What is peer review?
Peer review is a process where research is evaluated by other experts in the field before being published. Well respected journals require primary research articles to go through the process of being reviewed, typically by more than one researcher. These peer reviewers may send the article back to the author(s) and ask them to conduct additional experiments before the research can be published.
When looking for research articles it is important to look for journals that require peer review. These articles are more reliable.
You might be asking, "But how do I can I make sure an article is peer reviewed?". You can go to the library's databases. Many of them will let you narrow your searches to only peer reviewed articles. See the example below. In the case of SciFinder you want to Click Refine and choose Document Type and Journal. As you may notice, you can also refine to reviews if you need to. Other databases have variants on this. If a database does not have this function you have two main options 1) check to see if on the about page of the database if it says it only contains peer-reviewed journals or 2) check the journal that the article is in to see if they only print peer-reviewed articles.
Here we will explore three types of articles: 1) a scientific research article (an example of a primary source) 2) a review article (an example of a secondary source) and 3) a general public article in a science magazine.
A scientific research article is an article, written by the scientists who did the research, on the results of their experiments and the implications for future research. These articles present information that helps the field move forward. The reason it is a primary resource is because it is original research done by the people directly involved in the work. These articles are peer reviewed. An example of this type of article is HERE. Notice that it has discrete sections to lead you through the work--an abstract, an introduction, an experimental (or methods) section, results, discussion, and conclusion. Figures are usually scattered throughout the paper. The language is usually technical. This organization is different than the organization found in review articles or science magazine articles. To learn more about strategies for reading scientific research articles, see the reading articles page.
A review article is an article that synthesizes the results of many scientific articles on a particular topic. This helps researchers to understand where the field currently stands. They normally summarize the state of the field, address lingering questions, and discuss next steps that might be taken in the field. For students new to the field these articles are an excellent way to be introduced to a topic and to provide further resources for study. Review articles are secondary sources because they report on the results and evaluate the results from primary sources. Some review articles are peer-reviewed. An example of this type of article is HERE. Notice that the sections of the paper are different than a scientific research article. Instead of detailing the experiment, the paper is organized around topics and subtopics. So there is an abstract, an introduction, topical sections, and then a conclusion (or sometimes also a discussion). The language is usually technical.
An article in a science magazine is different from both scientific research articles and review articles. The first two can be found in professional journals and are written by and directed at scientists. However, articles in a science magazine are directed at the general public and present information in an easily digestible form. They are not peer reviewed. They can be written by scientists or non-scientists. The language is not technical. These articles are usually either organized by topics or are written as one large piece. An example article is HERE.