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Academic Writing

How to Write an Abstract for a Paper, Thesis, or Journal

An abstract is a standalone summary that lets a reader decide whether the full paper is worth opening. The UNC Writing Center calls it a self-contained, short, and powerful statement that describes a larger work — not a review, and not a paragraph copied from the introduction or the conclusion. This page is that writing how-to. It is not how to write a research paper, which covers the whole draft, and not how to write a research proposal, which sells unwritten work.

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Photo: Alexa Mazzarello, Wikimedia Commons (CC0)
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Quick Answer: How to Write an Abstract

Write the paper first, then compress it. University of Toronto Writing Advice says an informative abstract answers four questions in about 100–250 words: why you did the work, what you did and how, what you found, and what those findings mean. Purdue OWL treats that same job as a condensed IMRaD: one or two sentences per major section, usually about 150–200 words, or 50–75 words when a conference program is the venue. IEEE Author Center tells authors to write the abstract last and edit it until it matches the finished article. Summarize the paper you actually wrote. If you need a starter sentence, use a labelled template — not a fabricated study.

Starting templates (fill from the paper you wrote; do not invent results)

Informative / IMRaD paper:

[Problem or gap in one sentence]. This study [design, sample or materials, and analysis]. Results showed [the main finding with a number, effect, or comparison the paper actually reports]. These findings [the implication the Discussion earned], with the main limit that [the constraint that changes interpretation].

Humanities / argument paper:

This [essay / article / dissertation] examines [object or corpus] in order to argue that [the claim]. Drawing on [kinds of evidence], it shows that [the main reading]. The contribution is [what changes in the scholarly conversation], not a plot summary of the text.

Descriptive abstract (scope only):

This paper describes [the topic, the sources or method, and the sections covered]. It does not report results. Use this shape only when the assignment or journal asks for a descriptive abstract of about 100 words.

Structured medical / trial abstract (copy the journal's headings):

Background. [context]. Objective. [purpose]. Methods. [participants, setting, interventions, primary outcome, allocation, blinding]. Results. [n per group; primary-outcome effect with precision; important harms]. Conclusions. [principal claim without overinterpretation]. Trial registration. [registry and number]. Put funding where the journal asks — CONSORT 2025 lists it in the abstract; ICMJE lists it after the abstract.

Nature-style summary paragraph (only if that journal asked for it):

[2–3 sentences that introduce the field to a scientist outside it]. [Background and the specific unsolved problem]. Here we show [the main conclusion]. [2–3 sentences that say what that result changes in the field]. Nature wants this paragraph referenced and usually free of numbers and abbreviations; IEEE wants the opposite — no numbered citations.

APA 7 professional format (not required for most student papers):

Page 2. Centered bold heading Abstract. One unindented paragraph, at most 250 words. Next line, indented: Keywords: term one, term two, term three

Use the thesis-statement generator only to tighten the claim you are summarizing. Then format the sources the paper actually cites with the CitationEasy generator.

What an Abstract Is For — Official Definitions

Four authorities describe the same job. UNC names the genre. Toronto names the four questions a useful abstract answers. Purdue OWL names the default length and the conference-program exception. APA Style's Abstract and Keywords Guide (7th ed., citing Publication Manual §§2.9–2.10) names the 250-word cap and the student-paper exception. None of them treat the abstract as a teaser that hides the results.

UNC Writing Center, “Abstracts”

An abstract is a self-contained, short, and powerful statement that describes a larger work.
An abstract is not a review, nor does it evaluate the work being abstracted. While it contains key words found in the larger work, the abstract is an original document rather than an excerpted passage.
Abstracts allow readers who may be interested in a longer work to quickly decide whether it is worth their time to read it. Also, many online databases use abstracts to index larger works. Therefore, abstracts should contain keywords and phrases that allow for easy searching.

University of Toronto Writing Advice, “The Abstract” (Margaret Procter)

Typically, an informative abstract answers these questions in about 100-250 words:
Why did you do this study or project?
What did you do, and how?
What did you find?
What do your findings mean?
An abstract will nearly always be read along with the title, so do not repeat or rephrase the title. It will likely be read without the rest of the document, however, so make it complete enough to stand on its own.
Do not refer in the abstract to information that is not in the document.
Avoid using I or we, but choose active verbs instead of passive when possible (the study tested rather than it was tested by the study).

