How to Master Data Visualization

A few rules of thumb for designing with charts and graphs

Illustrations courtesy of the author

You’ve got a credible statistic or two, and you’re ready to share that information with your audience. Do you write it out? Draw a picture? Use a chart? To make sure your audience understands and retains the information, it needs to be compelling and accurate.

But the choice of what type of visualization to use isn’t purely aesthetic, nor is it entirely personal. The wrong choice can lead your viewer to boredom, confusion, or both. Even worse, visualizing data inaccurately can constitute a breach of trust between you and your audience.

So let’s take a look at how to choose the most accurate and engaging way to visualize your data.

Bar graphs

For data sets that evolve over time or are grouped by multiple categories—like different industries or foods—or both, a bar graph is a solid choice. A few tips will help ensure your bar graph is easy to read:

• Order your bars chronologically.
• Use one axis to label the time frames, and use the other to label the quantities.
• Never order the data from most to least or least to most—chronology is the better measurement for your viewer.

For bar graphs that involve multiple categories, you can either make individual graphs for every category or keep it as one by including multiple bars (one for each category) at each time label. These bars can be side-by-side or stacked on top of each other, as in this graph from an interactive annual report for Bluetooth:

Bluetooth-enabled device shipments worldwide (billions). Excerpt from an interactive report for Bluetooth, designed by Killer Visual Strategies.

If your data set is grouped into multiple categories and is NOT bound by time, you should organize the bars from most to least, or least to most. This type of organization helps viewers to draw conclusions quickly. However, if it adds up to a whole—such as total revenue by category—that won’t be apparent in a bar graph. For…