Primary Research Articles

Primary research articles report on a single study. In the health sciences, primary research articles generally describe the following aspects of the study:

• The study's hypothesis or research question
• The number of participants in the study, generally referred to as the "n"
  • Some articles will include information on how participants were recruited or identified, as well as additional information about participants' sex, age, or race/ethnicity
• A "methods" or "methodology" section that describes how the study was performed and what the researchers did
• Results and conclusion section

Secondary Research Articles

Review articles are the most common type of secondary research article in the health sciences. A review article is a summary of previously published research on a topic. Authors who are writing a review article will search databases for previously completed research and summarize or synthesize those articles,  as opposed to recruiting participants and performing a new research study.

Specific types of review articles include:

• Systematic Reviews
• Meta-Analysis
• Narrative Reviews
• Integrative Reviews
• Literature Reviews

Review articles often report on the following:

• The hypothesis, research question, or review topic
• Databases searched-- authors should clearly describe where and how they searched for the research included in their reviews
• Systematic Reviews and Meta-Analysis should provide detailed information on the databases searched and the search strategy the authors used.Selection criteria-- the researchers should describe how they decided which articles to include
• A critical appraisal or evaluation of the quality of the articles included (most frequently included in systematic reviews and meta-analysis)
• Discussion, results, and conclusions

Determining Primary versus Secondary Using the Database Abstract

Information found in PubMed, CINAHL, Scopus, and other databases can help you determine whether the article you're looking at is primary or secondary.

Primary research article abstract

• Note that in the "Objectives" field, the authors describe their single, individual study.
• In the materials and methods section, they describe the number of patients included in the study and how those patients were divided into groups.
• These are all clues that help us determine this abstract is describing is a single, primary research article, as opposed to a literature review.

Secondary research/review article abstract

• Note that the words "systematic review" and "meta-analysis" appear in the title of the article
• The objectives field also includes the term "meta-analysis" (a common type of literature review in the health sciences)
• The "Data Source" section includes a list of databases searched
• The "Study Selection" section describes the selection criteria
• These are all clues that help us determine that this abstract is describing a review article, as opposed to a single, primary research article.

Full Text Challenge

Can you determine if the following articles are primary or secondary?

Article 1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5368578/

Article 2: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6647066/