Purdue OWL, “Abstracts” (Graduate Writing Genres)

While the application may necessarily change the length of the abstract (a conference program may only allow for 50-75 words, for instance), the purpose and structure remains fairly constant.
Abstracts are generally kept brief (approximately 150-200 words).
A reliable strategy is to write the abstract as a condensed version of your article, with 1-2 sentences summarizing each major section.

APA Style Abstract and Keywords Guide (7th ed.), citing Publication Manual §§2.9–2.10

Abstracts and keywords are not typically required for student papers. Students should consult their instructor or institution to determine whether to include an abstract and/or keywords.
The abstract needs to provide a brief but comprehensive summary of the contents of your paper. It provides an overview of the paper and helps readers decide whether to read the full text. Limit your abstract to 250 words.

The abstract addresses the following (usually 1–2 sentences per topic):

  • key aspects of the literature review
  • problem under investigation or research question(s)
  • clearly stated hypothesis or hypotheses
  • methods used (including brief descriptions of the study design, sample, and sample size)
  • study results
  • implications (i.e., why this study is important, applications of the results or findings)
Keywords need to be descriptive and capture the most important aspects of your paper. They are used for indexing in databases and as search terms for readers. Include three to five words, phrases, or acronyms as keywords.

Descriptive vs Informative Abstracts

UNC distinguishes two common types. A descriptive abstract maps the topics. An informative abstract also reports results and conclusions and can stand in for the paper when a reader is deciding whether to download it. A rarely used third type, the critical abstract, evaluates the work; UNC sends that job to the literature-review handout. If you are unsure which type to write, ask the instructor or read abstracts in the target journal.

UNC Writing Center on the two types

A descriptive abstract indicates the type of information found in the work. It makes no judgments about the work, nor does it provide results or conclusions of the research.
Descriptive abstracts are usually very short—100 words or less.
A good informative abstract acts as a surrogate for the work itself. That is, the writer presents and explains all the main arguments and the important results and evidence in the complete article/paper/book.
You can also make a guess based on the length allowed; i.e., 100-120 words = descriptive; 250+ words = informative.

UNC demonstrates both types on its own abstracts handout. Those two sentences are official examples, not a study to copy into an unrelated paper.

UNC’s worked pair (this handout on abstracts)

Descriptive:

The two most common abstract types—descriptive and informative—are described and examples of each are provided.

Informative:

Abstracts present the essential elements of a longer work in a short and powerful statement. The purpose of an abstract is to provide prospective readers the opportunity to judge the relevance of the longer work to their projects. Abstracts also include the key terms found in the longer work and the purpose and methods of the research. Authors abstract various longer works, including book proposals, dissertations, and online journal articles. There are two main types of abstracts: descriptive and informative. A descriptive abstract briefly describes the longer work, while an informative abstract presents all the main arguments and important results. This handout provides examples of various types of abstracts and instructions on how to construct one.

Use a descriptive abstract when

  • The assignment or journal asks for scope only
  • The work is a humanities overview that should not preview the reading
  • The word limit is about 100–120 words (UNC's length guess)
  • You can name topics and methods but not results

Use an informative abstract when

  • Readers will search a database and decide from the paragraph alone
  • The paper reports methods and findings (science, social science, engineering, medicine)
  • APA, IEEE, ICMJE, or the journal wants a comprehensive summary
  • You can state results without sending the reader to a table

When You Need an Abstract (and When You Do Not)

The biggest student error is adding an abstract that the assignment never asked for — or omitting the one a journal requires. APA 7 §2.9 is explicit that student papers usually skip the abstract. IEEE is explicit that every published article has one. ICMJE is explicit that original research, systematic reviews, and meta-analyses need a structured abstract. Purdue OWL is explicit that a conference program may want 50–75 words, not a 250-word journal capsule.

