If you are trying to reach a large audience with your charts, maps, and graphs, then consider accessibility issues. Even if your data viz is meant for a small, specific audience, you may not be aware that certain people in the group are, for example, color blind or have other issues that affect their ability to see or interact with a visualization.
If you are interested in a deep dive into accessibility issues and solutions, you can find plenty of information online including Chartability. In a series of 60-second data tips, I’m taking on one basic accessibility issue at at time. This week it’s contrast.
Data visualizations must be perceivable to be accessible. This means that users can readily identify content using their senses: sight, sound, and touch. When the contrast between the critical content and the background or adjacent colors is low, the content can be difficult to perceive for some people. So shapes and large text should have more than a 3:1 contrast against background or adjacent content, and regular text should have more than a 4.5:1 contrast. Here’s a tool to determine contrast ratio.
The colors in the first stacked bar chart below have low contrast to each other (less than 2 to 1) and so some may have difficulty distinguishing among the bar segments. The second stacked bar chart, by contrast (pun intended), has a higher ratio (3 to 1) and thus is much easier to perceive.
To see past data tips, click HERE.
Let’s talk about YOUR data!
Got the feeling that you and your colleagues would use your data more effectively if you could see it better? Data Viz for Nonprofits (DVN) can help you get the ball rolling with an interactive data dashboard and beautiful charts, maps, and graphs for your next presentation, report, proposal, or webpage. Through a short-term consultation, we can help you to clarify the questions you want to answer and goals you want to track. DVN then visualizes your data to address those questions and track those goals.
