Sources to search
Systematic reviews require a comprehensive and reproducible search of a wide range of sources to identify as many relevant studies as possible. An exhaustive search process minimises the risk of biased reporting of results and thereby strengthens review validity.
The systematic review search should therefore:
- seek to identify unpublished as well as published studies
- be iteratively developed in one database and then accurately translated for all other databases
- include a search of the internet outside databases using a search engine such as Google
- be run just once and the retrieved citations taken offline into a reference management program such as EndNote. The date on which the search is run must be recorded as part of documenting the search strategy.
The selection of electronic databases and unpublished sources to search will depend upon the review topic. Your liaison librarian will have specialist knowledge in this area.
In addition to searching databases, consider trying the following approaches to identifying studies:
- Looking for grey (unpublished) literature
- Checking reference lists of relevant articles for other relevant studies (snowballing)
- Google searching using the Google Advanced search option for better results. Limit to filetype PDF to restrict results to documents, reports etc. rather than blogs and websites.
- Handsearching a select range of specialist journals and conference proceedings closely aligned with your topic of interest.
- Identifying experts in the field and contacting them for information about other studies or data.
- Some journal titles are not indexed in the major databases
- Some sections of journals (e.g. meeting abstracts) are not indexed
- Indexing is a fallible process. Citations can have the wrong subject headings assigned or relevant subject headings can be missed rendering a citation difficult to find via an electronic database search.
- To avoid relying completely on your search strategy.
For more information on specific journals:
Other subject-specific databases