IMRAD stands for Introduction, Methods, Results, and Discussion. It is the standard structure used to organize scientific research papers, and it has dominated academic publishing since the 1980s. If you’re writing a lab report, a thesis, or a journal article, you’ll almost certainly be expected to follow this format.
The International Committee of Medical Journal Editors describes IMRAD not as an arbitrary format but as “a reflection of the process of scientific discovery.” Each section mirrors a step in the research process: why you did the study, how you did it, what you found, and what it means.
How IMRAD Became the Standard
IMRAD wasn’t always the norm. A fifty-year survey of major medical journals found that no articles used the IMRAD structure in 1935, and only about 10% had adopted it by 1950. After World War II, international conferences on scientific publishing began recommending the format as a way to standardize how research findings were reported. By the late 1970s, the International Committee of Medical Journal Editors (then called the Vancouver Group) published formal guidelines endorsing it.
Adoption happened journal by journal. The New England Journal of Medicine fully adopted IMRAD in 1975, the British Medical Journal followed in 1980, and JAMA and The Lancet came on board by 1985. By the 1980s, IMRAD was the only structural pattern used in original research papers across these publications. Editors drove much of this shift, insisting on a clear, consistent format that would benefit readers and make peer review more efficient.
The Introduction: Setting Up the Problem
The Introduction answers three questions in sequence: What do we already know? What don’t we know? And how does this study aim to fill that gap?
This sequence is sometimes called the “funnel effect” because it starts broad and narrows. You open with background information on the topic, establishing what previous research has found. Then you identify a specific gap in that knowledge, something unanswered or unresolved. Finally, you state your research question, hypothesis, or purpose. A typical sentence at this transition point might read: “To address this gap in current knowledge, this study was designed to…” The entire section builds a logical case for why the study needed to happen.
The Introduction uses present tense when referring to established knowledge (“Previous studies show that…”) and past tense when describing what was done or found in prior work (“Smith et al. observed that…”).
The Methods: Explaining What You Did
The Methods section (sometimes called “Materials and Methods”) is a detailed account of how the study was conducted. Its purpose is reproducibility. Another researcher should be able to read this section and repeat the study. That means describing your study design, your participants or samples, any equipment or tools you used, and the steps you followed to collect and analyze data.
This section is written entirely in the simple past tense because you’re reporting actions already completed: “Participants were recruited from…” or “Samples were analyzed using…” It’s the most technical section of the paper, but clarity still matters. A reader should understand the logic of your approach even if they’re not an expert in your specific method.
The Results: Reporting What You Found
The Results section presents your findings, and only your findings. This is where you report the data, describe patterns, and note whether your results were statistically significant. Tables, figures, and graphs typically appear here or are referenced from this section.
The key discipline of the Results section is restraint. You report what happened without explaining why it happened or what it means. That interpretation belongs in the Discussion. Like the Methods section, Results is written in the simple past tense: “The treatment group showed a 15% improvement compared to controls.”
The Discussion: Interpreting the Meaning
The Discussion is where you step back and make sense of your results. It typically opens with a brief restatement of your key findings, then moves into comparing those findings with previously published research. Did your results align with what others have found, or did they differ? If they differed, why might that be?
This section also requires you to acknowledge the limitations of your study. If your sample size was small, if your method had a potential source of bias, or if your findings can’t be generalized beyond a specific population, you say so here. This isn’t a weakness; it’s expected. Every original paper could eventually be included in a meta-analysis or systematic review, so flagging limitations helps future researchers account for them.
Guidelines suggest the Discussion should not exceed the combined length of the Introduction, Methods, and Results sections. A common recommendation is six to seven paragraphs, organized into an introductory paragraph, several intermediate paragraphs covering interpretation and comparison, and a concluding paragraph. Verb tense shifts throughout: present tense for your own results, past tense for citing other studies, and occasionally future tense when suggesting directions for further investigation.
The Abstract: A Miniature IMRAD
Most research papers also include an abstract, which sits before the Introduction and serves as a condensed version of the entire paper. Structured abstracts mirror the IMRAD format directly, with labeled subsections for each part. The National Library of Medicine uses this structure in MEDLINE and PubMed citations, displaying each label in uppercase followed by a colon. When someone finds your paper in a database search, the abstract is usually all they see before deciding whether to read the full text.
Verb Tense Across Sections
One of the trickiest parts of writing in IMRAD format is switching verb tenses appropriately. Here’s how it breaks down:
- Introduction: Present tense for established knowledge, past tense for specific previous findings
- Methods: Simple past tense throughout
- Results: Simple past tense throughout
- Discussion: Present tense for your results, past tense for other research, future tense for suggested next steps
These conventions aren’t arbitrary. They signal to the reader whether you’re describing settled science, completed actions, or open questions, all without having to spell it out.
Where IMRAD Applies
IMRAD is the expected format for original research papers in the biomedical sciences, and it’s widely used across the natural and social sciences as well. Lab reports at the undergraduate level typically follow the same structure, sometimes labeled as “IMRaD” with the lowercase “a” reflecting the “and” in “Results and Discussion.” Some programs combine those last two sections into one, particularly for shorter reports.
Review articles, case reports, editorials, and theoretical papers generally don’t follow IMRAD because they aren’t reporting original experimental findings. The format is specifically designed for studies that follow the scientific method: pose a question, test it, report the data, interpret the outcome.