  • Most APA student papers: no abstract unless the instructor asks. If one is required, follow the professional format in the Abstract and Keywords Guide.
  • IEEE journal and conference papers: required. The IEEE Editorial Style Manual for Authors says the abstract must be one paragraph and 150 to 250 words. The Author Center page says “up to 250 words.” Use the venue's instructions if they disagree.
  • Medical and many health journals: structured abstract for original research, reviews, and meta-analyses (ICMJE Recommendations, January 2026). Trial abstracts also need the CONSORT 2025 item 1b list.
  • Nature research Articles: a fully referenced summary paragraph of about 200 words, written for readers outside the discipline (Nature formatting guide). That is not an IEEE-style unreferenced capsule.
  • Theses and dissertations: required at most graduate schools. University of Toronto SGS caps a doctoral abstract at 350 words and a master's abstract at 150 words, double-spaced, with no graphs or tables. The title, degree, year, name, department, and university sit above the paragraph and are not in that count. Your graduate office, not this page, is the word-count authority.
  • Conference proposals, grant applications, and book proposals: UNC lists these as common abstract occasions. Follow that call's heading list and limit. A 60-word program blurb is not a journal abstract.
  • MLA course essays and most short humanities papers: no abstract unless the prompt asks. Do not paste a science abstract onto a close-reading paper.

APA 7 Format: Page, Paragraph, and Keywords

When an abstract is required, APA Style puts it on page 2, under the bold centered heading Abstract. The paragraph is not indented. Keywords sit on the next line. The official guide's format rules are mechanical; breaking them is how an otherwise good summary fails a checklist. This is also where this page parts from how to format academic papers, which covers the rest of the student manuscript.

APA Style Abstract and Keywords Guide — format facts

  • Placement: second page of the paper
  • Section label Abstract: centered and bold, first line of the page
  • Text: one line below the label, not indented, single paragraph, double-spaced
  • Length: 250 words unless the instructor or journal sets another limit
  • Keywords label: indented, italic, not bold — Keywords:
  • Keyword text: same line, one space after the label; lowercase except proper nouns; commas and spaces; no period after the last term; any order, not necessarily alphabetical
  • If keywords wrap, double-space and do not indent the second line

The keyword line is not a second thesis. APA wants three to five terms that name the topic, population, method, or application. UNC's breakdown of the Andrews dissertation uses searchable terms such as social movements and voting rights — that is the job, not a list of every heading.

APA keyword line (template using UNC’s Andrews terms)

Keywords: social movements, Civil Rights Movement, Mississippi, voting rights, desegregation

IEEE and Engineering Abstracts

Engineering venues want a capsule that still works when IEEE Xplore and indexing services show only the paragraph. IEEE Author Center — Structure Your Article and the Editorial Style Manual agree on a single paragraph and a hard ban on numbered equations and numbered citations inside the abstract. The Author Center now also tells authors to highlight what is novel, to include three to five searchable phrases, and to keep mathematical symbols out of the title and abstract because they may not display. That last rule is a display rule, not a license to hide a quantitative result: put the number in words if the symbol will break.

IEEE Author Center, “Abstract”

Your abstract should provide a brief summary of the research conducted, the conclusions reached, and the potential implications of those conclusions.
Consist of a single paragraph up to 250 words, with correct grammar and unambiguous terminology
Be self-contained; without abbreviations, footnotes, references, or mathematical equations
Highlight what is novel in your work
Include 3-5 keywords or phrases that describe the research, with any abbreviations clearly defined, to help readers find your article
Most authors write the abstract last and edit it multiple times before article publication to ensure it accurately captures the entire article.
IEEE recommends that you do not include mathematical symbols in your article title or abstract because they may not display properly.

IEEE Editorial Style Manual for Authors

Abstract, must be one paragraph and between 150 to 250 words.
They shall not contain numbered mathematical equations, numbered reference citations, nor footnotes.
Every published article must contain an Abstract.
All articles must contain Index Terms. These are keywords provided by the authors. Index Terms appear in alphabetical order and as a final paragraph of the Abstract section. Capitalize the first word of the Index Terms list; lowercase the rest unless capitalized in text. Include the definition of an acronym followed by the acronym in parentheses.

