WASHINGTON, D.C. – The way Albert Cairo describes it, data visualization can be a tool as simple yet powerful as a hammer or even a superpower, like X-ray vision.

“Visualization is going mainstream,” said Cairo, the Knight Chair in visual journalism at the School of Communication of the University of Miami, during Friday’s keynote at the Nonprofit Technology Conference. More than 2,300 attendees are at the annual conference, sponsored by the Nonprofit Technology Network’s (NTEN), at the Marriott Wardman Park.

Cairo, also director of the visualization program of the Center for Computational Science and author of the book “The Functional Art: An Introduction to Information Graphics and Visualization,” presented “Data visualization: Effective communication with maps, charts, and graphs.”

“It’s extremely persuasive,” Cairo said of data visualization. One reason why visualization is becoming mainstream is that it’s effective at communicating information but also can be extremely persuasive. A visualization is a representation designed to enable exploration, analysis, or communication.

New and traditional journalism outlets are doing data visualization because the analytics show that the public really likes those graphics and reads visualizations. The most effective visualizations are those that once “you see it you can’t unsee it,” Cairo said. “There’s a clear before and after pattern,” he said, sharing visualizations about data from the Intergovernmental Panel on Climate Change that showed departures in temperature from 1961 and 1990.

Another example came from The Wall Street Journal, with a graphic featuring a heat map about measles and historical vaccinations by state since 1930 titled “Battling Infectious Diseases in the 20th Century: The Impact of Vaccines.” The graphic clearly demonstrated a rapid decline in cases of measles since the introduction of the vaccine in the 1960s, to the point that it was almost non-existent by 1980.

Nonprofits and think tanks are producing very informative infographics and visualizations, Cairo said, pointing to such organizations as the Pew Research Center in Washington, D.C. Cairo offered four core principles of visualization for communication. Good graphics should:

• Be based on good data;
• Attract readers’ attention;
• Don’t frustrate readers; and,
• Show the right amount of data.

He also suggested three foundational text books on data visualization: “Exploratory data analysis,” “Understanding data,” and “Introduction to the practice of statistics.”

Good data visualization will not simplify information but clarify the information, Cairo said. Sometimes you have to increase the amount of information you present as you seek the sweet spot of a graphic that’s truthful and appealing, he said.

Whenever someone hides important data in a graphic, it usually means they’re trying to hide something. He provided some examples of simplification that obscures, not illuminates, the data. One included truncated data about infrastructure investment by cable companies as it relates to industry deregulation in the 1990s.

A hammer extends your arm and makes you stronger. It’s the same thing with visualization. Likewise, consider the purpose of visualization: It’s not just pretty pictures but pretty pictures that are useful. If visualization forces you to read all the numbers, it has failed, Cairo said. A pie chart is not a good way to represent change since it’s intended to show parts of a whole. Instead, to show change over time, it’s better to use a line graph.

Making it clear is not enough, make it interesting. And don’t just make it clear, make it engaging. “Think of the tasks your graphic is supposed to enable or the questions it’s supposed to help people answer.”