It is a type of summary, and often it is called just that: summary. Abstracts may be found at the beginning of a research paper, in a conference programme, or in special collections of abstracts. Abstracts from all reputable medical journals are entered in an electronic data-base available in universities all over the world. People who do not have access to the entire article, read only the abstracts, so abstracts must be informative, despite their brevity. The essence must be given in such a form that they can stand alone and be understandable. This is why they are “miniversions” of articles or papers and have a very conventional format. In other words, an abstract is a synopsis[1], not an introduction to the article.
The abstract should answer the question: What should readers know after reading this article?
And, more specifically, it should answer the following:
Why did they do it?
How did they do it?
What did they find?
What does it mean?
In a paper or article, the abstract appears following the title page.
The length of an abstract may be anything from 50-200 words, according to the importance of the study and the guidelines given by the publishers.
There are variations to the format of an abstract, depending on the journal. The structured abstract (i.e., an abstract that has 5 sections: introduction, objective, methods, results, and conclusions) has become the standard for most research articles, whereas reviews, case reports, and certain other types of special articles have nonstructured abstracts.
The BMJ gives the following format for the structured abstract:
Objective
Design
Setting
Subjects
Main outcome measure
Results
Conclusions
Some journals use one of these:
Background Introduction
Purpose Objective
Participants Subjects
Findings Results
Interpretation Conclusion
Yet, the following headings are the most frequently used:
Objective(s)
Methods
Results
Conclusions
Objective: To state the purposes of the study or investigation, the hypothesis being tested or the procedure being evaluated.
The structure that is most often used in English to express purpose is the Infinitive:
To evaluate the utility…
To present our experience…
To study the diagnostic value of…
To assess
To compare
To determine
To perform
To develop
To demonstrate
To investigate
To ascertain
To design
To establish
We can also use a noun:
The purpose/aim/objective/goals of this study is/are to…
Materials and methods/Subjects[2]: Briefly state what was done and what materials were used, including subjects or participants. Mention the methods used to assess the data and to control bias.
-
patients with…were included…
-
patients known to have/suspected of having…
…was performed in n patients with…
-
patients underwent…
Patients were followed clinically for…months/years…
Quantitative/Qualitative analyses were performed by…
We examined the effects of…on….,during….in 20 healthy volunteers.
Results: Provide the findings of the study, including indicators of statistical significance. Include actual numbers, as well as percentages.
Between… and… the number of… increased/decreased from… to.
The clinical manifestations of… were not significantly different, but there were certain characteristic features in their neuroimage.
The pre- and post-operative grades of motor disturbance showed a better, positive linear correlation.
Histological examination revealed…[3]
Conclusion: Summarize in one or two sentences the conclusion/s made on the basis of the findings. It should emphasize new, important aspects of the study or observations.
A conclusion may be definitive
We can conclude that…
The study data demonstrate….
It seems certain therefore that…
Or it may be hedged, if the author avoids giving a direct or strong commitment to a position or point of view, without seeming to be too vague, though.
Of course, both possibilities remain…
We cannot help but wonder whether…
….may play a role in…
Our study/ experience suggests that…
The introduction or purpose can often be stated in a single sentence. The objective should be stated in one imperative-style sentence. Describe the methods and the main results in 3-4 sentences each. Carefully select the most important data and statistics to show and/or describe in the results section. Just state the main results. The conclusion, like the introduction can typically be handled in 1 or 2 sentences. Try summing up the findings in the first sentence and then make a conclusion in the second.
Typical Pattern of Verb Tenses in Abstracts[4]
Background information: PRESENT SIMPLE or PRESENT PERFECT
Purpose: PAST TENSES
Methods: PAST TENSES
Results: PAST TENSES
Conclusions: PRESENT TENSES, PAST TENSES, TENTATIVE VERBS, MODAL VERBS
General Final Advice
Do not speculate or include opinions in the abstract. The abstract is a “just the facts” presentation of your research.
The abstract’s major emphasis should be the methods and the main results.
Do not repeat the title in the abstract.
Do not use the same sentences you used in the article or paper.
Write your abstract AFTER you have written your paper, not before.
Stress what is special in your study.