Overview
Data visualizations are an increasingly popular way to present complex data sets. They transform raw data into visual formats like charts, graphs, maps, and diagrams, allowing some people to grasp patterns, trends, and relationships at a glance. However, if data visualizations are designed without accessibility in mind, they can present barriers due to their emphasis on visual presentation. Improving features through accessibility features like alt text, sufficient contrast, and simplified design can make your data presentation more accessible to all.
To provide an equitable accessible experience, developers should observe two best practices:
- Apply any accessibility features that are supported by their data management platform
- Create an accessible alternative version of their visualization, including a summary, tabular data, and explanations of trends, sequences, conclusions, or other key elements of the visualization.
Better practices for more accessible data visualizations
Here are some tips to help you create data visualizations that provide value to all users. Note that some tools may not support some or all of these recommendations.
Understand the capabilities of your authoring tool
Different tools provide different levels of support for accessible data visualization. The accessibility of visual data is largely dependent on the expertise of developers and designers to understand capabilities of their chosen platform. Accessibility features such as ALT text for images, well-labeled interactive controls, accessible color palettes, and keyboard operability can provide a more inclusive and accessible experience for some users.
Overview of Accessibility in PowerBI
Visit the Tableau Accessibility FAQ
Describe and summarize the visualization
Make sure your users have the information they need to effectively read and interact with the visualization. Provide a text overview of the data. Include a descriptive title, a summary of the information, including trends or conclusions, links to table data and other information to orient the user. If your data visualization is interactive, include instructions on using any filters, queries, or other interactive elements.
Provide alternative text
Include descriptive alt text for images and charts. This allows screen readers to narrate the content to visually impaired users. Be detailed but concise in your descriptions. For complex visualizations, your alt text might consist of a summary and a link to a lengthier description.
Use Descriptive Titles and Labels
Provide clear, concise, and visible titles, headings, and labels for each element in your visualization. This is especially important to help users understand the purpose of filters, form fields, and other interactive elements.
Use color combinations that provide sufficient contrast
Insufficient contrast, such as yellow text on a white background, can make it difficult for your users to read and understand your data. Use a tool like the Color Contrast Analyser to ensure that your background and foreground colors combine for a clear and legible presentation.
Check keyboard operability
For equitable access, users must be able to use a keyboard to complete any task that can be completed with a mouse. Users should be able to navigate your data in a logical, linear order, and operate any interactive elements. Before you publish your visualization, unplug your mouse and use your tab, enter, and spacebar keys to navigate your application and activate any forms, filters, or other controls.
Provide data in alternate formats
No matter which tool you use, it's likely you will need to provide your data in an alternate format. To ensure that everyone has useful and unimpeded access to your information, provide a version of your data in a highly accessible format like HTML5. Include a summary of the information as well as tables and other important information. Describe trends and conclusions, if any.
As with the visualization itself, you will need to be sure that any alternate equivalents exported from your data tools are accessible.