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DHYG: Dental Topics

Top Databases for Narrative Review

Primary Research

Primary research is information presented in its original form without interpretation by other researchers. While it may acknowledge previous studies or sources, it always presents original thinking, reports on discoveries, or new information about a topic.

Primary Sources include:

  • Pilot/prospective studies
  • Cohort studies
  • Survey research
  • Case studies
  • Lab notebooks
  • Clinical trials and randomized clinical trials/RCTs
  • Dissertations

For most research articles, you'll find all of these elements as headings and subheadings:

  • Method -  explains how the research was designed and carried out; identifies the population studied; explains how the data was collected 
  • Results - gives an analysis of the data
  • Discussion – includes limitations of the research (what went right and what went wrong)
  • Conclusion - explains how the research was either conclusive or inconclusive and what might be the next step
  • References –gives credit to the other scholars in the "conversation" and is a potential gold mine of more articles on this topic for your reader

Secondary Research

Secondary sources are best identified by their use of primary articles as source material.

Secondary sources, especially systematic reviews, are written under specific guidelines and protocols and often include methods sections and abstracts. So the presence of these sections are not necessarily an indication of a primary source. 

Secondary Sources include:

  • Method - explains what databases were searched, date range of article searches and number of articles included in review
  • reviews, systematic reviews, meta-analysis
  • newsletters and professional news sources
  • practice guidelines & standards
  • clinical care notes
  • patient education Information
  • government & legal Information
  • monographs
  • entries in nursing or medical encyclopedias

Grey Literature

The term grey literature refers to research that is either unpublished or has been published in non-commercial form.

Examples of grey literature include:

  • Government reports

  • Policy statements and issues papers

  • Conference proceedings

  • Pre-prints and post-prints of articles

  • Theses and dissertations

  • Research reports

  • Geological and geophysical surveys

  • Maps

  • Newsletters and bulletins

  • Fact sheets.

Academics, pressure groups, and private companies are only some of the sources of grey literature.

Much grey literature is of high quality.

Grey literature is often the best source of up-to-date research on certain topics, such as rural poverty or the plight of unhoused people in Victoria.

In the health sciences, grey literature is vital for developing a more complete view of research on a particular topic and for producing systematic reviews and other rigorous approaches to evidence synthesis. Grey literature can be a good source for data, statistics and very recent research results.

Because there's no publisher-enforced limitation on length, these reports can be much more detailed than the journal literature. They can help to offset issues related to publication bias, such as:

  • Publication lag  Results of studies may appear in grey literature, such as conference proceedings, a year or more before they appear in a peer-reviewed publication.

  • Positive result bias  Study results that show a negative or no effect are published in scholarly journals less often than those with a positive effect. Those negative results may be found by reviewing the grey literature.

Grey literature is particularly important in the area of health policy, where health technology assessmentseconomic evaluations, health systems impact assessments and comparative effectiveness research are of special interest.