Research Resource Center

Type of research papers

There are many types of research papers that can be seen in medical journals, each one of these types serves a distinct purpose. With different types of papers, different criteria are used by medical journals to evaluate the manuscripts in the process of making the decision whether to accept or reject a manuscript. Nevertheless, each type of those types has the same basic structure, which can be summarized by the acronym IMRAD (Introduction, Methods, Results, Discussion)

The different parts of a research paper

The types of published papers are dependent on the editorial policy and the mission of the individual journals, and these types include:

Types of research articles

Original articles:

These are the standard scientific articles, which usually include a description of how the research was done and what the results mean. Original articles or primary research articles report the findings of scientific work, and most often are published in peer-reviewed journals. This is the most important type of articles because it provides new information based on original research. Original Articles should consist of the following headings: abstract, introduction, methods, results and discussion (IMRAD).

Review articles:

They are also published in peer reviewed journals. However, these differ from original articles in that they are not based on original research. Review articles usually lack a “Methods and materials” section. It is a detailed analysis of recent updates on a specific topic, and highlights the important points that have been previously reported in the literature. This type of articles does not deliver new information and does not show the opinion of the author. Review articles organize, clarify, and summarize existing work on a certain scientific topic and provide comprehensive citations to the full spectrum of relevant literature.

Case report:

It is usually short and focused. Case reports are usually peer-reviewed and can be an important part of the medical literature. This report is a description of a single case with unique features such as a previously unreported observation of a known disease, the unique use of imaging or diagnostic tests to reveal a disease, an unreported clinical condition, an unreported treatment of a recognized disease or an unreported complication of a procedure.


In most cases, it is a short review or critique of an original article accepted for publication or a brief description of a subject that does not warrant a full review. It may be also a tool to draw attention to very recent innovations or subjects of general interest to readers. It is usually written by the journal’s editor, and it express the author’s view about a particular issue that may be of scientific policy or urging a particular research agenda or even taking a side in a particular scientific dispute. These articles can be well researched and include a lot of citations to the peer-reviewed literature, or simple items without citations.

Pictorial essay:

This is a teaching article that relies on the quality of its images, and the text is usually limited with much of the message contained in the figure legends. This type of articles allows a large number of figures but a limited number of references.

Commentary (some consider it close to Editorial):

It is a short article that describes an author’s personal experience in a specific topic, and it does not provide new information and should outline the various viewpoints that exist.

Technical note:

It is a description of a specific technique or procedure, a modification of an existing technique, or a new equipment applicable to a branch of medicine. It is more limited in scope and length compared to a research paper; however, it undergoes full peer review.

Letter to the editor:

It is usually short and can be written on any subject of interest to the journal readership including comments on previously published articles. Authors of the published articles are invited to make a written response, which may sometimes be used for floating new hypotheses and to draw readers’ attention to important points.

Other types of papers:

There are many other types of papers. These types vary according to the mission and the style of journals. These types include historical articles, short communications, evidence-based practice, health policy and practices, experimental studies, and information technology. Conference proceedings, comments, and pre-prints/post-prints can also be included in this category

Gray literature:

This term largely refers to items that are distributed or published outside of the traditional journal and book publisher, however it is very important not to miss this type of papers because it can contain valuable information and can be included in systematic reviews.


These are the final products from research conducted for a PhD or a master degree, and they are often very long, going into great details about methods with lots of appendices of data. While they undergo exhaustive review by academic advisers and committee members, they are not considered truly peer-reviewed.

Main types of research papers



Content created by Alaa AlHaffar, MD

Content reviewed by Mariana Haydar, MD

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