How to Write a Bioscience Abstract

The limits and conventions above come from the PLOS guide to writing a journal abstract and the George Mason University Writing Center guide.

This guide explains how to write an abstract for a biology paper: finish the full paper first, then compress it into a standalone summary that follows the journal’s required length and headings: problem, methods, key findings and conclusions.

Authors still choosing where to submit can browse the bioscience journals collection before drafting. This guide then works through each abstract problem in turn, from limits to keywords.

Finding the word limit and format requirements

The journal author guidelines decide how long your abstract can be and how it is laid out, so read them before you write a word. PLOS advises authors to check the journal requirements first, such as required subheadings, and notes that most journals set a maximum word count.

When a journal gives no figure, general guidance offers a planning range. The George Mason University Writing Center describes an abstract as a paragraph of 150 to 250 words. It adds that an abstract for an IMRaD paper is typically one or two paragraphs, within a much wider range of 120 to 500 words. The width of that second range is the useful lesson: limits differ between publications, so no single number fits every submission.

• Symptom: the guidelines state a maximum. Treat it as a ceiling, not a target. A summary that is complete and clear below the ceiling is better than one stretched to fill it.
• Symptom: no limit appears on the page. Use the general range as a working figure and confirm the limit with the journal before you submit.
• Symptom: you are choosing between journals. Note each journal’s stated limit and heading requirements side by side. A draft that fits the strictest journal needs the least reworking if you are redirected.

What a bioscience abstract must contain

A bioscience abstract states the problem, the method, the findings and the conclusions, in that order. The George Mason University guidance says the abstract should begin with a brief but precise statement of the problem and then move through method, findings and conclusions.

The same guide suggests a rough allocation of space. About 25% goes to the purpose and importance of the research, about 25% to methods, about 35% to results and about 15% to implications. Results take the largest share and implications the smallest, so a draft in which background dominates is out of balance.

PLOS adds two refinements for the methods and results. It asks for key numeric data, including confidence intervals or p values, where possible. It also asks for important methods information without the low-level specifics. Each sentence maps to a section of the paper, so keep the structure of a bioscience research paper open beside your draft.

• Symptom: the abstract opens with a long background. Shrink the background until the methods and results hold their larger shares.
• Symptom: results are described in words only. Add the key numeric data that support each finding, with confidence intervals or p values where you have them.
• Symptom: the methods read like a protocol. Keep the design and main approach, and drop the low-level details that belong in the methods section.

Compressing the finished paper, sentence by sentence

Write the abstract after the full paper exists. The George Mason University Writing Center says you should draft your abstract after you have written a full draft of the paper. That way you summarise the results you actually report, not the ones you planned.

Then build the abstract in this order.

1. Background. Start with a brief introduction to the research area. PLOS suggests two or three sentences for this opening.
2. Question. State the research question you are trying to answer, plainly and in one sentence.
3. Methods. Name the study design and the main approach. Leave out anything a reader only needs when repeating the work.
4. Results. Lift your strongest findings from the results section, with their key numbers. If that section needs work first, see how to how to write results section of a scientific paper.
5. Conclusion. Say what the findings mean for the research area. Keep it to what the paper shows.

Highlight or copy the candidate sentences from the paper, then rewrite each as a shorter standalone sentence. Do not paste whole sentences from the body. They usually depend on context the abstract does not have.

Check the total against your limit only after all the sentences exist. If you are over, shorten the methods first, and leave the results and their numbers intact.

Structured or unstructured abstract

A structured abstract divides the summary under labelled headings. An unstructured abstract runs as continuous prose, often as the one or two paragraphs the George Mason guidance describes for IMRaD papers. The choice is rarely yours. PLOS notes that some journals may require a structured abstract with specific headings, so the author guidelines settle it.

The headings PLOS lists are Background, Objectives, Methods, Results and Conclusions. The Background section stays brief, in line with the two or three sentences above. PLOS also points authors to reporting guidelines matched to study design, such as CONSORT for randomized trials and STROBE for observational studies.

• Symptom: headings are required but your draft is prose. Split the draft along the heading boundaries and tighten each block so it stands alone under its label.
• Symptom: no headings are required. Keep the same order without the labels, so the abstract still moves from problem to conclusion.
• Symptom: you are reporting a trial or an observational study. Look at the reporting guideline for your design, since the journal may expect its elements to be visible in the summary.

Choosing keywords and helping literature databases find the abstract

Keywords are the terms that route readers to your paper from a search. PLOS asks authors to include keywords or phrases that help readers search for the work in indexing databases such as PubMed and Google Scholar. The George Mason guidance says the abstract should contain the most important key words referring to method and content, because these facilitate access to the abstract by computer search.

The practical choice is to pick terms that name both what you studied and how you studied it, then make sure those terms appear in the abstract text itself. A keyword list that repeats the title adds nothing to what a search already sees.

• Symptom: the keywords name only the topic. Add a term for the method so searchers who look by approach can also find the paper.
• Symptom: keywords never appear in the abstract. Revise the sentences so the main method and content terms are written out in the text.

Final read-through

Read the abstract as if it were the only part of the paper a reader will see. PLOS describes it as a concise, standalone piece with a clear message, so each claim must make sense without the body text.

• Symptom: the abstract promises rather than reports. The George Mason guidance advises against sentences that begin with phrases like “This essay will examine…”. State the finding instead.
• Symptom: the text is dense with abbreviations. PLOS advises avoiding abbreviations and acronyms unless they are absolutely necessary or widely known. Spell terms out where space allows.
• Symptom: the message is unclear. If a colleague who has not read the paper cannot say what you found, rewrite the results and conclusion sentences before polishing anything else.

Frequently asked questions