Legal blindness, vision impairment, and color vision impairment are very common issues:
- "...findings from the 2015 National Health Interview Survey (NHIS) data release established that an estimated 23.7 million adult Americans (or 10% of all adult Americans) reported they either "have trouble" seeing, even when wearing glasses or contact lenses, or that they are blind or unable to see at all.”
- Color vision impairments affect ~5% of individuals. Rates vary based on population groups and ethnicity, but in the United States, red-green color vision defects are the most common, followed by blue-yellow defects and blue cone monochromacy.
There are several common-sense steps you can take to make your visualizations more accessible to a wider audience, including folks with a variety of visual impairments.
The Web Concent Accessibility Guidelines (WCAG) were created by the World Wide Web Consortium (W3C) to develop standards & ratings to ensure inclusive design on the web.
These guidelines mandate that materials are:
Here, we will focus on changes you can make to make your visualizations more perceivable and understandable to diverse users.
Color blind palettes or the ability to create a custom palette is available for most visualization tools.
Choosing color blind palettes in Excel
Choosing color blind palettes in Tableau
Perceivable: Alternative Text
Adding alt text to charts provides the flexibility for users to change the content into other forms, like large print or speech.
Adding Alt Text to visualizations in Excel
Understandable: Legible and Clear
Create separate, distinctive visualizations are easier for everyone to read and doesn’t distort content for viewers who are using a screen reader.
Ensure your content appears in a logical order, that filters and navigation tools are consistent, and that views only changes when the user initiates it.
Based on a webinar given by Kelsey McCormick and myself in Winter 2018: "Visually Accessible Design & Data Visualization 101"