The Author Center's “without abbreviations” rule and the Style Manual's “define the acronym on first use” rule look like a conflict. Treat them as one instruction: do not drop an undefined acronym into the paragraph; if the term is unavoidable, spell it once and put the acronym in parentheses, then repeat that definition in Index Terms. IEEE's own worked Index Terms list is the model.

IEEE Editorial Style Manual — official Index Terms example

Index Terms—Abstraction, computer-aided system engineering (CASE), conceptual schema, data model, entity type hierarchy, ISO reference model, layered architecture meta model, reverse engineering.

Philip Koopman's widely cited How to Write an Abstract (Carnegie Mellon, October 1997) is the engineering checklist UNC itself adapts: motivation, problem statement, approach, results, conclusions. His own abstract of that essay is the worked example.

Koopman (1997), the article’s own abstract

Because on-line search databases typically contain only abstracts, it is vital to write a complete but concise description of your work to entice potential readers into obtaining a copy of the full paper. This article describes how to write a good computer architecture abstract for both conference and journal papers. Writers should follow a checklist consisting of: motivation, problem statement, approach, results, and conclusions. Following this checklist should increase the chance of people taking the time to obtain and read your complete paper.

ICMJE Structured Abstracts and CONSORT 2025 Trial Abstracts

Medical journals do not want a one-paragraph teaser. The ICMJE Recommendations (updated January 2026) require structured abstracts for original research, systematic reviews, and meta-analyses. Headings differ by journal. The content does not: background, purpose, basic procedures, main findings with effect sizes, principal conclusions, and a warning against overinterpretation. Clinical-trial abstracts must also cover the items CONSORT treats as essential. Put the trial registration number at the end of the abstract when one exists. If the data live in a public repository, ICMJE also wants the persistent dataset identifier, repository name, and number at the end of the abstract.

ICMJE Recommendations, “Abstract” (January 2026)

Original research, systematic reviews, and meta-analyses require structured abstracts.
The abstract should provide the context or background for the study and should state the study's purpose, basic procedures (selection of study participants, settings, measurements, analytical methods), main findings (giving specific effect sizes and their statistical and clinical significance, if possible), and principal conclusions. It should emphasize new and important aspects of the study or observations, note important limitations, and not overinterpret findings.
Because abstracts are the only substantive portion of the article indexed in many electronic databases, and the only portion many readers read, authors need to ensure that they accurately reflect the content of the article. Unfortunately, information in abstracts often differs from that in the text.
The ICMJE recommends that journals publish the clinical trial registration number at the end of the abstract.
If the data have been deposited in a public repository and/or are being used in a secondary analysis, authors should state at the end of the abstract the unique, persistent data set identifier, repository name and number.
Funding sources should be listed separately after the abstract to facilitate proper display and indexing for search retrieval by MEDLINE.

ICMJE then points trial authors to CONSORT. The CONSORT 2025 explanation and elaboration (Hopewell, Chan, Collins, et al., BMJ 389:e081124) updates the CONSORT for Abstracts list as item 1b. Copy the journal's heading names; report these facts under them. Do not invent a trial to fill the list.

CONSORT 2025 item 1b (Hopewell et al., BMJ)

We strongly recommend the use of structured abstracts for reporting randomised trials.
Structured summary of the trial design, methods, results, and conclusions
Do not report information that does not appear in the body of the paper

CONSORT 2025 expanded checklist — facts the structured abstract should name:

  • Specific objectives
  • Trial design (for example parallel group or cluster) and framework (superiority, equivalence, non-inferiority, or exploratory)
  • Eligibility criteria and settings
  • Intervention(s) and comparator(s) for each group
  • Primary outcome(s)
  • How participants were allocated (for example centralised computer-generated randomisation)
  • Who was blinded after assignment
  • Number randomised to each group
  • Number analysed in each group for the primary outcome
  • Primary-outcome result for each group, with estimated effect size and precision
  • Important harms or unintended events for each group
  • General interpretation of the results
  • Name of trial register and identification number
  • Sources of funding — CONSORT lists this in the abstract; ICMJE lists the funding statement after the abstract. Follow the journal.

