Predictable Interfaces and Consistent Help
Avoid unexpected context changes and keep repeated navigation, component identification, and help mechanisms consistent across a process
Predictability covers several distinct requirements. Focus alone must not trigger a context change (3.2.1). Changing a setting must not unexpectedly submit, navigate, or substantially change context unless users are told beforehand (3.2.2). Repeated navigation and components with the same function must remain consistent (3.2.3 and 3.2.4). When help mechanisms are provided across pages, they must remain in the same relative order unless users initiate a change (3.2.6).
The criteria do not prohibit dynamic interfaces. They require changes to follow explicit user actions or be explained before the control is used.
Unexpected Context Changes vs. Explicit Actions
View inaccessible code
<a href="/checkout" onfocus="location.href='/checkout'">Checkout</a>
<select onchange="form.submit()">…</select>View accessible code
<a href="/checkout">Checkout</a>
<label for="country">Country</label><select id="country">…</select>
<button type="submit">Apply country</button>System-level checks
Compare templates across a representative set of routes and process steps. Record the order of repeated navigation and help mechanisms, and verify that controls with the same icon or label perform the same function. Test focus and input changes without a pointer.