Making data accessible in Tableau
US Section 508 is the current standard for publishing public-facing content and uses Web Content Accessibility Guidelines (WCAG) 2.0 to evaluate the accessibility of online content. Tableau makes it easy to create accessible dashboards, especially since its out-of-the-box features meet many of the WCAG test criteria.
However, Tableau’s highly customizable data visualizations mean that it’s possible to design non-compliant dashboards. This article provides some high-level tips for dashboard design and discuss how to avoid common missteps for each of the four WCAG principles.
Making data perceivable is where you have the most latitude to succeed or fail when designing for accessibility. Information should be perceivable by people with poor color sensitivity, poor vision, and people using screen readers. Here are a few guidelines for how, using a mix of good accessibility-focused design and out-of-the-box features, you can produce perceivable dashboards in Tableau.
- Use descriptive titles and Tableau’s auto-generated captions to provide summary text. Edit the captions as needed to provide additional context.
- For text and marks, use colors with high contrast. Black on white for text and Tableau’s Colorblind color scheme for marks both work well here.
- Instead of or in addition to color, use position, shape, or size to encode information.
- Use grouping and aggregation to make simpler views. A viz with hundreds of marks is difficult to read with a screen reader and can be unnecessarily cluttered.
Web pages should be operable in multiple ways. Tableau provides several features supporting keyboard-based operation, visual indicators for focus and the ability to interact with filters.
- Instead of time-based transitions or effects, use interactive filters, tabs, or Tableau’s Story feature so users can step through multi-screen visualizations at their own pace
- Use single select and multiple select filters because they do not require users to have a mouse
- Clearly label viz components instead of using abbreviations or acronyms
- Avoid tooltips on hover for essential information as these are not compliant. Instead, focus on providing summary level detail with well-labeled data points, and drilldown detail on subsequent views
Tableau addresses several of the Understandable criteria out-of-the-box by providing a standard user interface and web pages that can be parsed programmatically. For example, a multi select dropdown filter always looks the same and has relevant tags so assistive technologies can identify the element as a filter.
It can be tempting, however, to layer on complex actions, including set and parameter actions, that make a navigation or filtering unpredictable.
- Avoid complex dashboard actions that can change context in unpredictable ways. Instead, try to provide action links and detail views on separate tabs
- Use Tableau’s native navigation components, such as dashboard tabs, when embedding
- Provide instructions on how to interact with a dashboard
Tableau conforms to the success criteria for the Robust principle out of the box. The main component to think about here is how you are embedding Tableau. If your dashboard is embedded on a non-accessible web page, then the whole page is non-compliant according to US Section 508.
Coming up in this series
This was a high-level view of how Tableau makes it easy to publish US Section 508 compliant dashboards. The next posts will look at each of the WCAG principles in detail:
- Perceivable: Combine Tableau’s out-of-the-box accessibility features with good dashboard design
- Operable: Enable users to interact with the dashboard in several different ways
- Understandable & Robust: Avoid designing overly complex navigation, provide instructions, and don’t have any broken components on your web page