If you are searching for an update of a review, you should have the search strategies and search methods used for the previous version to hand.
Before you run the searches again, review the previous methodology, considering whether the databases searched were useful and approrpriate, whether they are still accessible and relevant, and whether any other resources should be included in the update.
It is useful to review at least the MEDLINE strategy with the update team (which may not include the original authors) and ask for their views on the terms used. They may be able to suggest extra relevant and / or newer terms. Check that relevant index terms have not changed or been added since the strategy was last run, and whether the most recent randomised controlled trial filter is being used.
Limiting by date for update searches can be difficult. Limiting by publication year runs the risk of missing older journal articles which have been added to a database since the last searches were run. Limiting by entry date (.ed in MEDLINE and .em in Embase) can become complicated because these dates can change when records are revised, and some records in Ovid's In-Process & Other Non-Indexed Citations MEDLINE segment don't have entry dates, so would not be retrieved using this syntax. It is recommended that you use "date delivered" in Embase (.dd) and if you use entry date limits in Ovid MEDLINE it is recommended that you search the In-Process & Other Non-Indexed Citations file separately (see section 6.4.12 of the Cochrane Handbook).
If changes to the search methods or strategies are made for an update of a review, the reasons can be described in the section in the review on Differences between protocol and review. For further information on the issues you need to consider when updating a search, see section 6.4.12 of the Cochrane Handbook.
The CIS Support team have worked with CIS colleagues, the copy-edit support team and the MECIR standards and Cochrane Style Manual to create template text for search methods in an update. Use of the text is optional and it can be adapted to reflect a Group's local practices. The text is available on the Information Specialists Portal, under the section on Searching: reporting.