An amendment to a Cochrane review is any modification or edit (including withdrawal) that does not include an update. The review is then said to have been amended. Examples of amendments include any or all of the following in the absence of a new search for studies: (i) a change in methodology; (ii) the correction of a spelling error; (iii) the re-writing of a Background section; (iv) the full inclusion of a study that was previously ‘awaiting classification’; or (v) the changing of conclusions on discovery of a major coding error. A Cochrane review may receive an amendment at any time. An amendment can involve much or little work, and result in big or small changes to the review.