1. Descriptive abstracts
- Tell readers what information the article contains
- Include the purpose, methods, and scope of the article
- Do not provide results, conclusions, or recommendations.
- Are always very short, usually under 100 words.
- Introduce the subject to readers, who must then read the article to find out the author's results, conclusions, or recommendation
2. Informative abstracts
- Communicate specific information from the article
- Include the purpose, methods, and scope of the article
- Provide the article's results, conclusions, and recommendations.
- Are short -- from a paragraph to a page or two, depending upon the length of the original work being abstracted. Usually informative abstracts are 10% or less of the length of the original piece.
- Allow readers to decide whether they want to read the article
Essential elements of the abstract are:
- Background: A simple opening sentence or two placing the work in context
- Aims: One or two sentences giving the purpose of the work.
- Method(s): One or two sentences explaining what was done. (Described at length only if it is unusual)
- Results: One or two sentences indicating the main findings. (Absolutely essential)
- Conclusions: One sentence giving the most important consequence of the work. (Telling what the results mean).
Source: http://www.olemiss.edu/depts/writing_center/grabstract.html