Imagine that you’re browsing an eCommerce website. You search for t-shirts, and the website presents you with several options. You find a shirt that you like and add it to your cart.
Suddenly, the website opens a pop-up window, which automatically scrolls to a form requesting your payment information. Would you feel comfortable completing the purchase?
Probably not. As an internet user, you have certain expectations about how websites should operate; you expect “add to cart" to add the product to your cart — and you expect that you’ll be able to keep browsing the website. You expect the checkout process to start without opening a new window, and you expect that you’ll remain in control of your scrollbar.
When websites defy these expectations, it’s usually bad for the user experience (UX). It’s also disastrous for accessibility.
About 26% of U.S. adults live with some form of disability, and those disabilities affect each person in profoundly different ways. People acquire habits and use different technologies to make browsing easier. When you surprise your users, you force them to change their behavior — and you give them less control over the ways that they engage with your content.
Great UX uses the principle of least astonishment
The principle of least astonishment (POLA) is a crucial concept of hardware and software design. The basic idea: Each part of a system should behave in a way that most users expect it to behave.
Most web developers and designers are aware of the idea of POLA. Unfortunately, they often imagine a “typical" user when making decisions — invariably, this means a person with sight and hearing who uses a keyboard and a mouse to browse.
But this isn’t an inclusive approach, as it ignores the experiences of a large number of users. Some people use screen readers (software that converts text to audio). Some people don’t use a mouse. Some people have hearing disabilities, and others choose to turn their sound off when browsing.
To deliver a great experience, you’ll need to consider all of these users when developing your product. You’ll also need to think about ways that your decisions might astonish these users — and whether they’ll return to your website after having a bad experience.
Related: Web Design and Accessibility: Basics Every New Designer Should Know
Many UX decisions cause browsers to behave unexpectedly
So, what features might disrupt the experiences of users with disabilities?
We’ve written hundreds of articles detailing potential accessibility barriers, but some “surprises" are especially common:
Autoplay media. When media starts playing as soon as a page loads, it annoys users — including those without disabilities — and poorly implemented playback controls are especially frustrating.
Missing captions and transcripts. On the modern internet, people expect a text alternative for videos with important sound. If captions and transcripts aren’t available, the media is inaccessible to a sizable portion of your audience.
Automatic change of visual focus. In some cases, it’s okay to automatically move the user’s focus to a form field — but generally, it’s a bad idea that detracts from the UX.
Content that doesn’t reflow. Responsive design is essential; if websites aren’t responsive, some users may be forced to scroll in two directions to read text.
Content that changes default keyboard operation. Disabling hotkeys or keyboard navigation can make navigation much more difficult, and in some cases, users may not know how to regain control of their browsers.
These issues can be avoided by simply thinking about the real-life experiences of your users when designing your content. There’s also a rulebook: the Web Content Accessibility Guidelines (WCAG).
Related: The Most Common Web Accessibility Issues to Avoid
WCAG helps developers avoid surprising their users
WCAG is published by the World Wide Web Consortium (W3C), which also maintains standards for HTML/XHTML and CSS. The guidelines consist of success criteria, pass-or-fail statements that content creators can use to evaluate accessibility.
Following WCAG can help you give your users more options — and avoid disrupting the methods that they use to interact with your website. For the best possible user experience, you should also incorporate UX personas with disabilities in your planning process and train your team with an accessibility-first mindset.
At the Bureau of Internet Accessibility, our goal is to help teams understand the importance of accessibility and achieve their digital compliance goals. To get started, evaluate your website against WCAG’s Level AA success criteria with our free automated analysis. For additional guidance or to discuss a specific feature, send us a message to connect with an expert.