In APA style, an abstract is a brief summary of a research article, thesis, review, conference proceeding, or any in-depth analysis of a particular subject and is often used to help readers quickly ascertain the paper's purpose. The abstract is usually located at the beginning of the paper, and it should be a standalone document that provides a complete and concise summary of the research or study. The abstract should briefly describe the purpose of the study, the research questions or hypotheses, the methods used, the main results, and the conclusions or implications of the study. The length of an abstract can vary depending on the requirements of the paper or publication, but it is typically no more than 250 words.