular ways of understanding the space that will influence representations?
  • An understanding of the purpose of the diagram. What are you trying to explore or convey? What is the framing question the diagram seeks to answer?
  • An understanding of how to break things down into their constituent elements. What elements should be included/left out of the diagram? Will all elements be represented at similar levels of granularity, or will some be broader than others?
  • An understanding of how to represent relationships between elements. Do some influence others? Are relationships one-way? Two-way? One-to-one? One-to-many? Many-to-many? Are some elements containers for others?
  • Feedback. Are people getting it? Is it clear? What can be improved?

None of these things require software; you can explore them using pen and paper. The more you do it, the better you become at it — and the better you become at it, the better you will be when it comes time to wield the big diagramming tools. Practice is the key; becoming good at it using simple tools will keep you focused on the things that truly matter. Then you can learn the more powerful tools with the confidence that you know what you’re doing.