An abstract is a short, self-contained summary of a paper, usually 150 to 250 words, that states the purpose, methods, main findings and conclusions. Readers use it to decide whether to read the whole paper.

Should I write the abstract first or last?

Write it last. You cannot accurately summarize a paper until it is finished. Draft it after the conclusion, then check it against the final version of the paper.

Do I include references in an abstract?

Generally no. An abstract should stand alone and summarize your work, so it avoids citations, quotations, tables and figures. A few disciplines make exceptions, so follow submission guidelines.

What is the difference between an abstract and an introduction?

An abstract summarizes the entire paper, including results and conclusions. An introduction sets up the topic and argument but does not reveal everything. The abstract is a stand-alone summary, while the introduction is part of the paper.

What are keywords for?

Keywords are a few terms listed under the abstract that help databases and readers find your paper. Choose specific terms that people would search for, and avoid words that merely repeat the title.

Writing an Abstract: How to Summarize a Paper Clearly

An abstract is a single paragraph that carries a heavy load. For many readers, it is the only part of your paper they will ever read. It decides whether a researcher downloads the full paper, whether a conference committee accepts your submission and whether your instructor sees right away that you understand your own work.

Because it is short, it must be precise. This guide covers what goes into an abstract, how to write one in a sequence of steps, how to tailor it to different types of papers and which mistakes to avoid.

What an abstract does

A good abstract is self-contained. Someone who reads only that paragraph should know what you studied, how you studied it, what you found and what it means. It is a miniature version of the paper, in the same order.

It is not a teaser. Unlike a back-cover blurb, an abstract states the results. It is also not an introduction. It should not leave the reader guessing about your conclusion.

Two types

Most academic abstracts fall into one of two categories.

Type	What it does	Typical use
Informative	Summarizes purpose, methods, results and conclusions with key data	Research papers, lab reports, theses
Descriptive	Describes what the paper covers without giving results	Some humanities essays, reviews and long reports

Check your discipline and the instructions. When in doubt, informative abstracts are the norm in sciences and social sciences.

The five-part formula

Most informative abstracts answer five questions, in this order.

Background or purpose. What problem or question does the paper address? Use one or two sentences.
Methods. What did you do? Mention the design, sample or materials and approach, briefly.
Results. What did you find? Include the most important numbers or trends.
Conclusion. What do the results mean?
Implications. Why does it matter, or what should happen next?

For a 200 word abstract, you might spend about 30 words on background, 40 on methods, 70 on results and 60 on conclusions and implications.

A worked example

Here is a short informative abstract for a hypothetical study:

Many universities require first-year students to attend study skills workshops, but evidence on whether these programs improve grades is mixed. This study examined whether attendance at a four-week workshop was associated with course performance among 640 first-year students at a public university. Students who attended at least three sessions were compared with matched non-attendees using end-of-term grade point averages. Attendees earned a mean GPA 0.21 points higher than non-attendees, after adjusting for prior achievement, and the difference was largest among students with lower entry scores. These findings suggest that brief workshops may provide the greatest benefit to students at risk of falling behind, although self-selection may account for part of the effect. Universities should consider targeting workshops to lower-scoring entrants and evaluating them with randomized designs.

It follows the five parts in about 130 words. (The study is invented to illustrate the form.)

Step-by-step process

Step 1: Finish the paper

Do not write the abstract from a plan. Wait until you have the results and conclusions fixed.

Step 2: Find the key sentence in each section

Skim your paper and underline the one or two sentences in each section that carry the main message: the research question, the method, the main result and the conclusion.

Step 3: Combine and condense

Put those sentences in order, then rewrite them as a continuous paragraph. Cut details that are not necessary for understanding. Replace long phrases with shorter ones.

Step 4: Check the word limit

Many instructors, conferences and journals set a limit, often between 150 and 250 words, and some allow 300 or more. Follow the exact limit given. If there is none, aim for about 150 to 200 words.

Step 5: Compare with the paper

Check each statement against the final paper. The numbers, terms and conclusions in the abstract must match. Mistakes here are among the most noticeable errors in academic writing.

Step 6: Choose keywords

If required, add three to six keywords below the abstract. Choose terms a researcher would use to find your work, such as "study skills", "first-year students" and "academic performance". Use specific terms and avoid generic words.

Writing style

Use plain, direct sentences. Avoid long strings of clauses.
Use past tense for what was done and found, and present for conclusions that the evidence supports now.
Avoid jargon and abbreviations where possible. If you must use them, define them.
Do not cite sources in the abstract unless your field requires it.
Do not include information that is not in the paper.
Write one paragraph, unless a structured format with headings is required.

Structured abstracts

Some fields, especially health sciences, use structured abstracts with headings such as Background, Methods, Results and Conclusions. The content is the same, but each part is labeled. If your course or journal specifies this format, follow it exactly. Even if it does not, the headings can help you check that you have covered every element.

Abstracts for other documents

The same approach adapts to other work.

Lab report. Emphasize the hypothesis, method and main numerical results. See the guide on lab reports for the full structure.
Thesis or dissertation. The abstract is longer, often up to 350 words, but follows the same order.
Conference abstract. It may be a proposal, so describe what you will present and why it is important, and include preliminary results if you have them.
Humanities essay. A descriptive abstract may state the topic, the argument and the evidence you analyze.

Cutting an abstract down

Most first drafts run long. When you need to trim, work in this order.

Remove background that the intended reader already knows.
Shorten the method to the design and sample, and drop procedural detail.
Keep only the most important results, usually two or three numbers.
Replace phrases such as "it was found that" with direct statements.
Delete adjectives and adverbs that do not change meaning.

Read the shortened version aloud. If every sentence still carries information the reader needs, stop cutting.

Before and after

A bloated sentence: "In the present study, an investigation was carried out in order to examine the extent to which there might be a relationship between hours of sleep and grades." A tighter version: "This study examined the relationship between sleep and grades." The second says the same thing in about a third of the words, and an abstract has no room for the first.

Take the same care with your verbs. Strong abstracts use specific verbs such as measured, compared, tested and found. Weak ones rely on vague phrases such as looked at, dealt with and was concerned with.

For a thesis or a journal submission, a careful edit of the abstract is worth the effort, since it is the most-read paragraph. A second reader helps here too, and editing for graduate papers and manuscripts is one way to get one.

Common mistakes

Writing it too early. The abstract may not match the final paper.
Being vague. "Results are discussed" tells the reader nothing. State the results.
Overloading with detail. Include only what the reader needs.
Including new information. Everything in the abstract must appear in the paper.
Copying sentences from the introduction. Write a fresh summary.
Ignoring the word limit. Too long can lead to rejection.
Leaving out the conclusion. The reader should know your main takeaway.

Final checklist

Does it state the purpose or question?
Does it describe the method?
Does it report the main results?
Does it give a clear conclusion?
Does it stand alone without the paper?
Is it within the word limit?
Do all facts and numbers match the paper?
Have I chosen useful keywords?

Final thoughts

Treat your abstract as the most-read paragraph in your paper. Write it last, follow the order of the paper, include real results and read it as a stranger would. When it tells a clear, accurate story in a couple of hundred words, readers will know what you did and why it matters, and they will be far more likely to read on.