Open Access

Open access (OA) is apublishingmodel forscholarly communicationthat provides free, immediate, and unrestricted online access to peer-reviewed research articles, permitting users to read, download, copy, distribute, print, search, or link to the full texts for any lawful purpose, subject only tointernet accessconstraints.[1][2]Originating in the late 1990s with initiatives like thearXivpreprintrepository and formalized by the 2002 Budapest Open Access Initiative, OA emerged as a response to escalating subscription costs and restricted dissemination in traditionalacademic publishing.[3][1]OA operates through primary routes such as gold OA, where publishers make articles immediately available upon payment of article processing charges (APCs) by authors or funders, and green OA, which allowsself-archivingof author manuscripts in institutional or subject repositories after an embargo period.[4][5]Hybrid models in subscription journals offer OA options for individual articles via APCs, though these have drawn criticism for "double dipping" revenues from both subscriptions and fees.[6]Despite achievements in broadening access—particularly in fields like physics andbiomedicine—OA faces controversies, including the proliferation of predatory journals that charge APCs without adequatepeer review, undermining quality, and mixed empirical evidence on a purported citation advantage for OA articles.[7][8][9]