4 Tips for Creating Clear, Understandable Graphs: Guide for Health Communicators

Prepared by Samuel Mendez

Summary

As health communicators, we know a visual is worth 1000 words. At the same time, we know an informative graph for health professionals might be unusable for many people in our audience. This tipsheet offers advice to elevate your health communication by making graphs and tables more understandable. Start by focusing on 1 main message and 1 call to action. Figure out if you really need a graph to support them. If you do, use these 3 tips:

1. Streamline your graph
2. Include a plain language summary
3. Include alt text
4. Use more than color to convey info

With these tips, you’ll make the complex clear and give your audience insight into their health. Read on to see them in action.

Tip 1: Streamline your graph

It takes lots of practice to read graphs with ease.  For example, reading a bar graph means keeping track of each point along X and Y axes, plus the information from titles and legends. Things get even more complex when the graph uses math concepts like percents or measured units.

So, it’s important to streamline:

• First, cut down your data points as much as you can. For example: maybe you only need to show 1 year of data instead of 5. Maybe you only need to show data from one group, rather than 3.
• Second, streamline your structure. Timelines and pie charts have clearer structures than graphs with X and Y axes. Lists with one heading have clearer structures than tables with row and column headings. Remember: there’s no single figure that works for everyone. Some people prefer text they can copy and paste while others prefer graphs they can screenshot. Some people might find tables helpful while others find them annoying. The format you choose depends on your audience.

To be sure, some messages might require more complex figures. In these cases, ask yourself: are you available for follow-up questions? Can you verify your audience’s understanding? What’s the cost of a misunderstanding? Is your message format the best way to have this complex conversation?

Example of a streamlined graph

Data from the Maine CDC showed fewer deaths in fall 2023 than fall 2022. But the number of deaths was also rising as we headed into the winter.

The timeline below displays the data in a more streamlined format, without X and Y axes. You could make the graph more visually informative by changing the size of each circle to scale with the number of COVID-19 deaths. Or highlight the last few months to discuss the increase in COVID-19 deaths specifically.

The table below is about the same as a timeline. But it is in a more accessible format for devices like screen readers. If the data are important enough to share in your content, then they’re also important enough to share via a data table for better accessibility.

Number of COVID-19 Deaths in Maine (November 2022 to July 2023):

Month	Nov	Dec	Jan	Feb	Mar	Apr	May	June	July
COVID-19 Deaths	64	60	61	55	58	31	19	15	6

The list below displays the data in an even more streamlined format: a list with just one heading.

Number of COVID-19 Deaths in Maine (November 2022 to July 2023):

• 64 deaths in November
• 60 deaths in December
• 61 deaths in January
• 55 deaths in February
• 58 deaths in March
• 31 deaths in April
• 19 deaths in May
• 15 deaths in June
• 6 deaths in July

The line chart in this example is much more informative than the list. By the same token, it also makes more intense health literacy demands. To read it, readers must track data points’ positions along X and Y axes and interpret differences between them. This adds visual processing on top of numbers and months to keep track of. Not everyone can readily perform all these tasks at once. And even fewer people want to. A table or list isn’t as eye-catching or informative, but they are more accessible. For this reason, you will want to share a data table alongside graphs. If the data are important enough to include in a graph, they are important enough to make accessible to people who will read your content through assistive technology.

Learn how to judge the clarity of a table or graph structure

• Use the PMOSE/IKIRSCH to assess the demands a graph or table makes of your audience

Tip 2: Include a plain language summary

As mentioned above, not everyone will read your graph or table. A picture might take too long to load on free wi-fi. A graph might be too complex. A table might be more trouble than it’s worth on a screen reader. So, make sure someone doesn’t need to both see and correctly read your figure to get your main message.

Include a summary of graphs and tables. On a content system like WordPress, this might involve a formal “caption” or “figcaption” tag in HTML. On video platforms, this might involve a verbal summary with a text copy in the description. No matter the format, make sure this summary can stand on its own. This means no jargon. This also means focusing on key takeaways. Including a text summary will have the added benefit of helping your content show up in search engines.

