What’s your chart’s purpose?

In the last installment in this series, we looked at how knowing your audience can influence your chart design. Here, we’ll dig deeper into the chart as a method of communication, and how your own goals affect the best choice.

Once you understand the audience and broader context for a visualization, it is time to dig deeper into the purpose of the visualization itself. What goals is it helping you to achieve? What are you trying to communicate? What tasks does your user need to accomplish by using this graph?

What are your core objectives?

A visualization can serve many purposes. I like to break these down into three core objectives, each of which influences your design choices in different ways. (You can find more detail on this in my master’s thesis. I have since discovered that Andy Kirk has a similar breakdown in his book Data Visualization as well.)

Explore: Allow a user to navigate through the data

• Support an expert in understanding patterns and making advanced queries
• Help someone to see connections and relationships
• Represent a complicated system or information space

Explain: Present an argument, convince, or inform

• Build a data narrative to support decision making
• Teach someone to understand an interesting topic
• Document what happened, using visualization to emphasize important points
• Report the results of your analysis and recommend a particular interpretation or course of action
  
  

Excite: Create stronger engagement with a topic or inspire an emotional response

• Help people to see why your topic is important, or convince people to support your cause
• Represent an experience, a value system, or an identity that connects with viewers
• Show the impacts of something that is usually hidden or invisible
• Build a vision for what could be
• Demonstrate the scale or extent of a problem, or the potential impact of a solution

A single visualization can incorporate many of these objectives, or focus on only one. A visualization can help users to explore the effects of climate change and understand its causes, while also inspiring them to take action and create change. A beautiful visualization that makes a powerful emotional appeal is likely to fall flat at a scientific conference, where the norms dictate that visualization is used to explain a conclusion based on the data and that all subjective considerations should be put aside. That’s not to say that scientific visualizations cannot be exciting or have an emotional impact, but they usually go about it in a different way. Similarly, a scientific graphic will not be accessible to most readers of a newspaper article, without some kind of introduction or explanation. Knowing your core objectives sets the context for all other decisions in your design, and creates the standard against which your piece should be judged.

Desired outcomes

In addition to understanding what your user needs to experience, it is also important to consider what you hope to achieve. An internet user might just want a snappy visualization to share on social media, but you probably also have a point that you’re trying to convey. Before starting your visualization, it’s worth asking yourself what outcomes you are trying to create.

• A viewer learns something
• The right decision gets made
• Someone understands a topic in a new way
• Users feel a sense of connection or an emotional response to a piece
• People are inspired to take action
• Viewers see themselves reflected in the data in a new light
• The piece goes viral on social media

In the next installment of this series, we’ll see how these considerations apply to design choices and chart recommendations for the dashboard vis that we started re-designing in the last article.