General guidance on the use of punctuation
Symbol | Guidance | Example |
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Brackets/parentheses
| UK English: use round brackets throughout for nested brackets. US English: use round brackets followed by square brackets for nested brackets. | UK English: The standardized mean difference was -0.02 (95% confidence interval (CI) -0.13 to 0.08). US English: The standardized mean difference was -0.02 (95% confidence interval [CI] -0.13 to 0.08). |
Square brackets may be used in chemical formulae, mathematical formulae, edits to quotations, or to indicate an error in the original version of quotation. | pH = -log10 [H+] … as Jones said, "there are very few people who are resistant to [morphine]." (where morphine replaces 'this medication' to ensure contextual accuracy) Smith says "students tend to overlook there [sic] health". | |
Colon
| Follow a colon with a lower-case letter unless the following word has to start with an upper-case letter, specifically, a proper noun or an acronym. | Review topic: cancer Review topic: HIV/AIDS Location: London Location: local hospital |
Comma
| Use of a comma before ‘and’ and ‘or’ in lists is optional, but be consistent. | I have read Cochrane Reviews about malaria, tuberculosis, and vaccines. I have read Cochrane Reviews about malaria, tuberculosis and vaccines. |
Use commas before ‘and’, ‘or’, and ‘but’ in two-phrase sentences (when these words join the two main clauses). | The reviews are written here, but they are available internationally. The reviews are sent here by post, or they are sent here electronically. | |
Dash | There should be one space either side of a dash. | The reviews are sent here by post – or electronically – and then processed. |
Full stop | Use one space (not two) after the full stop. Note: when the publishers format Cochrane reviews, one space is allocated after each full stop. This means if you use two spaces, they will be reduced to one. |
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Hyphen | Hyphens are used to link word compounds with two or more words used as adjectives, such as ‘six-week interval’ and ‘four-dose regimen’. Be aware that hyphens can sometimes change the meaning of a word, such as ‘unionized’ (with a union) and ‘un-ionized’ (without ions). | There was a six-week interval between doses. |
Period | See full stop advice above. |
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Quotation marks
| Use double quotation marks for quoting dialogue and when quoting text from a written source. No other formatting is required for quotations (do not use italics). | In the study “12 participants experienced adverse effects” (Goodwin 1998). |
Use single quotation marks in all other instances. | The ‘standard’ approach is to count only major events. |