This resource is an archived version of the Readability Guidelines.
New wiki is at: readabilityguidelines.myxwiki.org
Go to the Abbreviations and acronyms page.
Recommendations
Abbreviations and acronyms are not great for readability, except where users know the thing better by its short name term, for example GIF, MB, KB. But it’s dangerous to make assumptions about what is well known for your users. VAT may not be known to users who have English as a second or third language.
Language is organic. Some words in used in everyday speech derived from acronyms. For example, laser, scuba, radar.
1. Do not use points in abbreviations, or spaces between initials, including those in proper names: mph, 4am, WH Smith.
2. Write out 'for example' and 'that is' in full, do not use 'eg' and 'ie'. Do not use 'etc'. These are all abbreviations of Latin terms and so are not readable and inclusive for all users.
3. Test with users to find out how familiar things are to them. You may need to include a brief description, for example "the conservation charity the RSPB" instead of "the RSPB".
4. Use all capitals if an abbreviation is pronounced as the individual letters (an initialism), for example BBC, CEO, US, VAT. Spell out with initial capital, if it is an acronym (pronounced as a word), for example Nasa, Nato, Unicef, unless it has entered into everyday language, for example laser and radar.
5. Capitalise single letters in expressions like C-list, F-word, “the word assassin contains four Ss”.
6. An international audience will not necessarily be aware of abbreviations that are very familiar in the country of authorship.
Still under discussion:
7. If an abbreviation or acronym is to be used more than once, put it in brackets at first mention, for example Association of Chief Police Officers (Acpo), seasonal affective disorder (Sad). If an organisation is mentioned only once, it is not necessary to give its abbreviation or acronym.
If you follow 7. then:
With a well-known acronym give the acronym first then the full wording, for example BBC (British Broadcasting Corporation). Reverse the order with a less-familiar acronym – give the full wording first.
Considerations
Writing out the acronym in full on first use is a common style guide recommendation, but it may not be sufficient as readers may only reader part of your page and miss the written in full version.
Acronym markdown, where the full explanation is available as hover text, is a good idea if you have that functionality. GOV.UK explain this under ‘A’ of their style guide.
Usability evidence
GOV.UK Style Guide A to Z, UK Government website
Guardian and Observer style guide: A, 2015
'Do acronyms belong in the medical literature?', 2016
'Alienating the Audience: How Abbreviations Hamper Scientific Communication', 2017
I've been looking for research that might show evidence that acronyms and abbreviations might make it harder to read and understand the meaning of a sentence.
The best I could find is this paper, Do acronyms belong in medical literature? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081004/
TLDR summary quote: "Although acronyms might save space and sometimes might increase reading speed when they are familiar, there is little evidence that they increase readability and abundant information to the contrary."