BIO 218: Cellular and Molecular Biology

What is a Primary Research Article?

In a primary research article, author(s) present a new set of findings from original research after conducting an original experiment. Think of what you do in any of your various lab activities. If you were to write a scholarly paper on any of your biology labs (like the Flowers and Pollinators lab from BIO 191), it would be a primary research article.

Primary research articles are also referred to as original research or research articles.

How to Identify Primary Research Article

• Did the author(s) of the paper conduct the experiment themselves? This is the most important thing to look for in order to identify primary research. Look for language that indicates that the author(s) devised the experiment, carried it out, and analyzed the resulting data themselves.
• A primary research article typically contains the following section headings:
  • "Methods"/"Materials and Methods"/"Experimental Methods"(different journals title this section in different ways)
  • "Results"
  • "Discussion"

Here is One Example of a Primary Research Article and How to Determine that it is a Primary Research Article

"Effects of Salinity Stress on Survival, Metabolism, Limb Regeneration, and Ecdysis in UCA PUGNAX"

Read the Abstract

If you read the abstract, you can see that the author(s) themselves conducted an experiment:

• "This study investigated physiological and metabolic changes in the molt cycle of U. pugnax..."
• "For this study, a limb was removed and its regenerative growth was photographed every two days"
• "...crabs were dissected, and the tissues collected were analyzed for their protein and carbohydrate contents."

Read the Headings

• The article has Materials and Methods, Results, and Discussion sections, all which indicate that the authors conducted an experiment and then analyzed the data they found.

Skim the Article

If you skim the article, it is clear that the authors tested a hypothesis using the scientific method. They are only really talking about research that was conducted by others in the "Introduction" section of the article, which is what you would expect for a primary research article.

Look for Textual Evidence

If you skim the article, you can easily find additional evidence that an experiment was conducted by the authors themselves.

• "We collected adult crabs of Uca pugnax for this experiment on 26 August 2006 at Powell's Bay, VA ..."
  • [They collected their sample i.e. crabs.]
• Crabs were exposed to different salinity levels to determine survival and hemolymph osmoregulation ability."
  • [They exposed their sample to different variables.]
• A two-way ANOVA (ɑ=0.05) was performed to determine whether the effects of external osmolarity on hemolymph osmolarity depended on sex."
  • [They used statistical methods to analyze their data.]
• All crabs at the highest (75 ppt) salinity died, but survival for all other salinities was above 83.3%."
  • [They reported the results of their experiment.]
• Our osmoregulation results suggest that U. pugnaxis a hyperosmoregulator at low salinities while an osmoconformer at higher salinities."
  • [They drew a conclusion from their experimental results.]

What is a Review Article?

Review articles do not report new experiments. Rather, they attempt to provide a thorough review of a specific subject by assessing either all or the best available scholarly literature on that topic. By considering the findings of many primary research articles, review articles can provide a comprehensive background and analysis of all the available evidence on a subject. A single review article will summarize, analyze, and discuss the results of numerous primary research articles all at once, and often will provide comparisons with respect to each other.

For a review article, the authors do not design an experiment and carry it out in a lab. Rather, they search for, find, and read numerous primary research articles on a particular topic.  Then, they organize them into a cohesive narrative that provides an overall summary and analysis of a topic.

Review articles can help explain the basics of a particular area of science, provide an overview of all of the research that has been conducted on a particular topic, and/or provide insight into current topics of scholarly disagreement. They can also help identify where there are gaps in research and scientific knowledge.

How to Identify a Review Article 

• Author(s) summarize and analyze previously published research. NOTE: While primary research articles provide a background on their subject by summarizing previously conducted research, this typically occurs only in the "Introduction" section of the article. Review articles, however, will summarize previously conducted research throughout the entire paper.
• Author(s) did NOT do original research. Instead, they summarize and discuss the work of others.
• The article might attempt to (1) explain the basics of, (2) provide an overview of, or (3) shed light on aspects of disagreement or confusion regarding a topic.
• In order to provide insight into aspects of disagreement or confusion surrounding a research topic, the article might focus on a specific research question that has been investigated many times by other researchers. Here, they compare and contrast primary research articles in an attempt to answer a complicated question.
• Do not typically contain sections such as Methods (and Materials) or Results because the author(s) did not do any original research!

Practice: An Example of a Review Article

"Stem Cells, Cancer, and Cancer Stem Cells"

Step 1: Read the Abstract

If you read the abstract, there is nothing to indicate that the authors of this paper conducted an experiment themselves. The authors do not list their hypothesis, methods used to conduct an experiment, or specific results. Rather, it sounds like the authors are trying to provide the reader with an overview of recent research.

Step 2: Read the Headings

If you look through the headings of the different sections of this article (the words that are bolded), they do not indicate that an experiment was conducted by the authors.  This article does not have those specific section headings commonly found in primary research, such as "Materials and Methods," "Results," or "Discussion."

Step 3: Skim the Article

If you skim through the article, there is nothing to indicate that the authors tested a hypothesis in a lab or in the field. Instead, the article weaves together the findings from many primary research articles and then considers what the results could mean when viewed collectively.

Step 4: Look for Textual Evidence

If you skim through the article, there is more evidence that it is a review:

• "Through much of this review we focus on the haematopoietic system because both normal stem cells and cancer cells from this tissue are well characterized."
  • [The article actually tells you that it is a review!]
• Cumulatively, the above findings suggest that Wnt signalling may promote stem cell self-renewal in a variety of different epithelia in addition to HSCs."
  • [The article is summarizing the findings from several studies. REMINDER: While primary research articles provide a background on their subject by summarizing previously conducted research, this typically occurs only in the Introduction section of the article. Review articles, however, will summarize previously conducted research throughout the entire paper. This is demonstrated throughout the entire article, not just in an Introduction section, which helps identify it as a review.]