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: