Cochrane Style Manual
When to use abbreviations, acronyms and initialisms

In this section: General usage | In titles or headings | At the beginning of a sentence | In tables or figures

General usage

In this manual, the term 'abbreviation' is used to cover abbreviations, acronym and initialisms. 

Use abbreviations sparingly. Only use abbreviations if they are widely known across the broad readership of Cochrane Reviews, are used frequently in a section or throughout the review, or enhance readability. Consider using an abbreviation only if the term has three or more words. All abbreviations used in the ' Abstract', 'Plain language summary', 'Main text', and 'Authors' conclusions' should be redefined at the beginning of these sections. In figures and tables, all abbreviations should be listed at the end with their definitions. If the review or document is long, it may be sensible to explain each abbreviation in each section of the text.

To use an abbreviation, write the full name in the first instance and follow it immediately by the abbreviated version in brackets. When something is better known by its abbreviation, it may be helpful to include the abbreviation even if the name occurs only once (e.g. World Health Organization (WHO)).

Abbreviations should follow formatting conventions. Some terms, particularly statistical terms, are commonly abbreviated in Cochrane documents (see Common abbreviations), while others should be avoided (see Abbreviations to avoid). See also Frequently used names for names commonly used and abbreviated in Cochrane documents.

In titles or headings

Only the common abbreviations that do not need to be defined may be used in review titles and headings without the full name needing to be written first. When a term used in a title may be more commonly known under its abbreviated form, its abbreviation may be added in parentheses after the fully written term (e.g. 'A study of the World Health Organization (WHO) recommendations for hygiene'). Abbreviations are acceptable in headings if they have been defined previously, though it may be preferable to rearrange the wording of headings to avoid starting with abbreviations.

At the beginning of a sentence

While it is acceptable to use abbreviations at the beginning of a sentence, authors may find it preferable to rephrase sentences to avoid starting with abbreviations.

In tables and figures

It is convenient to abbreviate some words, such as number (no.) and versus (vs), in tables and figures, but it is preferable to write them in full in the review text.