Medical research articles tend to be structured in similar ways. This standard structure helps assure that research is reported with the information readers need to critically appraise the research process and results.
This guide to the structure of a biomedical research article was informed by the description of standard manuscript sections found in the International Committee of Medical Journal Editors (ICMJE) Recommendations chapter on Manuscript Preparation: Preparing for Submission.
If you are writing an article for submisson to a particular journal be sure to obtain that journal's instructions for authors for specific guidelines.
Example Article: Lyons EJ, Tate DF, Ward DS, Wang X. Energy intake and expenditure during sedentary screen time and motion-controlled video gaming. Am J Clin Nutr. 2012 Aug;96(2):234-9. doi: 10.3945/ajcn.111.028423. Epub 2012 Jul 3. PubMed PMID: 22760571; PubMed Central PMCID: PMC3396440. (Free full text available)
Article title: Should provide a succinct description of the purpose of the article using words that will help it be accurately retrieved by search engines.
Author information: Includes the author names and the institution(s) where each author was affiliated at the time the research was conducted. Full contact information is provided for the corresponding author.
Source(s) of support: Specific information about grant funding or source of equipment, drugs, etc. obtained to support the research.
Acknowledgments: This section may found at the end of the article and is used to name people who contributed to the paper, but not fully enough to be named as an author. It may also include more information about the authors' specific roles.
The structure of quantitative research articles is derived from the scientifc process and includes sections covering introduction, methods, results, and discussion (IMRaD). The actual labels for the various parts may vary between journals.
Abstract: A structured abstract reports a summary of each of the IMRaD sections. Enough information should be included to provide the purpose of the research; an outline of methods used; results with data; and conclusions that highlight the findings.
The introduction provides background information about what is known from previous related research, citing the relevant studies, and points out the gap in previous research that is being addressed by the new study. Often, many of the references cited in a paper are in the introduction. The purpose of the research should be clearly stated in this section.
The sample paper's introduction links television watching to increased energy intake and obesity, notes that several studies have shown a similar link with video gaming, and states no study was identified that compared television and video gaming. Eighteen of the thirty-one references used in the paper are cited in the introduction. The final paragraph of the introduction has two sentences that clearly state the purpose and the hypothesized expected outcome of the study.
The methods section clearly explains how the study was conducted. The ICMJE recommends that this section include information about how participants were selected, detailed demographics about who the participants were, and explanations of why any particular populations were included or excluded from the study. The details of how the study was conducted should be described with enough detail that the study could be replicated. Selected statistical methods should be reported in enough detail that readers can evaluate their appropriateness to the data being gathered.
The sample paper’s methods section includes subsections covering: recruitment; procedures used for each study subgroup (TV, VG, motion-controlled VG); what snacks and beverages were used and how they were made available; how energy intake and energy expenditure were measured; how the data was analyzed and the specific statistical analysis and secondary analysis that was used.
The results section reports the data gathered and the statistical analysis of the data. Tables and / or graphs are often used to clearly and compactly present the data.
The results section of the sample paper has two subsections and two tables. One subsection and related table shows the analysis of participant characteristics, The other subsection and table covers the analysis of energy intake, expenditure, and surplus.
In order to critically appraise the quality of the study you need to be able to understand the statistical analysis of the data. Two articles that help with this task are:
Another aid to critically reading a paper is to see if it has been included and evaluated in a systematic review. Try searching for the article you are reading in Google Scholar and seeing if the cited references include a systematic review. The sample paper was critically reviewed in:
The discussion section clearly states the primary findings of the study, poses explanations for the findings and any conclusions that can be drawn from them. It may also include the author’s assessment of limitations in the research as conducted and suggestions for further research that is needed.
The structure of biomedical research articles has been standardized across different journals at least in part due to the work of the International Committee of Medical Journal Editors. This group first published the Uniform Requirements for Manuscripts Submitted to Biomedical Journals in 1978.
The Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly work in Medical Journals (2013) is the most recent update of ICMJE's work.