Peer review is the evaluation of work by one or more people with similar competences as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review is designed to assess the validity, quality and often the originality of articles for publication. Its ultimate purpose is to maintain the integrity of science by filtering out invalid or poor quality articles. From a publisher’s perspective, peer review functions as a filter for content, directing better quality articles to better quality journals and so creating journal brands. Running articles through the process of peer review adds value to them. For this reason publishers need to make sure that peer review is robust.