Nature’s Summary Paragraph Is a Different Genre

Do not paste an IEEE or APA abstract into Nature. The Nature formatting guide wants a fully referenced summary paragraph aimed at readers outside the discipline. It should usually stay under 200 words, avoid numbers, abbreviations, acronyms, and measurements unless they are essential, and introduce the main conclusion with “Here we show” or an equivalent. That referenced opening is the opposite of IEEE's no-citation rule. Use it only when that journal, or a Nature-family journal with the same instruction, is the venue.

Nature formatting guide — Articles

Articles start with a fully referenced summary paragraph, ideally of no more than 200 words, which is separate from the main text and avoids numbers, abbreviations, acronyms or measurements unless essential. It is aimed at readers outside the discipline.
This summary paragraph should be structured as follows: 2-3 sentences of basic-level introduction to the field; a brief account of the background and rationale of the work; a statement of the main conclusions (introduced by the phrase 'Here we show' or its equivalent); and finally, 2-3 sentences putting the main findings into general context so it is clear how the results described in the paper have moved the field forwards.

How to Write the Paragraph: Reverse Outline, Then Cut

UNC's process is the one that survives a 250-word limit. Do not start from a blank sentence that begins "This paper explores various aspects." Finish the draft, reverse-outline each section into one sentence, then revise those sentences into one paragraph. Purdue OWL's version of the same advice is IMRaD compression: one or two sentences per major section. For someone else's article, UNC says the opposite of cut-and-paste: highlight the claims, put the source aside, and write a paragraph in your own words so you do not smuggle in a sentence the original never earned.

UNC Writing Center — construction and what to omit

Reason for writing: What is the importance of the research? Why would a reader be interested in the larger work?
Problem: What problem does this work attempt to solve? What is the scope of the project? What is the main argument/thesis/claim?
Methodology: An abstract of a scientific work may include specific models or approaches used in the larger study. Other abstracts may describe the types of evidence used in the research.
Results: Again, an abstract of a scientific work may include specific data that indicates the results of the project. Other abstracts may discuss the findings in a more general way.
Implications: What changes should be implemented as a result of the findings of the work? How does this work add to the body of knowledge on the topic?
Do not refer extensively to other works.
Do not add information not contained in the original work.
Do not define terms.

Toronto adds the proportion rule: emphasize points in the same ratio they receive in the body. A methods-heavy paper should not spend half the abstract on a one-sentence implication. A thesis-driven humanities essay should not bury the claim under background. If the paper is still a methods draft, finish the methodology section before you try to summarize it.

Real Worked Examples (Not Invented Studies)

The examples below are the ones UNC published from identifiable dissertations, Purdue OWL's own published usability article, and Koopman's own abstract above. They are models of compression, not sources to cite as if you ran the study.

UNC uses the first one to show selection: a title such as "Rhetoric and Riot in Rio de Janeiro" does not tell a newspapers-and-politics searcher whether to order the dissertation. The abstract does.

UNC selection example — late First Empire Rio newspapers

This dissertation examines the role of newspaper editors in the political turmoil and strife that characterized late First Empire Rio de Janeiro (1827-1831). Newspaper editors and their journals helped change the political culture of late First Empire Rio de Janeiro by involving the people in the discussion of state. This change in political culture is apparent in Emperor Pedro I’s gradual loss of control over the mechanisms of power. As the newspapers became more numerous and powerful, the Emperor lost his legitimacy in the eyes of the people. To explore the role of the newspapers in the political events of the late First Empire, this dissertation analyzes all available newspapers published in Rio de Janeiro from 1827 to 1831. Newspapers and their editors were leading forces in the effort to remove power from the hands of the ruling elite and place it under the control of the people. In the process, newspapers helped change how politics operated in the constitutional monarchy of Brazil.

