An abstract usually appears before an article or report and gives the readers a breakdown of its major components. Abstracts help save readers time by giving them necessary information upfront and helping them decide whether to continue reading or not. After reading the abstract, a reader should have sufficient guideposts for what to expect when they continue to the article or report.
An abstract has to be easy for even people outside of the discipline to read and understand (see References 1). Abstracts should be free of technical jargon unless they are clearly defined within the abstract, the main ideas behind the project should be clear and easy to understand. The standardized format of an abstract makes ease of comprehension possible.
An abstract should be short. Although you may not have exact word limits when writing an abstract, you should try to keep it to one or two paragraphs. In an abstract, only include the most vital information, since readers who want more information will simply read about it in the article.
Abstracts should present information in an organized fashion. In many disciplines, the standard format for organizing an abstract is to present the purpose, methods, scope, results, conclusions and recommendations of a study. Some abstracts, especially descriptive abstracts, may not have the the results, conclusions and recommendations.
An abstract is not the place to make value judgments on your own or another researcher's work. It should be written in an unbiased and objective manner, and should merely mirror what is contained in the article.