Callout numbers are one of the easiest ways to communicate what is most important to you in your data-driven story. A Google Images search for “callout” provides several examples of speech bubbles, thought bubbles, and Batman-style “BAM” / “POW” graphics. While I typically do not enclose my callout numbers in such an illustration, they share the purpose of explicitly telling the main story in your data visualization.
Callout numbers, as I’m calling them, are simply oversized numbers that should be in a legible font that is easy to consume. As these callout numbers will be communicating the most important numbers in your view, they should be prioritized near the top and left of your dashboard. For more on prioritizing and laying out content, see tip five, Use the Golden Ratio.
In tip four, we discussed keeping your data visualizations simple. I also shared a general rule of thumb to keep the widgets on your dashboards to twelve or less. This is a critical concept if you want to cut through the noise and be as effective as possible at communicating the story in your data. Callout numbers provide a means for cutting through the noise, even within your own views.
Here is an example from my portfolio using callout numbers. This viz includes two numbers that stand out: (42) Jackie Robinson’s number that is retired league-wide and (71) the number of seasons without integration in MLB. The end user can see instantly what the dashboard is about and why I think the content is important. From there, they can decide whether or not they want to explore the data.
If you use callout numbers in your view, they will likely be the first thing that your end users are drawn to. This serves two important purposes: (1) it instantly tells the main point of your dashboard and (2) gives the end user a natural place to decide whether or not they need to continue searching for the answers or context they are looking for. This could come into play with C-level executives, who may only want a top-level data point before leaving your visualization – and this is not necessarily bad.
I compare this behavior to a website’s bounce rate. There is a common misconception that it is always bad to have a high bounce rate (or rate of people that view only one page on your website before leaving). However, a perfectly optimized webpage that provides exactly what the visitor is looking for without making them search for it on a second page will have a very high bounce rate. In the corporate world, you may have numbers that do not fluctuate very often, and callout numbers will be a valuable tool for either providing what users are looking for or communicating that it’s important for them to investigate further.