- Chapter 9 in Alberto Cairo, The Truthful Art1
- Chapter 12 in Claus Wilke, Fundamentals of Data Visualization2
- Kieran Healy, “Two y-axes”
- Two Alternatives to Using a Second Y-Axis & Illusion of success & Dissecting two axes
- Dual-Scaled Axes in Graphs: Are They Ever the Best Solution?3
Questions to reflect on
(Remember, you don’t need to answer all of these—or even any of them! These are just here to help guide your thinking.)
- How can you correctly and honestly communicate relationships between variables? How can you communicate the uncertainty in those relationships?
- What are the dangers of visualizing two variables?
- When is it appropriate to use two y-axes?
The slides for today’s lesson are available online as an HTML file. Use the buttons below to open the slides either as an interactive website or as a static PDF (for printing or storing for later). You can also click in the slides below and navigate through them with your left and right arrow keys.
Fun fact: If you type ? (or shift + /) while going through the slides, you can see a list of special slide-specific commands.
Videos for each section of the lecture are available at this YouTube playlist.
You can also watch the playlist (and skip around to different sections) here:
Alberto Cairo, The Truthful Art: Data, Charts, and Maps for Communication (Berkeley, California: New Riders, 2016). ↩︎
Stephen Few, “Dual-Scaled Axes in Graphs: Are They Ever the Best Solution?” Visual Business Intelligence Newsletter, March 2008, http://www.perceptualedge.com/articles/visual_business_intelligence/dual-scaled_axes.pdf. ↩︎