Abstracts (and Summaries) serve to reduce a long text to its essential key points - summing up the study.
Swales and Feak [Academic Writing for Graduate Students (1994) Univ. of Michigan Press] identify two types of abstract:
- results-driven: concentrating on the
research findings and conclusions
- summary: providing one or two sentence summaries of each of the IMRAD sections of a report
An abstract is generally seen as a more specialized form of summary. Both come at the beginning of a text, and serve to indicate and predict the structure and content of the text which follows.
Both should be composed after the report has been completed.
Now let's look at the typical Structure of an Abstract