DV

Five qualities of great (persuasive) visualizations

1. Truthful. Based on thorough and honest research.
2. Functional. Constitutes an accurate depiction of the data, and built in a way that lets people do meaningful operations based on it (seeing change in time).
3. Beautiful. In the sense of being attractive, intriguing, and even aesthetically pleasing for its intended audience—scientists, in the first place, but the general public, too.
4. Insightful. Reveals evidence that we would have a hard time seeing otherwise.
5. Enlightening. If we grasp and accept the evidence it depicts, it should change our minds for the better.

B.E.F.I.T. qualities, in short.

An example of a visualization that has the BEFIT qualities is the Hockey Stick Chart.

Earth has warmed in the past century, that it continues doing so at an alarming pace, and that humans have a key role in that warming isn’t controversial today. Disagreements exist on the details, as is normal in science, and a lot of research remains to be done, but most of the scientific community agrees that climate change is a worrisome reality.

The graphic shows temperature variation measured in degrees Celsius in comparison to the 1981 to 1990 average, the zero line in the middle of the Y-axis.

No statistical estimate is fully accurate, so the authors were careful to display uncertainty in their chart: notice the gray strip that surrounds the lines. With a very high degree of confidence, scientists can claim that the temperature of each year was within the range defined by the uppermost and the bottom tips of that gray strip.

The message of the chart is unambiguous: in the first years of the twentieth century, temperatures experienced a sharp rise. This was a time when emissions of human-made greenhouse gases, like carbon dioxide from fossil fuels, increased rapidly.

The hockey stick chart is one of the most iconic and persuasive visualizations ever created.

Truthful

“Get used to not just seeing or looking at visualizations but to reading them.”

Example 1

Do you see anything fishy in the following chart?

Example 2

The chart below shows the production cost of two products. They clearly co-vary, don’t they?

The data look quite different, if we plot the lines on the same scale.

Clarity can be a trap!

A graphic that is clear may or may not necessarity be truthful. Clarity need not be the primary goal of visualization design.

Being truthful involves two different but tightly connected strategies:

• Avoid self-deception. We humans evolved to see patterns in meaningless noise. We jump to conclusions. We see causality where there’s only correlation. Truthful graphics are created by people who do their best to prevail over their intellectual shortcomings and cognitive and ideological biases by applying certain critical thinking techniques.
• Be honest with your audience. Show them your best understanding of what the reality is. We should strive to pursue and deliver “the best obtainable version of the truth.”

Functional

A visualization should help the audience interpret it correctly.

Which of the two visualizations below is more functional (slope chart on the left vs two pie charts on the right)?

The purpose of your graphics should somehow guide your decision of how to shape the information.

Beautiful

What matters isn’t if the objects of our creation are beautiful or not per se, but if they are experienced as beautiful by as many people as possible.

Beauty is, thus, not a thing, or a property of objects, but a measure of the emotional experience of awe, wonder, pleasure, or mere surprise that those objects may unleash. Beauty matters because attractive and pleasing things work better. They put us in good mood, and so they invite us to invest some effort in understanding how to operate them.

Which chart is more aesthetically pleasing?

Insightful

The purpose of visualization is insight, not pictures. Visualizations that offer just obvious and trivial messages are worthless. Implicitly, their designers ask you to invest effort in reading them in exchange for very little return.

Two kinds of insight: spontaneous insight (‘eureka’/’a-ha’ moments) and knowledge-building (gradual and deliberate process of exploration) insight. The knowledge-building insight is much more common in interactive visualization.

Here is an example. Women tend to choose graduate programs in the social sciences and the humanities more than men do but there is a huge gender imbalance in science and engineering.

Enlightening

Ultimately, the goal of any candid visual communicator is to give people access to the information they need to increase their well-being. Great visualizations change people’s minds for the better. They are enlightening.

The topic of the visualization is also important. Choosing topics ethically and wisely—casting light over relevant issues—matters a lot. Some topics do matter more than others indeed because they are more critical to the well-being of more people.

Here is an example. Esteve (a student of A. Cairo) turned in a project that explores every episode of the first season of “Buffy the Vampire Slayer”. You can see which characters were onscreen in each scene and sort and filter the data in different ways. Esteve didn’t work with an existing database, by the way. He watched all episodes repeatedly to time each character’s appearances.