Storytelling with Data: A Data Visualization Guide for Business Professionals

by Cole Nussbaumer Knaflic

Concentrate on the pearls, the information your audience needs to know.

First, To whom are you communicating? It is important to have a good understanding of who your audience is and how they perceive you. This can help you to identify common ground that will help you ensure they hear your message. Second, What do you want your audience to know or do?

You should always want your audience to know or do something.

Often, this discomfort seems to be driven by the belief that the audience knows better than the presenter and therefore should choose whether and how to act on the information presented. This assumption is false. If you are the one analyzing and communicating the data, you likely know it best—you are a subject matter expert. This puts you in a unique position to interpret the data and help lead people to understanding and action.

While it sounds easy, being concise is often more challenging than being verbose.

Mathematician and philosopher Blaise Pascal recognized this in his native French, with a statement that translates roughly to “I would have written a shorter letter, but I did not have the time” (a sentiment often attributed to Mark Twain).

The fact that you have some numbers does not mean that you need a graph!

If you need to communicate multiple different units of measure, this is also typically easier with a table than a graph.

Using a table in a live presentation is rarely a good idea. As your audience reads it, you lose their ears and attention to make your point verbally. When you find yourself using a table in a presentation or report, ask yourself: what is the point you are trying to make? Odds are that there will be a better way to pull out and visualize the piece or pieces of interest. In the event that you feel you’re losing too much by doing this, consider whether including the full table in the appendix and a link or reference to it will meet your audience’s needs.

Don’t let heavy borders or shading compete for attention. Instead, think of using light borders or simply white space to set apart elements of the table.

For more on table design, check out Stephen Few’s book, Show Me the Numbers. There is an entire chapter dedicated to the design of tables, with discussion on the structural components of tables and best practices in table design.

While tables interact with our verbal system, graphs interact with our visual system, which is faster at processing information.

Slopegraphs can be useful when you have two time periods or points of comparison and want to quickly show relative increases and decreases or differences across various categories between the two data points.

Sometimes bar charts are avoided because they are common. This is a mistake. Rather, bar charts should be leveraged because they are common, as this means less of a learning curve for your audience. Instead of using their brain power to try to understand how to read the graph, your audience spends it figuring out what information to take away from the visual.

The rule we’ve illustrated here is that bar charts must have a zero baseline.

Note that as you add more series of data, it becomes more difficult to focus on one at a time and pull out insight, so use multiple series bar charts with caution.

If I had to pick a single go-to graph for categorical data, it would be the horizontal bar chart, which flips the vertical version on its side.

We’ve discussed the visuals that I use most commonly to communicate data in a business setting. There are also some specific graph types and elements that you should avoid: pie charts, donut charts, 3D, and secondary y-axes. Let’s discuss each of these.

One of the golden rules of data visualization goes like this: never use 3D. Repeat after me: never use 3D.

I tend to avoid center-aligned text for this reason.

Perhaps you’ve heard this feedback before: “there is still some space left on that page, so let’s add something there,” or worse, “there is still some space left on that page, so let’s add more data.” No! Never add data just for the sake of adding data—only add data with a thoughtful and specific purpose in mind!

If there is one thing that is really important, think about making that the only thing on the page. In some cases, this could be a single sentence or even a single number.

Studies have shown that we have about 3–8 seconds with our audience, during which time they decide whether to continue to look at what we’ve put in front of them or direct their attention to something else.

Roughly 8% of men (including my husband and a former boss) and half a percent of women are colorblind. This most frequently manifests itself as difficulty in distinguishing between shades of red and shades of green. In general, you should avoid using shades of red and shades of green together.

There are a number of sites and applications with colorblindness simulators that allow you to see what your visual looks like through colorblind eyes. For example, Vischeck (vischeck.com) allows you to upload images or download the tool to use on your own computer. Color Oracle (colororacle.org) offers a free download for Windows, Linux, or Mac that applies a full-screen color filter independent of the software in use. CheckMyColours (checkmycolours.com) is a tool for checking foreground and background colors and determining if they provide sufficient contrast when viewed by someone having color-sight deficiency.

When it comes to the form and function of our data visualizations, we first want to think about what it is we want our audience to be able to do with the data (function) and then create a visualization (form) that will allow for this with ease.

When it comes to the perfection of design with data visualization, the decision of what to cut or de-emphasize can be even more important than what to include or highlight.

Use your space and audience’s attention wisely by getting rid of noncritical data or components.

You should be familiar with the detail, but that doesn’t mean your audience needs to be. Consider whether summarizing is appropriate.

Ask yourself: would eliminating this change anything? No? Take it out!

Push necessary, but non-message-impacting items to the background.

The concept of accessibility says that designs should be usable by people of diverse abilities.

Applied to data visualization, I think of it as design that is usable by people of widely varying technical skills.