Search strategies for systematic literature searches can often appear complex and difficult to understand. This section of the guide runs through some search techniques in practice, using a search strategy from a Cochrane systematic review as an example.
Sometimes searchers often choose to focus their search, limiting their searches to specific database fields to increase the relevancy of search results. Many systematic searches target the title and abstract fields of a database record.
You can identify when a search has been run on specific fields as these search lines often have codes before or after the search term (i.e. ti,ab OR TIAB). You can decifer which fields are being searched in a strategy by looking at the field code on each search line alongside the help guide for the database that the authors have searched. This should provide a key to all the database fields and their corresponding field codes.
Understanding database fields can help you interpret the complex search strategies used for systematic reviews. A list of database fields for Ovid Medline is available which details all of the fields available for Medline on this platform. The default search field in Ovid advanced search is mp (multi-purpose) which searches across a range of different fields, including title and abstract.
The image below shows an article record in Ovid Medline, so you can see where the different fields appear in an article record:
The ‘adj6’ operator indicates within six words;
‘$’ indicates truncation;
.mp. indicates a search of title, original title, abstract, name of substance word and subject heading word.
Higgins JPT, Green S (editors). strategies, Box 6.4.f. Cochrane Handbook for Systematic Reviews of Interventions. Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.handbook.cochrane.org.
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