Consistent Identification
The same function has to be identified the same way across a set of pages, so a control that adds an item to the cart cannot be Add to Cart in one place and Buy in another. Same function means same result when it is used. What the rule asks for is consistency, and consistency is not the same as being identical. Go to page 4 and Go to page 5 are consistent. Print receipt and Print invoice are consistent, and they differ because the functions differ. Identification here means the accessible name as much as the visible label, which is why two buttons that look the same and carry different aria-label values fail a rule a visual review would pass.
Why it matters
Every renamed function asks the user to do a small translation. Is Bag the same thing Cart was on the last page? For a user with a cognitive disability that translation may not happen, and the function goes missing. For a screen reader user, two names are two things, because nothing they hear says otherwise. There is a quieter benefit as well. A screen reader user can search a page for a control by its name, and that only works while the name stays the same. Keep the vocabulary steady and a hundred pages become one interface somebody learns once.
Who this rule protects
Users with cognitive disabilities need a function they have already learned to look the same next time. Screen reader users rely on that same familiarity, and they lose the ability to find a control by searching for its name when the name keeps moving. People who find text hard to read get the most out of consistent icons, because a familiar icon lets them skip the words entirely, and that only holds while the icon means one thing.
How to check it yourself
- List the functions that recur across the set, such as search, cart, save, share, print and download.
- Compare the visible label, the icon and the accessible name for each one on every page it appears on. Check the accessible name last and trust it most, because it is the one a screen reader reads.
- Judge consistency rather than sameness. Labels that follow one pattern and vary only where the function varies, such as Print receipt and Print invoice, are doing what the rule asks.
- Where one icon serves two different functions, check the two carry different names. A check mark meaning approved in one place and included in another needs two text alternatives, not one.
- Fix the names before you fix the consistency, since a control with no accessible name has nothing to be consistent about.
Failures we see most often
- The same action reads Add to Cart on product pages and Buy on category cards, so a user who learned one has to work out that the other is the same thing.
- Two buttons look identical and announce differently, because one carries an aria-label the other does not. Only assistive technology users ever meet this one.
- A search button is labeled Search on the site and Find in the help section, which is W3C's own example of one function named two ways.
- One icon does two jobs and carries one text alternative, so a screen reader user hears the same word for two different outcomes.
Who this one is for
Read from this rule's own note above, so the grouping and the note cannot disagree.
- Blind and screen reader userspeople who cannot see the screen
- Cognitive and learningpeople for whom the difficulty is understanding, remembering, or staying with it
How to fix it
- Pick one name per function and hold it across the set, then enforce it through a shared component library rather than through everybody's memory.
- Make the accessible name match the visible label, so the word one user hears is the word another user reads.
- Where labels have to vary, vary them in a pattern. Download followed by the document name is consistent even though every instance reads differently.
- Give the same icon a different name wherever it does a different job, because the name is what tells a user which job it is doing this time.
Step-by-step fix guides (2)
Passes vs. fails
Passes
It is Favorites everywhere, with the same heart icon and Favorites as the accessible name behind it on every page in the set.
Fails
The saved-items feature is Wishlist on one page, Favorites on another, and an unlabeled heart on a third, so a user has to guess whether all three are the same thing.
In audits and lawsuits
We inventory every recurring function across the audited pages and compare its label, its icon and its accessible name. The accessible name is where the findings hide. Two buttons that read Send to a sighted user and announce Send and Submit to a screen reader are the exact case W3C names as a failure only assistive technology users ever meet. No visual review will catch it. We also check the criterion is the right one before raising it, because consistent does not mean identical, and a set of links reading page 2, page 3 and page 4 is doing this correctly. There is no automated rule here. There is a dependency worth planning around, though, because the technique that satisfies this rule also requires the naming techniques of 4.1.2 and 1.1.1. Fix the names first, then make them consistent.