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Introduction to systematic reviews

Replicating the search across different databases

You will need to replicate your search across the different database searched. Your keywords will be the same across the different databases but you will need to find out the relevant controlled vocabulary terms in each database by using the thesaurus to identify what these are. If the database does not have a thesaurus of controlled vocabulary terms, then you can only use the free-text keyword searching within this database.

You will also need to check the help-guide within the individual database to check the syntax used for truncation, wildcards, proximity limiters, etc. as these may vary across databases.

Database help-guides include:

EBSCO databases (MEDLINE, CINAHL, PsycINFO, ERIC, SPORTDiscus, etc)



Web of Science

Proquest databases

Keyword search operators

When formulating the search terms for the keywords, the following devices can be really useful:

Truncation - this is when the root of a word is entered following by a symbol - typically an asterisk (*) but the syntax can vary across different databases. This instructs the database to search for all keywords which begin with that root.
For example: autis* would search for autism, autistic, Autism Spectrum Disorder, etc. This saves you having to enter each term separately and means you won't miss out on any relevant results if you hadn't entered that specific version of the keyword.

Phrase searching - this is when speech-marks are used around a particular phrase (so two words or more) which directs the database to search for that specific phrase with the words in that order (rather than two separate keywords) - e.g. "language development".

Wildcards - this is the replacement of a letter with a symbol - typically a question mark (?) but again the syntax can vary across databases, for example, wom?n would search for woman or women.

Proximity/Adjacency operators - proximity or adjacency operators allow you to search for a word within a specified number of another word of your choice. This is less precise than a phrase search but ensures it is more likely that the words/phrases will be related than a simple AND search. Different databases require you to type in different operators/commands in order to undertake a proximity search. Check the help pages for the database platform you are searching.

Field searching - Most databases will allow to specify in which field of an article record that you would like to search.  For example, you could restrict your search to just the title or abstract, which could increase the precision of your search.

Methodological filters

ISSG Search Filters Resource

The InterTASC Information Specialists' Sub-Group Search Filter Resource is a collaborative venture to identify, assess and test search filters designed to retrieve research by study design or focus. The Search Filters Resource aims to provide easy access to published and unpublished search filters. It also provides information and guidance on how to critically appraise search filters, study design filters in progress, and information on the development and use of search filters.

Saving your searches

Most database providers will allow you to save your searches and it is advisable to do so, in case you need to re-run a search at a later date or if you realise that you have omitted a keyword or subject heading from your search strategy.