Example of a figure summary

Let’s look at our timeline above. If we were to include it on a slideshow on social media, we would want to describe it in the space we have for captions. Here is an example caption:

Slide #1 shows a timeline of COVID-19 deaths from November 2022 through October 2023. The number of deaths was at a high of 63 in November. Deaths were at a low of 6 in July. But they rose back to 30 in October. This is a sign that we still need to take steps to reduce the spread of COVID-19.

If you have the option, try to add a formal figure caption HTML element so its purpose is clear. You probably won’t be able to do this on social media, but you should be able to on your own website.

Learn how to create graph captions

• Learn to describe graphs from Harvard University’s IT department
• Learn more about figcaption HTML elements from MDN Web Docs
• Learn how to add captions in a typical WordPress editor

Tip 3: Include alt text for graphs

Like all images, you should add alt text to your graphs for better accessibility and search engine optimization. These should work in tandem with any plain language summaries you include.  If you follow the tip above, the graph’s key info should already be available in text. So, the alt text should be short. It should identify the image and describe its key features, making its purpose clear.

Example alt text

Our alt text for the figures on this page are examples of this tip in action. The alt text for the line chart reads

Graph titled “COVID-19 Deaths in Maine: November 2022 through October 2023.”

The alt text for the timeline reads:

Timeline titled “Monthly COVID-19 Deaths in Maine: November 2022 through October 2023.”

Our figure captions include enough info to interpret the graphs and perceive the key takeaways even if you don’t look at the images. So, our alt text serves more of a signposting role. It lets people using screen readers know where an image is and the kind of info it conveys. The rest of our content works with the alt text to keep it concise.

Learn how to write effective alt text for graphs

• Learn how to write alternative text for visuals from Johns Hopkins
• Learn how to write chart & diagram alt text from University of South Carolina
• Learn how to add alt text on popular platforms:
  • Add alt text on Squarespace
  • Add alt text on Instagram
  • Add alt text on Facebook

Tip 4: Use more than just color to convey information

Not everyone sees colors the same way you do. And not everyone’s screens are calibrated the same. So, we must design our graphs so people can get the important info without having to see the colors. To do so, we convey important info using shapes, patterns, and labels as well. In a bar graph, this might mean using patterns and outlines to differentiate groups from each other. In a line graph, this might mean using different shapes to illustrate data points from different groups. In a pie chart, this might mean labeling the chart directly rather than relying on a legend.

Example graph using patterns, labels, and colors to convey info

Let’s use a hypothetical example to illustrate these strategies in action. Let’s say we had an orchard and we made the pie chart below to show our distribution of red, green, and yellow apples.

This chart is inaccessible to anyone who can’t tell the difference between the red, green yellow, and white colors we used. Thus people with colorblindness, dim screen settings, or blue light filters might not be able to read it, even if they are used to reading graphs. Here are the major issues with this graph:

• The pie chart slices are differentiated only by color.
• The legend requires users to differentiate each box by color alone, then connect each box to each slice by color alone.
• The colors are low contrast with the white background

The graph below fixes the major accessibility issues by using color, patterns, outlines, and labels to convey important info.

Learn more about accessible color contrast

• Use WebAIM’s color contrast checker to ensure you use colors with high contrast between your graph elements and their backgrounds.

Conclusion

This tipsheet offered advice on making clear, accessible graphs. It provided guidance for:

• Focusing on one main message and one call to action
• Making sure your graphs support your main message and call to action.
• Streamlining your graph and trying out different formats to avoid information overload.
• Adding a plain language summary and alt text for better accessibility and search engine optimization.

This tipsheet is part of a series on clear communication. It bridges knowledge from health literacy, web accessibility, and journalism to help you elevate your health communication. Combine your accessible graphs with clearer writing for even more impact.

This tipsheet was prepared by Samuel R. Mendez. It was reviewed by Amanda Yarnell and Elissa Scherer.