UNC humanities example — Kenneth Tait Andrews (SUNY Stony Brook, 1997)

Kenneth Tait Andrews, “'Freedom is a constant struggle': The dynamics and consequences of the Mississippi Civil Rights Movement, 1960-1984,” Ph.D. State University of New York at Stony Brook, 1997. DAI-A 59/02, p. 620, Aug 1998.

This dissertation examines the impacts of social movements through a multi-layered study of the Mississippi Civil Rights Movement from its peak in the early 1960s through the early 1980s. By examining this historically important case, I clarify the process by which movements transform social structures and the constraints movements face when they try to do so. The time period studied includes the expansion of voting rights and gains in black political power, the desegregation of public schools and the emergence of white-flight academies, and the rise and fall of federal anti-poverty programs. I use two major research strategies: (1) a quantitative analysis of county-level data and (2) three case studies. Data have been collected from archives, interviews, newspapers, and published reports. This dissertation challenges the argument that movements are inconsequential. Some view federal agencies, courts, political parties, or economic elites as the agents driving institutional change, but typically these groups acted in response to the leverage brought to bear by the civil rights movement. The Mississippi movement attempted to forge independent structures for sustaining challenges to local inequities and injustices. By propelling change in an array of local institutions, movement infrastructures had an enduring legacy in Mississippi.

Andrews and the Rio abstract both open with "This dissertation examines…". That is a legal first sentence. The failure is a first sentence that names no object, no claim, and no method — not the words This paper or This study.

UNC science example — Luis Lehner (University of Pittsburgh, 1998)

Luis Lehner, “Gravitational radiation from black hole spacetimes,” Ph.D. University of Pittsburgh, 1998. DAI-B 59/06, p. 2797, Dec 1998.

The problem of detecting gravitational radiation is receiving considerable attention with the construction of new detectors in the United States, Europe, and Japan. The theoretical modeling of the wave forms that would be produced in particular systems will expedite the search for and analysis of detected signals. The characteristic formulation of GR is implemented to obtain an algorithm capable of evolving black holes in 3D asymptotically flat spacetimes. Using compactification techniques, future null infinity is included in the evolved region, which enables the unambiguous calculation of the radiation produced by some compact source. A module to calculate the waveforms is constructed and included in the evolution algorithm. This code is shown to be second-order convergent and to handle highly non-linear spacetimes. In particular, we have shown that the code can handle spacetimes whose radiation is equivalent to a galaxy converting its whole mass into gravitational radiation in one second. We further use the characteristic formulation to treat the region close to the singularity in black hole spacetimes. The code carefully excises a region surrounding the singularity and accurately evolves generic black hole spacetimes with apparently unlimited stability.

Lehner front-loads why the problem matters, then the method, then a result with a concrete comparison. That is Koopman's checklist in the wild. It is also a reminder that first person ("we have shown") appears in real science abstracts even though Toronto prefers to avoid I and we when an active verb can carry the sentence.

Purdue OWL reprints the abstract of its own published OWL-usability chapter as an IMRaD model. The study is real: two generations of usability tests, a prototype comparison, and a timed finding.

Purdue OWL example — Driscoll, Brizee, Salvo, and Sousa (2008)

Dana Lynn Driscoll, H. Allen Brizee, Michael Salvo, and Morgan Sousa, “Usability and User-Centered Theory for 21st Century OWLs,” in The Handbook of Research on Virtual Workplaces and the New Nature of Business Practices, edited by Kirk St. Amant and Pavel Zemlansky (Hershey, PA: Idea Group Publishing, 2008).

This article describes results of usability research conducted on the Purdue Online Writing Lab (OWL). The Purdue OWL is an information-rich educational website that provides free writing resources to users worldwide. Researchers conducted two generations of usability tests. In the first test, participants were asked to navigate the OWL and answer questions. Results of the first test and user-centered scholarship indicated that a more user-centered focus would improve usability. The second test asked participants to answer writing-related questions using both the OWL website and a user-centered OWL prototype. Participants took significantly less time to find information using the prototype and reported a more positive response to the user-centered prototype than the original OWL. Researchers conclude that a user-centered website is more effective and can be a model for information-rich online resources. Researchers also conclude that usability research can be a productive source of ideas, underscoring the need for participatory invention.

