In his The Tipping Point: How Performance Decisions Make Accessibility Differences presentation at Inclusive Design 24 2019 this month, Henri Helvetica discussed the relationship between performance and inclusive design.
A designer who works in Toronto, Ontario, Canada, he explained how performance metrics like
- Time To Interactive
- Wait time anti-patterns
- Resource management
impact inclusive design and how people are included.
His 50-minute presentation is available on YouTube, currently with English captions.
Short on time? Here are my quick takeaways.
- Web performance is framed as a user experience issue. What is the user’s perception of the site? How responsive is it? Did it load quickly?
- Similarly, accessibility is a performance issue. Can users complete tasks? What is their perception of the site? Are buttons large enough? Can users easily navigate the page?
- When web performance is slow, everyone suffers. Reducing latency (delay before data is transferred) is important.
- In 2016, mobile usage passed desktop usage. The fastest growth in users are users in emerging markets, users who are mobile-only and on mid-to low-end digital devices.
- Of the people in the world that have disabilities, 80 percent live in the global south/ emerging markets. ~ Nithya Sambasivan
- Network connections for people in emerging markets: 4G is 29 percent, 3G is 31 percent, 2G is 40 percent requires you consider speed while creating inclusive designs. As well as small screens, low memory, and cost of data.
- When it comes to performance, it’s all about resources. Images are the largest resource on a page as well as the number two issue for accessibility.
How Performance is Improving User Experience and Accessibility
- Over the years, YouTube has made significant performance improvements. One of the most important improvements is YouTube deploying adaptive bitrates, which are adjusted based on user’s network connection.
- The Network Information API: you can poll the network, figure what kind of network it is, whether it’s fast or slow, allowing you to make decisions on what resources to send to users. Think of traveling on a train, where the network is slower.
- Another solution for improving web performance: reduce number of images on your site.
- Time To Interactive (TTI) measures how long it takes a page to become interactive. Think of when a user selects a “Buy” button, but nothing happens.
- Code coverage: is there a method to manage the amount of code being sent to the user? Reduce the amount of code by filtering out objects you don’t need so information can reach assistive technologies.
- Web fonts impact performance, depending on how many you load. Keep in mind italic styles makes reading more difficult. (What’s New in Android Accessibility, Google I/O 2019: 40 minute video)
- People use old devices, old operating systems, old browsers. Create simple and inclusive designs, consider carefully whether you include experimental or more modern features.
- When something on the web doesn’t work well for people with no disabilities, that pain point is amplified for people with disabilities.