Reading the biomedical research literature can be a time-consuming and intimidating task, especially when you need to find specific information in a hurry. Where do you start? How do you find what you need? Like everything else in science, there is a reason why scientific articles are organized the way they are. With the exception of a few other formats, biomedical articles are written using the “IMRaD” format: introduction (I), Methods (M), Results and Discussion (RaD). The IMRAD format first appeared in the 1940’s and became the standard for medical research articles by the 1950’s. In the 1970’s, The International Committee of Medical Journal Editors released the Uniform Requirements for Manuscripts Submitted to Biomedical Journals (ICMJE website) which established the standards for preparing and formatting manuscripts submitted for publication. Today, IMRaD dominates scientific writing with almost all scientific research journals using this basic structure.
The standard is intended to guide authors to include specific information that addresses essential questions of their hypothesis. This is the “who, what, where, when and why” of the scientific research study. However, IMRaD also facilitates reviewing and finding information in an article. The figure below is a diagram of the basic IMRaD structure updated to reflect additional sections commonly used today (Wu 2011).
Notice the overall “wineglass” silhouette as well as the various shapes of each section. These demonstrate the viewpoint in the development of the story. The size, width and opposing orientation of the trapezoids represent that a hypothesis is derived from a broad perspective (Introduction) that tapers down to a specific question(s), narrowed to focus during experimentation (Methods and Results) followed once again by a wide trapezoid (Discussion and Conclusions) where the implications of the work are explored and expanded upon. How does this help? Each section of the article answers specific questions (indicated by arrows) and guides you to find specific information or details related to what you are looking for. For example, let’s say you are trying to find an antibody. Obviously, you would scan the methods section. However, if you want to know the antibody sub-cellular localization, this will be found in the results section along with images and frequency distribution of the marker in different pathological entities. If you want to know why author(s) chose to test this specific antibody, then look in the introduction to find a description of why there is a problem and why it is important. The introduction is also where current literature addressing the problem is reviewed.
Literature citations are used throughout the manuscript to provide background and either support or refute the hypothesis. The citations refer to specific research articles (listed in References section), that help develop a better understanding of the origins of the topic and find additional details about the problem. Backward reference searching (a.k.a. reverse searching) was the mainstay of literature searches before the advent of digital literature repositories such as PubMed or Google Scholar. By reviewing the references, older literature cited can be quickly collected. Even with digital resources, reverse searches are still a very effective way to collect references and background information. The Discussion section will contain a summary of the diagnostic and prognostic implications of the marker. Including what the results mean for treatment of a disease entity as well as any flaws or limitations in the current study to provide direction for future research.
You will note that the Abstract also has a wineglass inserted into its box and contains a brief summary or synopsis of the entire article. Abstracts are important because this is often the first section used to screen articles (besides the title). A complete abstract, as shown in digital literature repositories, is limited in terms of space with as few as 250 words. Overall, authors use a condensed IMRaD with 25% of the abstract space for an initial introduction, 25% for methods, 35% for results and 15% for the discussion. To facilitate screening without reading the entire article, the abstract can be scanned to see if it is relevant to the question and/or information you are trying to find. Finally, the Title (small circle) is extremely important. The title must be brief and informative enough for a person to be able to scan and get a reasonable idea of article content but also be readily searchable in digital repositories. Key Words are important to be searchable, and often found in the title and under the abstract.
In the second post in this series, Cruising the Biomedical Scientific Literature: Where to search? to learn about the most popular literature search engines, PubMed and Google Scholar, how they work and use them to search for articles.
International Committee of Medical Journal Editors (ICMJE) found at http://www.icmje.org/recommendations/browse/manuscript-preparation/preparing-for-submission.html#2021#Blog#GeneralAnatomicPathology
Wu, J. (2011). "Improving the writing of research papers: IMRAD and beyond." Landscape Ecology 26: 1345-1349. DOI 10.1007/s10980-011-9674-3
Written by: Luis Chiriboga, PhD, HT(ASCP), QIHC