A few days ago I received an email from Thomas Watkins, who is an avid reader of this blog and a past participant in one of my Visual Business Intelligence Workshops. He asked my opinion of this infographic, which recently appeared in the New York Times.
It looks a bit like a solar system with really strange orbits. Displayed as a node-link diagram, the information seems quite complex—much more so than necessary. Rather than responding to Thomas with my opinion, I asked for his. As a highly-motivated student of data visualization, Thomas volunteered to provide more than I asked: “I started to write my thoughts, and I figured it would be better if I tried to actually attempt a redesign.” Three days later, he emailed me the following:
In the original graph by Bill Marsh of The New York Times, the first thing that jumps out at me is that it’s difficult to understand what’s even going on. I think The New York Times editing staff realized this, because they offer a fairly lengthy breakdown demystifying the visualization. This graph suffers from the classic problem of encoding quantitative values as area instead of length or 2D location. Trying to figure out which countries owe debt to other countries and the amount owed requires the reader to carefully trace arrows from one bubble to another. The graph also doesn’t even attempt to visually encode the very important metric of ‘debt to GDP ratio'; rather, they put the percentage in each bubble. Perhaps there was no more room left to graph it considering the busyness of the current design.
If the purpose of this graph is to convey the feeling of mass confusion that’s associated with the current financial crisis, then maybe it does make sense to use a wild array of bubbles and lines. However, if we want to communicate the broad picture while allowing specific visual comparisons to be made easily, then this visualization could’ve been designed more effectively. Overall I think it succeeds more as a diagram than as a graph.
Thomas then went on to propose the following visualization as a replacement, minus the textual narrative that would be helpful to tell the story completely.
Thomas explains his version of the story as follows:
In my redesign I used horizontal bar graphs to rank each country by the size of their economy. Next I made a column for the ‘debt to GDP’ ratio. I figured that the two most important messages regarding this metric were (1) how high the ratio is, and (2) the ratio’s deviation from 100%. Therefore I made it a bar graph with a reference region. For the 3rd column I nested a set of ranked horizontal bar graphs within each country’s row. Finally, I plotted a simple dot next to each of the “worrisome” countries to indicate the ‘color of trouble’ from the original graph. My color of trouble varied on color intensity rather than hue to promote continuous rather than categorical perception.
I found Thomas’ version far superior to the original. What’s more, using Thomas’ design, additional metrics could be added to the display to enrich the story without overcomplicating it. Perhaps my friends at the New York Times should hire Thomas as an adviser.
(Author’s note, upon further reflection: I realize now on Sunday, November 13th that I should have chosen my words more carefully in my original blog post when I described Thomas’ visualization as a “replacement” for the original network diagram that appeared in the New York Times. It is not a replacement in the sense that it intends to do what the original intended, but in the sense that it attempted to provide a more useful and effective visualization of the data; one that displays important information about the indebtedness of Euro zone countries to one another in an accessible way, which complements the story better than the original network diagram. Thomas’ visualization does not attempt to display the complex interconnectedness of debt. He created his own visualization because he found the original network diagram inaccessible and confusing. When he asked for my opinion of the original diagram, I had a similar reaction, which I have to most static node-and-link network visualizations that are designed for journalistic purposes: they look complicated and confusing, and as such do not invite readers to examine the data in useful ways. Network visualizations attempt to provide a synthesis of the many parts and relationships that make up a complex set of interconnections. They are difficult to decipher, in part because the information is itself complex, and in part because our brains cannot process a complex set of visual connections as a whole when displayed as nodes and links. When a network visualization is well designed, we can discern a few useful attributes regarding the whole—mostly outliers and a few predominant patterns. Beyond this, we must break the information down into parts and focus on them one at a time, which almost always requires the ability to interact with the visualization, such as by filtering out what’s not needed or by highlighting objects of focus in the context of the whole. I did not object to the original diagram that appeared in the New York Times because I felt that it was poorly designed, but because, in static form, it was not an effective use of static graphics to complement the story for its readers.)