A surprising amount of visualization design and analysis can be wrapped up in the single question “What does this visualization make easy to see?”
After teaching visualization for many years, I finally realized that there is this single core question at the heart of visualization. I think we can use it to shape a lot of what we do in terms of visualization practice:
What design choices should we make in order to make the things we want to see easy to see?
The power of a visual representation is that it can make certain “things” easy to “see.” The scare quotes are intentional because those are a bit handwavy - I’ll come back to them. The idea of “something we make intentionally easier to see” gets at the notion of task (why are we making a visualization). See 1 - What Is Visualization and How do We Do It? to get at that core question of task.
What’s amazing about this question:
- It gets at the core of visualization design. We seek to make pictures that make make it easy to see the things that the viewer needs to see. (or, my prefered way to talk about visualization, achieve the task). We can consider design decisions in terms of how they will make certain things easier (or less easy to see).
- It provides a concrete way to critique and compare visualizations. We can ask the question literally - “what does this visualization make easy to see?” We can use it to motivate follow ons like “how does this visualization make it easy to see (the things it makes easy to see)”.
The double edge of this sword is important: if a visualization makes something easy to see, there is almost certainly something else that it is making less easy to see.
The core of visualization design is making a hard decision: what am I going to make easy to see (at the potential expense of everything else). This is why task is so important: it lets us know what needs to be easy to see so we can work to make it easy to see.
If we know the task, then we also know the “non-task” (the things we are not as concerned that the visualization does well). We can make choices (design) so that the visualization is good for the task, The more clarity and specificity we have about the task, the more able we are to know that “everything else” is the “non-task”
If you’re doing critique (even self-critique): ask “what does this visualization make easy to see” (and also “what doesn’t think visualization)