Pick the Venue Before You Pick the Sentence

The same finished paper can need four different capsules. The failure mode is pasting the IEEE paragraph into Nature, or the CONSORT heading list into an APA student essay.

Venue rules that actually change the paragraph
VenueShapeCitations insideResults
APA student paperUsually none; if required, one unindented paragraph, ≤250 words, optional Keywords:Almost neverYes, if the paper has them
IEEE journal / conferenceOne paragraph, 150–250 words, plus alphabetical Index TermsNo numbered citations, footnotes, or numbered equationsYes, including what is novel
ICMJE / CONSORT trialStructured headings; registration number at the endJournal-specific; do not add facts missing from the paperEffect sizes, n per group, harms
Nature ArticleReferenced ~200-word summary; “Here we show”Yes — fully referencedYes, usually without extra numbers or acronyms
Toronto SGS thesis150 words (master's) or 350 (doctoral), double-spaced, no figuresNot a place for a literature reviewYes — the thesis you submitted
Conference programOften 50–75 words (Purdue OWL)Almost neverOnly if the talk already has them

Failure Modes Students Actually Hit

  • Abstract–text mismatch: ICMJE and CONSORT 2025 both flag this. A p value, sample size, or conclusion that is not in the paper is a reporting error, not a style slip.
  • Hidden results: a descriptive teaser in a journal that wants an informative or structured abstract. Readers and indexers need the finding.
  • Repeated title: Toronto's first mechanical rule. If the title is already "Sleep duration and GPA," do not open with "This paper studies sleep duration and GPA."
  • Undefined abbreviations and equations: IEEE forbids abbreviations, footnotes, references, and mathematical equations in the abstract, and now warns that symbols may not display. APA and Toronto also tell you not to spend words defining terms.
  • Citations inside the paragraph: IEEE bans numbered citations. UNC says do not refer extensively to other works. Nature is the exception that wants a fully referenced summary. Name a method only when the paper's contribution is that method.
  • Wrong venue capsule: an IEEE paragraph in Nature, a CONSORT heading list in an APA course paper, or a 250-word journal abstract in a 60-word conference program.
  • Funding in the wrong place: CONSORT 2025 lists funding inside the structured abstract; ICMJE lists the funding statement after the abstract for MEDLINE. Follow the journal, and do not invent a grant number.
  • Student-paper extras: adding Abstract and Keywords to an APA course paper that never asked for them, then losing points for format.
  • Invented numbers: do not write "15%" or "r = 0.42" unless that statistic is in your Results.
  • Empty closer: "Implications are discussed" is not a conclusion. Toronto's fourth question needs an actual meaning.

Do

  • Write last, from a reverse outline of the finished draft (UNC, IEEE, Purdue OWL)
  • Match the venue: none / one paragraph / structured headings / Nature summary
  • Put the most important information first (UNC)
  • Include a result or claim the paper can defend
  • Reuse the paper's searchable terms so databases can index it
  • Stay inside the stated limit (APA 250; IEEE 150–250; Toronto SGS 150/350; Nature ~200; conference programs often 50–75)

Don’t

  • Evaluate the work (that is a review, not an abstract)
  • Add a finding, caveat, or citation that is not in the paper
  • Define routine terms or paste a table or figure
  • Hide the result in a journal that asked for an informative abstract
  • Start by repeating the title
  • Copy a sentence from the introduction and call the job done

Revision Checklist

Before you submit

  • The assignment, journal, or graduate office actually wants an abstract
  • A reader who never opens the PDF can still state the claim and the main result
  • Every number, sample size, and limitation also appears in the paper (ICMJE / CONSORT 2025)
  • The type matches the limit: descriptive at ~100 words, informative when the venue wants results
  • APA format is correct if you are in APA: page 2, unindented paragraph, italic Keywords line
  • IEEE abstracts have no numbered citations, footnotes, or numbered equations, and Index Terms are alphabetical
  • Medical structured abstracts include effect sizes and, for trials, the registration number
  • Nature summaries are referenced and use “Here we show” only when that is the venue
  • Keywords or Index Terms name topic, population, or method — not every heading
  • Sources the paper cites are formatted in the assigned style; generate that list with the citation generator

Finish the argument, then write the capsule

An abstract cannot invent a thesis the paper never argued. Tighten the claim, finish the introduction and conclusion, then compress. When the draft is stable, format the sources you actually used.

