Pretty circular things
Five steps to let the young ones shine

Is the visual serving the question?

The following chart concerns California's bullet train project.


Now, look at the bubble chart at the bottom. Here it is - with all the data except the first number removed:


It is impossible to know how fast the four other train systems run after I removed the numbers. The only way a reader can comprehend this chart is to read the data inside the bubbles. This chart fails the "self-sufficiency test". The self-sufficiency test asks how much work the visual elements on the chart are doing to communicate the data; in this case, the bubbles do nothing at all.

Another problem: this chart buries its lede. The message is in the caption: how California's bullet train rates against other fast train systems. California's train speed of 220 mph is only mentioned in the text but not found in the visual.

Here is a chart that draws attention to the key message:


In a Trifecta checkup, we improved this chart by bringing the visual in sync with the central question of the chart.


Feed You can follow this conversation by subscribing to the comment feed for this post.

The comments to this entry are closed.