Better Living Through Graphs, Part 2

More Learnings from my just-completed Data and Text Visualization course at Northwestern

My five best practices for visualizations:

1. Know what your message is, and whom the audience is / audiences are. The rest of the best practices only matter if the message and audience are clearly defined.
2. Use the visualization(s) that best conveys that message. Here is where to use William Cleveland and Robert McGill’s hierarchy of elementary perceptual tasks as recommended by Alberto Cairo in The Truthful Art. And then use this visualization as part of a story, as Bill Shander explains in his Data Visualization: Storytelling video series. 
3. Simplicity is the best policy. Reduce clutter, both graphical and textual. 
4. Think about how you are guiding the user’s eye through your visualization, i.e. how are you using contrast, motion, and (visual) noise? (The thesis of Moving the Eye Through 2-D Design: A Visual Primer by Buy Shaver, one of my design instructors at the University of the Arts.)
5. Use good graphic design principles. This includes selecting only as many colors as necessary to convey your message, being judicious with your typography, etc. This also includes being as inclusive as possible with your color choices, e.g. being mindful of color vision deficiency, etc.

My five best practices for user-input components of interactive visualizations:

1. Strive for maximum usability. Example: Make the things that are clickable easy to click. Small click target sizes for cursors or fingertips can be frustrating and can negatively impact user experience.
2. Strive for maximum accessibility. As Steve Krug says in Don't Make Me Think, “Making things more accessible benefits everyone.”
3. Strike a good balance between Krug’s First Law of Usability (“Don’t Make Me Think”) and Cairo’s recommendation in The Truthful Art to explain “how your visualization works” or provide an annotation layer. Often, you can find this balance by...
4. ...testing your interactive visualization with as many people, browsers and devices as possible. People are good at finding pain points for you to fix! (Although intended for websites, Krug’s second book Rocket Surgery Made Easy is a great resource for doing quick usability testing of any kind.)
5. Give users as much control (through clicking, dragging, sorting, etc.) over the data they are being shown. This will lead to a more positive experience for the user.

Writing these best practices was part of a class assignment – I would have written more but five was the limit. What are your best practices for visualizations?