How to write an abstract

By Dr. Rafiq Muhammad, MD, PhD · Updated June 2026

The abstract is the most-read and least-revised part of most papers — a mistake, because for many readers it’s the only part they read, and it’s what an editor scans first. A good one miniaturises the whole paper in four moves and about 150–300 words. Write it last, when you actually know your results.

The four moves

1. Background / aim. Why the study matters and the question it asked — one or two sentences.
2. Methods. What you did — design, sample, and approach, briefly.
3. Results. The main findings — ideally with the key numbers, not just “significant differences were found.”
4. Conclusion. What it means and why it matters — the single takeaway.

That’s a compression of IMRaD: each move maps to a section of the paper. If a move is missing, the reader can’t judge the work.

Structured vs unstructured

A structured abstract uses labelled headings (Background, Methods, Results, Conclusions) and is standard in clinical and health journals. An unstructured abstract makes the same four moves as one flowing paragraph, common across the sciences and humanities. The journal’s instructions for authors decide which — check before you draft.

The rules that catch people out

• It must stand alone. No citations, no undefined abbreviations, nothing that isn’t in the paper.
• Respect the word limit — usually 150–300 words; conferences are often shorter.
• Put numbers in the results move — specifics earn trust; vague claims don’t.
• Match the paper. Because you wrote it last, it should agree with your final aims and conclusion exactly.