Articles in the sciences and health sciences are often initially posted online as preprints. A preprint is a draft of a scholarly article, made available online before it has gone through the formal peer-review process or been published by a scholarly journal. While preprints allow researchers to disseminate their findings more quickly, the lack of a formal peer-review process means that readers should be especially careful to evaluate the quality of the research. If the preprint is more than a month or two old, search for a final, published version of the article; your librarians can help with this!