Step 3 Search for evidence

"The search strategy for a scoping review should ideally aim to be as comprehensive as possible within the constraints of time and resources in order to identify both published and unpublished (gray or difficult to locate literature) primary sources of evidence, as well as reviews. Any limitations in terms of the breadth and comprehensiveness of the search strategy should be detailed and justified." (JBI Manual for Evidence Synthesis, Chapter 11.2.5 Search Strategy)

JBI recommends a three step process in developing a search strategy:

1. The first step is an initial limited search of at least two appropriate online databases relevant to the topic.
2. This initial search is then followed by an analysis of the text words contained in the title and abstract of retrieved (relevant) papers, and of the index terms used to describe the articles. A second search using all identified keywords and index terms should then be undertaken across all included databases.
3. The reference list of identified (included) reports and articles should be searched for additional sources. This third stage may examine the reference lists of all identified (included) sources or examine solely the reference lists of the sources that have been selected from full-text and/or included in the review.

The general process in developing a search strategy is:

1. Identify key concepts and synonyms related to your research question.
2. Identify the databases and other sources (e.g. grey literature) you need to search. 
3. Identify relevant database subject headings (e.g. MeSH [PubMed/Medline], Emtree [Embase]) and apply to your search strategy.
4. Apply search techniques such as Boolean, Nesting, Phrase Searching, Truncation and Wildcards to create a comprehensive and effective search.
5. Test, review and amend search as required. For example:
   • Consider if certain concepts/keywords require to be searched in particular database fields (e.g. Title/Abstract) to focus search.
   • Consider if certain database filters need to be applied in order to narrow the search e.g. publication dates, age, sex, article type, language etc.

A useful starting point can be to check the search strategies in published scoping reviews for examples of how searches are structured and assist in keyword development.

Your Liaison Librarian can provide you with assistance in developing search strategies (staff/HDRs).

Scoping reviews require a meticulous documentation of their search strategy to enable a clear and transparent reporting and auditing. Scoping review searches may be iterative as reviewers become more familiar with the evidence base, additional keywords and sources, and potentially useful search terms may be discovered and incorporated into the search strategy.

PRISMA-ScR provides details of the details that need to be recorded/reported for information sources and searching.

Search details which must be recorded are:

• Who developed and executed the searches.
• The date the search was conducted.
• Sources searched, such as:
  • Databases (including the platform) e.g. EBSCO (platform) APA PsycINFO (database).
  • Grey Literature sources.
  • Reference lists scanned of relevant studies.
  • Hand searching a record of the source (for example, Conference proceedings, journal title) and years searched must be kept.
  • Organisations or experts contacted.
• Keywords and Subject Headings used.
• Any limits/filters applied such as language or publication date (including rationale for use).
• Provide the entire search strategy for at least one database either in the text, a table or an appendix

Search result numbers are documented and reported as part of the PRISMA Flow Diagram.

TIP: Most databases allow for the search history to be saved which provides an exact record of the search.

Identify the relevant databases for your review. If you are staff or a HDR student your Liaison Librarian can advise on which databases should be searched and on developing search strategies.

Below are some key/commonly used databases in Health related reviews. See the Health Databases list for more (some databases have a more specific topic focus than others).

Citation chaining involves searching backwards (reference list searching) and forwards (citation searching) for articles directly related to any studies included in your review.

See the following video for more information:

Source: UNSW (CC-BY-NC)

The following databases can be used for citation chaining: