Journal Articles

Original Research Article

An original research article is the cornerstone of scientific publishing. It reports new empirical findings from a study designed to answer a specific research question or test a hypothesis, involving original data collection and analysis whether from experiments, clinical trials, observational studies, or surveys. What sets it apart is its commitment to rigorous, reproducible methodology, making it one of the higher forms of evidence in the research hierarchy.

Most original research articles follow the IMRD structure: Introduction, Methods, Results, and Discussion. This mirrors the scientific method itself. The Introduction sets the scene by explaining the rationale and identifying the gap in knowledge. The Methods section describes exactly how the study was conducted, in enough detail for another researcher to replicate it. The Results present findings objectively without interpretation, while the Discussion contextualises those findings within the broader literature, acknowledges limitations, and draws conclusions.

Systematic Review

A systematic review sits at the top of the evidence hierarchy. It answers a specific, focused research question by using explicit and reproducible methods to identify, appraise, and synthesise all relevant evidence on a topic. Its defining strength is the rigorous process used to minimise bias, including predefined eligibility criteria, comprehensive database searches, duplicate screening, and formal risk-of-bias assessment.

A systematic review may or may not include a meta-analysis. When the included studies are sufficiently similar in design and outcome measures, their numerical results can be statistically pooled into a single overall effect estimate. This is the meta-analysis. However, when such pooling is not appropriate, the review presents a structured narrative synthesis instead. Importantly, a systematic review without a meta-analysis is still a systematic review. It should not be confused with a narrative review, which differs fundamentally in its methodology.

Narrative Review

A narrative review provides a broad overview and interpretation of the literature on a topic. Unlike a systematic review, it does not follow a strict predefined protocol or exhaustive search strategy. Instead, it draws on the author’s expertise and judgement to select, synthesise, and critically interpret relevant literature, making it more flexible and discursive in nature.

This flexibility is both its strength and its limitation. A narrative review can cover broader or multiple questions, incorporate historical context, and reflect evolving themes in a field,  qualities that make it well suited to hypothesis generation or providing background context. However, because study selection is not governed by strict criteria, it is more susceptible to selection bias than a systematic review.

A good narrative review should nonetheless be transparent about its search process, synthesise rather than merely list studies, and critically analyse the strengths and weaknesses of the evidence.

Case Report

A case report describes the clinical course, diagnosis, treatment, and outcome of an individual patient or a small series of patients. Its value lies in documenting unusual, rare, or instructive clinical observations that could not be captured through larger studies — making it particularly useful for signalling rare events, highlighting unexpected outcomes, or generating new hypotheses.

Case reports follow a narrative structure and should adhere to the CARE (CAse REport) guidelines for completeness and transparency. The case presentation should be organised chronologically, covering patient information, clinical findings, diagnostic assessment, therapeutic intervention, and follow-up outcomes. The discussion then contextualises the case within the existing literature and draws out the key learning points.

Two important considerations for trainees are patient confidentiality and informed consent. All identifying information must be removed, and written patient consent must be obtained and documented before submission, as most journals require it.

Letter to the Editor

A letter to the editor is a short, focused response to an article recently published in the same journal. It serves as a form of post-publication peer review, allowing readers to raise critical comments, point out methodological concerns, offer additional data, or provide an alternative interpretation. Most journals expect letters to be submitted within three to six months of the original article’s publication.

The format is simple and direct, beginning with a clear reference to the original article, followed by a concise and evidence-based argument, and closing with a brief summary of the implication or suggestion. There is no abstract, and figures or tables are rarely permitted. The tone must remain polite and academic throughout, even when the comments are critical.

Opinion Piece

An opinion piece is variously called a viewpoint, perspective, commentary, or editorial depending on the journal. It offers the author’s expert interpretation or argument on a topic of broad relevance to the field. Unlike a letter to the editor, it does not need to respond to a specific published article. Instead, it may address policy implications, emerging controversies, ethical issues, or future research directions, with the aim of stimulating discussion and provoking thought among readers.

While opinion pieces allow more creative latitude than research articles, they must remain evidence-informed and well-reasoned. The argument should be clear and stated early, developed logically through the body of the article, and supported by selective but relevant references. Counterpoints should be acknowledged to demonstrate balance and intellectual honesty. A strong, forward-looking conclusion is particularly important in this format.