Explain every abbreviation where it first appears
An abbreviation is a shortened form of a word, a phrase, or a name. G102 asks you to make sure a reader can find out what yours stand for, and spelling the term out at first use is the usual answer. Sometimes the expansion is no help by itself. W3C points at cases like e.g. and a.m., which expand into Latin, and says give the plain explanation instead. A glossary can carry the whole set. W3C lists this as a sufficient technique for 3.1.4 Abbreviations, a Level AAA rule, so it is a step past Level AA rather than part of it. One route is weaker than it looks. Marking a term with the abbr element and a title attribute stays advisory in W3C's own listing, because a title never reaches keyboard-only or touch-only readers.
How we find it in an audit
A scanner can list every abbr element and every run of capitals that looks like an acronym, which gives our reviewers a starting set. It cannot settle the two questions that matter. Does the expansion exist somewhere the reader will actually meet it, and is the term obscure for the audience you have rather than the one you imagined? Our reviewers work through the key pages and answer both by hand.
How affected users experience it
Screen readers pronounce an unexpanded abbreviation by guessing, so a term like eGFR arrives as noise rather than a word. The listener now has two jobs, decoding the sound and following the sentence. The sentence usually loses. Readers with cognitive disabilities and anyone new to the subject hit the same wall for a different reason, because a letter string carries no meaning until somebody supplies it. Spelling it out once costs a few words and removes the problem.
Passes vs. fails
Passes
The first mention reads 'estimated glomerular filtration rate (eGFR)', and later mentions use <abbr title="estimated glomerular filtration rate">eGFR</abbr>.Fails
A medical results page displays 'eGFR 92' and the expansion appears nowhere on the page or anywhere else on the site.
Other ways to satisfy this rule
7 guides on this site are filed under 3.1.4 Abbreviations. W3C lists this one as sufficient for that rule when it is implemented through a more specific technique, so the condition is part of the test rather than a footnote to it.
- G55sufficientLink unusual words to their definitions
- G62sufficientProvide a glossary for specialized terms
- G70sufficientOffer a dictionary search for specialized content
- G97sufficientExpand each abbreviation at its first use
- PDF8sufficientProvide expansions for abbreviations in PDFs
- H28advisoryExplain abbreviations with the abbr element
This guide is our interpretation of W3C technique G102: Providing the expansion or explanation of an abbreviation. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.