PLOS ONE (originally PLoS ONE) is a peer-reviewed open access scientific journal published by the Public Library of Science (PLOS) since 2006. The journal covers primary research from any discipline within science and medicine. Operating under a pay-to-publish model, PLOS ONE publishes approximately 70% of submitted manuscripts. All submissions go through a pre-publication review by a member of the board of academic editors, who can elect to seek an opinion from an external reviewer. According to the journal, papers are not to be excluded on the basis of lack of perceived importance or adherence to a scientific field. Although submissions declined from 2013 to 2014, PLOS ONE remains the world’s largest journal by number of papers published (about 30,000 a year, or 85 papers per day) and has a 2014 journal impact factor of 3.234.