Conducting a Literature Review

Supplemental search methods include strategies that explore credible content, such as:

1. Grey literature: includes credible white papers and other reports, dissertations and theses not published in commercial journals or books.  

2. Citation relationships:

• scan  reference lists of articles, books, dissertations and theses, access studies cited in knowledge syntheses e.g. systematic reviews and literature reviews,
• use database limiters to conduct searches for  similar articles,  co-cited articles and  forward citation searching  

3. Pay attention to:

• authors who publish on the topic more than once
• take note of those author’s keywords
• look in the article bibliography for other articles to consider
• look for the original research on a topic by following the citations through the bibliography and journal titles

4. Hand searching: a physical copy of a published journal can reveal content excluded from the indexing of an online journal. This method is handy for elusive topics with little obvious literature in online databases or indexes, e.g. PubMed, and ERIC.

4. Clinical Trials registries often report on content not reflected in the published literature. The US Government and the World Health Organization provide clinical trials with searchable registries.

• International Clinical Trials Registry Platform (WHO)
• ClinicalTrials.gov

5. Direct author contact is useful for

• more information about clinical trials,  
• following up on current research not yet published
• gaining access to an article not found in the university library
• accessing important works that are older and not readily available without paying.  

Contact information is found in a variety of ways:  in online articles, in databases as part of the article data, searching on research instrument information in a database, accessing institutional contact lists or websites and through professional sites such as LinkedIn.

Grey literature is not published in the traditional sense and includes content such as:  clinical trial data, government documents, theses, conference proceedings

• it is essential to include in your reviews to
  • broaden the scope and ensure the review is as thorough as possible
  • reduce publication bias and find sources for negative results 
  • include emerging research
  • discover more references that your database search might have missed

Where to Find Grey Literature

1. Use association, organization and government websites to locate unpublished content. Consult the library program guides for ideas. e.g. Nursing and Healthcare Resources.
2. Likely locations of grey literature include Clinical Trials Databases, Government Documents, Institutional Repositories, Conference Proceedings, Theses and DIssertations, Public Health Authorities