Anatomy of a Scientific Article
Scientific articles are research papers which describe one unique study designed to answer a particular question. The writer’s goal is to present the findings and convince the reader of a certain conclusion based upon their interpretation of the data. The articles are divided into sections, each with a particular purpose. The sections are: title, abstract, introduction, methods, results, discussion, and references. Literature reviews summarize many scientific articles on the same topic and do not generally follow the section format. Review articles provide a narrative overview of a particular disease state.
Title
The title provides key information about the research as well as where and by whom it was conducted. The names of the scientific contributors are customarily listed such that the scientist who performed most of the work is listed first and the senior scientist under whose supervision the work was conducted is listed last.
Abstract
The abstract summarizes the entire article in a short, concise paragraph generally devoting 2-3 sentences to each of theses sections: background, objective, study design, methods, results, and conclusions.
Introduction
The introduction prepares the reader for what will follow in the article and is the least structured of all the sections. The introduction generally opens with a discussion of the question that the study will answer, followed by a description of the current research on the topic, and closes with a statement of the purpose of the study.
Materials and Methods
The materials and methods section describes specifically how the study was performed. It should include enough detail so that another researcher can reproduce the study. It is essential that this section is accurate so that the discoveries may be validated or expanded upon by others. The methods section contains many subsections including: patient selection, study design, treatment(s), how the results were measured, and how the data were analyzed (the statistics).
- The patient selection section details how many and what type of patients were included in the study (age, gender, disease state(s), etc) and what type of patients were excluded from the study (certain ages, those that had other diseases, those on too many medications, etc).
- The study design section describes how the study was performed. Studies can be retrospective (a study of events that already have taken place) or prospective (a study that is designed before the study is started). This section will also describe if patients were randomized or not. Randomization assigns patients arbitrarily to treatment groups to avoid bias. Most studies should also be blinded to assure accurate results. Double blinded means that neither the patient nor the investigator know which group the patient is assigned to. Single blinded means the investigator knows which group the patient is assigned to, but the patient does not. Placebo-controlled studies compare a drug(s) treatment group to an untreated (placebo) group.
- The treatment(s) section defines each group that was compared in the study e.g., drug A versus drug B versus placebo, etc
- The next section should describe how the results were measured and should define what was the most important (primary) and lesser (secondary) endpoint studied. For example the primary endpoint may have been blood pressure and the secondary endpoints may have been cholesterol and growth rate.
- Finally, the statistics section describes how were the data analyzed, what type of statistical analysis was used.
Results
The results section presents the data collected during the study, there should be no conclusions drawn from the data in this section. This gives other scientists an opportunity to personally judge the merit of the data. Data are typically presented as tables, graphs, pictures, or schematic illustrations.
It is important to understand whether the data are presented as the mean (average), median (the number in the middle of a series of numbers; half the data values are above the median, and half are below), or mode (the number that occurs most frequently in a series of numbers). The presentation should also include a measure of how variable the results were. Variability is typically presented as the range, standard deviation, or standard error. The presentation of the results should also include a description of the significance of the data. There are 2 main types of significance; statistical significance and clinical significance. Statistical significance mathematically determines if the observed difference between two treatment groups is sufficiently large to be unlikely to have occurred by chance. Statistical significance is typically denoted by p values and/or confidence intervals.
Clinical significance implies that the treatment effect is enough to have a practical meaning to patients and/or health care providers. In some cases a result can be statistically significant, but have no practical importance. For example, a study may show that drug A statistically increased the life span of patients by 12 hours compared to drug B. However, those 12 hours have no real clinical significance.
Discussion
In this section authors present their interpretation of what the data represents. The discussion:
- Summarizes the results, and compares/contrasts the results to any available studies similar in nature
- Points out the limitations of the study, particularly those that may affect the conclusion
- Suggests future studies that may have arisen from this study
- Provides the author’s conclusion/interpretation of the study