Abstracts are important because they give a first impression of the document that follows, letting readers decide whether to continue reading and showing them what to look for if they do. Though some abstracts only list the contents of the document, the most useful abstracts tell the reader more. An abstract should represent as much as possible of the quantitative and qualitative information in the document, and also reflect its reasoning. 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?
If the paper is about a new method or apparatus the last two questions might be changed to
- What are the advantages (of the method or apparatus)?
- How well does it work?
Here are some other points to keep in mind about abstracts:
- 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.
- Your readers expect you to summarize your conclusions as well as your purpose, methods, and main findings. Emphasize the different points in proportion to the emphasis they receive in the body of the document.
- 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).
- Avoid if possible avoid trade names, acronyms, abbreviations, or symbols. You would need to explain them, and that takes too much room.
- Use key words from the document. (For published work, the abstract is “mined” for the words used to index the material—thus making it more likely someone will cite your article.)