when simple charts are surprisingly confusing

Here's a tip we share frequently: keep your charts as simple as you can. Limit the amount of information you display at any one time, use graph types people know, and explain with clear, precise words what the visual is showing. These steps go a long way towards making your message easy for anyone to understand.

With that in mind, it's hard to believe that a simple bar chart with a single series of data could ever be considered to be confusing. But making a chart truly simple starts way before you make any design or graphing decisions. 

Recently, I was working with a company that helps small local businesses understand their sales and consumer data. One of their clients, a coffee house called Mellow Bean, receives regular updates and analyses on both their own sales and their competitors’ sales.

As part of my collaboration with them, the company shared a graph with me from Mellow Bean’s monthly report. Before going into details, let’s look at the chart. If a picture is worth a thousand words, it should speak for itself, right?

Looking at the chart, you might think, “For such a simple chart, why am I so confused?” It's a bar chart with one data series, a title, a subtitle, and more info at the bottom. But the real challenge isn't the design, layout, or labeling. It's the assumptions made before creating the chart. For example, the chart uses the acronym "ADS" without explaining it. Does everyone know it means Average Daily Sales? And does “Gap Analysis” make sense to coffee shop owners?

Let’s take a two-stage approach to strengthen this graph. First, without changing the underlying visual much, if at all, we can use words to make the key messages easier to understand. Second, assuming we have the time, inclination, and authority to modify the graph itself, we can iterate to a visual that more neatly dovetails with the newly-added text.

FIRST STAGE: improve the text 

The average viewer seeing this visual will have to do a bit of detective work to fully understand it. They’ll have to look at the text above and below the chart, guess what "ADS" means, and figure out why the dollar amounts in the graph are so small. (It’s probably because they're averages, not totals; my condolences to the coffee shop with $20 in monthly sales!)

Now let’s clarify things. I’ll restructure the text surrounding the graph, by both highlighting the main takeaway at the top and labeling the bars more clearly.

We’ve now made it easier for viewers to understand what's happening, but there is still more we can do. Adding some context, like the fact that September sales went up due to students returning to the university campus, will give a fuller picture. Mentioning the exact ADS for Mellow Bean, and how big the gap is between top competitors, also helps.

We can improve further by suggesting what to do with this information. What action should Mellow Bean take based on this data? Let’s add that in as well.

SECOND STAGE: improve the visual

Once we've cleared up the message with words, we can think about how to visualize it better. Instead of just showing gaps, why not display the actual Average Daily Sales for each competitor? This gives a clearer sense of the revenue differences between the coffee shops.

What’s easier to see, once we’ve switched to this new bar graph?

• Pore Over, the obvious outlier, is in a class by itself.

• Mellow Bean is close to, but trailing, two competitors with similar sales levels. 

• Below Mellow Bean, the next two cafés are about $150–$175 behind on daily sales.  

Even though all of this information was explicitly visualized in the original graph, it doesn't feel intuitive the way that it does when experienced in this more commonly seen layout.

We could go a step further and include these explicit gaps as well, simply by adding a smaller bar graph to our new design:

Let’s quickly compare where we started and where we are now:

With these changes, the chart becomes more accessible and easier to understand for everyone. Even though both graphs use text to add context for the viewer, the graph on the right uses full sentences, complete thoughts, and more intentional labeling, color, and position of that text, all of which leads a viewer to a more robust understanding of the scenario and an idea of what to do with that information going forward.

Keeping things simple isn't just about choosing common charts, adding a few words of context and minimizing the amount of data you show. It’s essential to take a beat, consider the audience’s perspective, and imagine how they’ll feel when they first see the communication you’re planning. If you skip this thoughtful consideration up front, your audience may well discover that even a simple chart can end up being surprisingly confusing.