Redundant Entry
Information previously entered by or provided to the user that is required to be entered again in the same process is either auto-populated or available for the user to select, except when re-entering the information is essential, is required for security, or the previously entered information is no longer valid.
In plain language
If someone already provided a piece of information at one step of a process (like their address), they shouldn't have to type that same information again at a later step — the system should either auto-fill it or let them pick from what was already given.
Why it matters
Typing the same information over and over is tiring for anyone, but it can be a real barrier for people with motor disabilities (every extra field is more effort) or cognitive disabilities (remembering and repeating data takes more attention). Reusing what's already been provided saves effort and avoids repeated typing errors.
In practice
Fails this criterion
A checkout asks for the shipping address in step 1, then asks for the same address again in step 3 for billing, with no option to reuse what was already entered.
Meets this criterion
There's a "Billing address same as shipping address" checkbox that, once checked, automatically fills in the fields with the information already provided.
Test it yourself
Go through a multi-step process (sign-up, checkout, a long form) and notice whether any piece of information is asked for more than once. If it is, check whether it's already pre-filled or there's an easy way to reuse it, instead of typing it all over again.