Environmental Sciences: Understanding Peer Review

Peer review is a term that you will be encountering often (assuming you aren't already familiar with it). It's a specific and rigorous process that is applied across all types of disciplines as a way to ensure the credibility and accuracy of published research. Most research articles published in academic journals undergo peer review, as do many books and book chapters published by and for academics. Peer-reviewed publications are typically considered the gold standard of scientific information, and are often the only types of sources that professors will allow students to cite in their papers (especially in the first few years of college).

So what does the peer review process entail, and why is it so respected?

The process generally follows these steps:

1. The author of a manuscript decides to submit it to a journal. Most journals require submissions to be anonymized, meaning the manuscript cannot have any information that clearly identifies the author.
2. The editor of the journal reviews the manuscript. If the editor determines that the paper does not fall within the stated scope or purpose of the journal, they may reject the paper outright. Typically if this happens, the editor will notify the author of the reason for the rejection, and may make some recommendations for journals that might be a better fit for the manuscript.
3. If the editor instead determines that the topic of the paper falls within the scope of the journal, they will send the anonymized manuscript to two or more researchers in the same field who will then review the article. The identities of these reviewers are most often kept secret from the author, which is called blind peer review (often double-blind, since the author is also typically not known to the reviewers). Blind reviews are intended to remove as much bias as possible from the process.
4. The reviewers will read through the manuscript and check for several things. Does the introduction properly contextualize the research in the existing scientific literature? Is it missing any key citations that may provide more information or possibly even refute the claims in the paper? Are the methods described in the manuscript appropriate for answering the research question? Are the statistical analyses appropriate and correctly interpreted? Are the conclusions of the paper supported by the results and discussion? Does the paper make an important contribution to the scientific literature? The reviewers will answer these questions and discuss anything else they think to be relevant, and will submit a written review back to the journal editor. This review will also include a recommendation to either reject the paper due to major flaws or other issues, or accept the paper for publication (often with recommended revisions for the author to make before the paper will be ready to publish).
5. The editor will read the submitted reviews to see if the reviewers make the same recommendation to publish or reject, and if so, will typically follow their recommendation. If the reviewers do not agree, the final decision rests with the editor. Either way, the anonymous reviews are sent back to the author so they can have the feedback. If revisions are needed, the author will have a chance to make them before the paper is finally accepted for publication.

The key part of the review process is that the paper is reviewed by other researchers in the same field (i.e., the author's peers). Researchers outside the field of the manuscript are far less likely to be able to adequately review a topic with which they are less familiar. For example, you would not expect an astrophysicist to be a reviewer for a manuscript on molecular biology. That's not their field, they will not be familiar with the breadth of the scientific literature in that area, and they likely haven't been trained in the different methodologies used in that field.

As mentioned above, most articles in academic journals undergo peer review and revision prior to publication. However, not all of these articles fulfill the same purpose. There are two main types of peer-reviewed articles you will encounter.

Primary Research

Most papers you read (and many that you will write) will follow the structure and format of original (i.e., primary) research. An article like this will contextualize and describe an experiment that was conducted by the author(s), and will report and discuss the results of that experiment. The headings and layout of these types of papers typically follow what is called the IMRaD format: Introduction, Methods, Results, and Discussion. 

Primary research comprises the bulk of the scientific literature, and it is what most professors will ask you to find and cite when you write papers.

Example

• Scott, E., Holden-Dye, L., O'Connor, V., & Wand, M. E. (2020). Intra strain variation of the effects of gram-negative ESKAPE pathogens on intestinal colonization, host viability, and host response in the model organism Caenorhabditis elegans. Frontiers in Microbiology, 10, 3113. https://doi.org/10.3389/fmicb.2019.03113

This article is a great example of primary research. Notice the main section headings follow the IMRaD format. There are additional subheadings that go into more detail about the research being reported, but the big ones are exactly what we would expect to see.

Secondary Research

There also exists secondary research, which synthesizes original research pertaining to a specified topic and places the results and conclusions of these papers in context with each other. Secondary research does not report on any experiments conducted by the authors, but instead discusses the experiments of others. The headings and layout of secondary research is much more variable, as the authors may decide to organize the information however best makes sense.

These articles are often called review articles or review papers, as they are essentially giant literature reviews. They can be extremely useful for gathering background knowledge on a particular topic, as the authors tend to collect and cite as many primary research articles as they can find for that topic. If you are able to locate a review article that discusses a topic you are writing about, make sure you take a look at the references for that paper, as it's highly likely many of them will be useful for you to read and cite in your own paper.

Be careful though! If you find a review article that cites primary research relevant to your paper, don't cite the review article! You always want to track down the original paper with the original claim. For one, it gives proper credit to the author(s) of the original paper; for another, it serves as a way to verify that the author of the review paper correctly interpreted the information they are citing. 

Example

• Wang, G., Zhao, G., Chao, X., Xie, L., & Wang, H. (2020). The characteristic of virulence, biofilm and antibiotic resistance of Klebsiella pneumoniae. International Journal of Environmental Research and Public Health, 17(17), 6278. https://doi.org/10.3390/ijerph17176278

This article is a great example of secondary research. The overall layout of the paper does not follow the IMRaD format, and is instead dependent on the overall themes the authors found while reading through all the primary research they cited.

Some shared headings

You may have noticed that both of the example articles had a few common elements: the abstract, introduction, conclusion, and references. These sections are pretty standard no matter the type of article you're writing, so it's important to look past the first page in order to determine whether an article is primary or secondary research, as well as the overall goal of the research. Is it reporting on an experiment or analysis conducted by the author(s)? Then it's primary research. Is it only synthesizing other research? It's secondary research.

Beware the systematic review

You may run across some articles in your research that are titled or described as systematic reviews, systematized reviews, scoping reviews, or something similar, but which follow the IMRaD heading structure. These are still considered secondary research, even though they are structured like primary research.

If the Methods section of a paper describes a literature search but no other methodology, you are almost certainly looking at secondary research.