Ensure that the data message in a visual is accessible in 3 ways: chart, table, sentence.
We want to ensure that all users can learn and interact with data. Often one visual may be great for some users, but inaccessible for others.
The best case scenario here is to have a text-based equivalent of every data visual. This text summarizes and explains the visual and key findings. Learn more about the importance of defining key findings.
At the minimum, include a table of the summarized data on your dashboard below the figure(s). Test your tables with your keyboard and a screen reader. Find some examples of tables in our gallery.
Choose data visualizations that are familiar to viewers.
In general, beware of overly complicated graphs. The increase in cognitive load for users trying to decipher a new type of visual may not be worth it.
Test your visuals to ensure everything is large enough to view and click. Tiny shapes or widgets are difficult to click.
Aim to use vetted, widely-used visuals. Smaller, homegrown, custom visuals may not be reliable enough for public reporting (or may require additional purchase).
Maps are particularly challenging and should be tested for accessibility and color contrast.
Power BI tip: For point maps, feel free to use Power BI’s Bing map - but ensure the color of your points contrasts sufficiently with the light grey background. Using the dark blue is best.
Power BI tip: Visuals change often. In Power BI, we recommend using the built-in visuals. Custom visuals are less reliable and often lack robust accessibility features and are not appropriate for publication.
The only exception to this rule is for choropleth maps. For choropleth maps, the Mapbox mapping visual is the best option in Power BI, though it does come with specific challenges. The Power BI template includes several examples and several important specifications for these maps.
Do not put text or explanatory content within the dashboard where it cannot be translated.
Your dashboard should contain data visualizations and any necessary supporting widgets (like filters or slicers). All other supporting content, like explanatory information or data notes, should be embedded into the webpage directly. It should not be inside your dashboard where it is harder for translations and screen readers to access.
The only text that may be included on the dashboard is the name of the publisher “City and County of San Francisco” and information on the refresh date or schedule.
Power BI tip: Power BI dashboards typically have a thin black focus indicator. Use our template with the light grey background. Do not use dark dashboard backgrounds, because the black focus indicator will not contrast sufficiently.
Minimize use of decorative images and shapes.
Avoid using too many decorative shapes to the point where they are distracting.
Test your dashboard with a screen reader as you develop the dashboard.
Ensure that you can navigate and get all key information using a screen reader. Ensure the alt text reads any keyboard instructions needed to access the visual or data.
When embedding Power BI dashboards onto SF.gov, the keyboard instructions appear automatically when a user tabs through the website.