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Systematic reviews

A brief overview of systematic reviews and resources to support producing one.

Resources to search

Finding relevant resources to search for a systematic review

Sources to search:

  • Bibliographic databases
  • Grey literature and internet
  • Scanning reference lists from relevant studies
  • Searching key journals and conference proceedings (called hand searching)
  • Citation searching
  • Contacting study authors, experts, manufacturers, and other organisations

Bibliographic databases

Bibliographic  databases

Depending on the topic there will be a core set of databases which represent the key resources to search for a systematic review. There is no set number of resources to search , only that the search is expansive and comprehensive.

Where to to find appropriate bibliographic databases:

Tips for finding relevant databases

 Look at systematic reviews that are similar to your research topic to see what databases they have used for their searches

 Starting with a known good reference use Ulrichsweb to see what databases index that journal.

Grey literature and internet sources

Grey Literature needs to be considered for a systematic review as it may broaden the scope of the evidence available. Grey literature searching has a number of challenges due to the uncontrolled nature of the sources and the changing types of material that are now considered grey literature. There is a library guide on grey literature that is a good place to start.

Other sources

Hand searching

Hand searching is searching through a journal title for relevant articles. It is slow and time-consuming, but the principle behind it is that not everything is captured or indexed. With electronic sources this is easier in that the journal can be searched with keywords and advanced search tools. This is best done on very relevant journals that are not indexed in databases.


Snowballing is the process of examining the references (footnotes and bibliographies) of known documents to identify other relevant literature. In a systematic review this is typically done in the phase where articles are reviewed. The value in this process is for references which may lie outside of traditional indexing resources.