Abstract FAQs

How long should an abstract be?
There is no one number. Toronto's informative default is about 100–250 words. Purdue OWL's default is about 150–200 words, or 50–75 words for some conference programs. APA 7 limits the paragraph to 250 words unless the instructor or journal says otherwise. IEEE wants 150–250 words in one paragraph. UNC treats 100–120 words as a descriptive guess and 250+ as informative. Nature wants about 200 words. Toronto SGS theses: 150 words for a master's abstract, 350 for a doctoral abstract. Use the limit on the assignment or instructions to authors.
Do APA student papers need an abstract?
Usually no. The APA Style Abstract and Keywords Guide and Publication Manual §2.9 say abstracts and keywords are not typically required for student papers. Add them only if the instructor or department asks, then use the professional format: page 2, bold Abstract heading, one unindented paragraph, optional italic Keywords line.
Should an abstract include results?
Yes, if you are writing an informative or structured abstract — the type journals, IEEE, APA professional papers, ICMJE original research, and CONSORT 2025 trials expect. A descriptive abstract deliberately omits results. Do not write a descriptive teaser for a science paper whose readers need the finding to decide whether to download it.
Can I start with "This paper" or "This study"?
Yes, if the rest of the sentence names the object and the claim. UNC's Andrews and Rio examples both open with "This dissertation examines…". What fails is "This paper explores various aspects of the topic." Toronto's rule is different: do not repeat or rephrase the title in that first sentence. Nature often wants “Here we show” instead of “This paper.”
May I use I or we?
Follow the venue. Toronto prefers to avoid I or we and to keep the verb active ("the study tested"). UNC's humanities example uses I ("I clarify," "I use"); Lehner's science example uses we. IEEE cares more that the paragraph is self-contained and free of abbreviations and equations than that you avoid first person.
Do I put citations in the abstract?
Almost never — except in a Nature-style fully referenced summary paragraph. IEEE forbids numbered reference citations. UNC says do not refer extensively to other works. Toronto says do not point to information that is not in the document. Name a method or theory only when that name is how readers will search for your contribution.
What is a structured abstract?
A labelled summary — Background, Methods, Results, Conclusions, or the journal's own headings — rather than one untitled paragraph. ICMJE requires that shape for original research, systematic reviews, and meta-analyses. CONSORT 2025 item 1b lists the facts a randomised-trial abstract should name, including n per group, the primary-outcome effect with precision, harms, registration, and funding. Copy the headings from the journal you are submitting to; do not invent a heading list.
Where do I put the trial registration number and the funding statement?
ICMJE wants the clinical trial registration number at the end of the abstract, and the persistent dataset identifier there too if the data are in a public repository. ICMJE wants funding listed separately after the abstract for MEDLINE. CONSORT 2025 item 1b also lists sources of funding among the abstract facts. Follow the target journal's heading list rather than merging the two documents into one invented block.
When should I write the abstract?
Last. IEEE says most authors write it after the article exists and edit it more than once. UNC's reverse-outline method and Purdue OWL's IMRaD compression only work on a finished draft. If you write the abstract first, you will either hide results you have not measured or lock a claim the paper later abandons.
How is an abstract different from an introduction or a conclusion?
The introduction frames the gap for a reader who will continue. The conclusion assumes the reader has just finished the body and is ready for significance. The abstract is indexed on its own and often reports results so a stranger can decide whether to open the file. Do not paste the abstract into the first or last section.
How do I choose keywords?
APA wants three to five terms for topic, population, method, or application; lowercase except proper nouns; no period at the end. IEEE Index Terms are alphabetical and define acronyms — the Style Manual's CASE list is the model. UNC and Toronto both say the abstract itself should already contain the search phrases a database will mine. Do not list every heading, and do not invent keywords the paper never uses.