Scientific journal articles are typically peer-reviewed by other experts in the field to determine if:

• Methods are valid for answering the research question
• Conclusions are backed up by results
• Limitations of the study are acknowledged
• Research findings are described clearly and completely
• The topic of the article fits within the scope of the journal

To find out whether the journal that an article is published in is peer-reviewed, search for the Journal Title, Abbreviation, or ISSN in Ulrich's Web.

If the black book symbol appears next to the journal title in your search results, that means that the journal is peer-reviewed.

Just because a journal is peer-reviewed, that doesn't mean that all articles it contains are!

• Primary research studies and review articles are typically peer-reviewed.
• Editorials and Letters to the Editor may not be peer-reviewed.

Peer-review is an important part of the scientific process, but it is not perfect! You should still critically evaluate peer-reviewed journal articles.

Reading, analyzing, synthesizing, and building upon the scientific literature is an important part of conducting original research. To help you ensure that the literature you are using to support your research is trustworthy and based upon strong scientific evidence, ask yourself the six questions below:

How did you find the source?

You may need to be more (or less) critical of an information source, depending on how you discovered it.

• Recommended by your supervisor, lab mate, instructor, or another trusted source?
• Found in a library database containing a curated collection of scientific literature?
• Found in the citation list of an important article in the field? If so, what does the citing article say about it?
• Found on Google, Google Scholar or another source with broad or unknown criteria for what is included?

Who wrote the source?

• What qualifications and expertise do the authors have?
• What is their reputation in the field?
• Did the author(s) collect original research data, or are they citing another researcher's data? Trace the data back to the original source to make sure you understand the collection methods and conditions.

When was the source published and/or modified?

• Does the topic you are studying require the most up-to-date information?
• Is it possible that new discoveries may have changed our understanding?
• Has the article been retracted? Even respected researchers and peer-reviewers make mistakes! Visit Retraction Watch for updates on recently retracted papers or to find out if a paper you are interested in has been retracted.
• If it is a conference proceeding or preprint, has an in-depth, peer-reviewed research article been published yet?

What data, methods, and conclusions does the source contain?

• Are the data, study design, and research methods relevant to your own work?
• Are the methods appropriate for answering the research question?
• Do the findings support the researchers' claims?
• Do you agree with the authors' interpretation of their data?
• Do the findings agree with other reliable sources?

Where was the source published?

• Is the journal and/or publisher respected in the field? For example, journals published by respected professional associations like the American Chemical Society (ACS) and the Royal Society of Chemistry (RSC), typically have robust quality controls and review processes.
• Is the journal peer-reviewed? More information about how to
• Use U of T's Identifying Predatory Publishers Checklist to watch out for common characteristics of deceptive publishers (also known as "predatory journals"): for-profit entities that purport to publish high quality academic research, but do not follow accepted scholarly publishing best practices.

Why was the source published?

Most of the sources you use and cite in your research should be scholarly, which means that they are written by experts for an academic audience. There are multiple types of scholarly sources, which are useful for different purposes:

• Books: Scholarly books usually published by academic publishers (i.e. Elsevier, Wiley, ACS) or university presses, with the goal of summarizing or compiling results of scientific research to give an overview of a broad topic. Books take a long time to develop, so they may not always contain the most current information. Great for when you are new to a topic!
• Review Articles: Compile and/or synthesize primary research on a topic to draw larger conclusions or demonstrate how research has developed over time. Review articles usually have a narrower scope than books do, and can point you to important papers, researchers, breakthroughs or shifts in thinking around a particular topic.
• Primary Research Articles: Communicate the results of original research studies. In chemistry, these include Communications or Letters, which are short, peer-reviewed articles that aim to quickly share brief descriptions of new experimental or theoretical findings. There are whole journals dedicated to this type of article. (ex. Environmental Science & Technology Letters).
• Preprints: Found on sites like arXiv.org and ChemRxiv.org, preprints allow authors to make primary research articles available before peer-review and publication. Why? While the peer-review process is an important part of scientific publishing, it takes time and researchers may want to get their work out there more quickly. Preprints are NOT PEER-REVIEWED, and are therefore less reliable than published studies. You should always try to find, read, and cite the published version of the article, if one exists.
• Conference proceedings: Communicate new discoveries, work in-progress, and/or preliminary findings. Conference proceedings are NOT PEER-REVIEWED and should not be taken as conclusive or established evidence. They may or may not be followed by a published research article.