Subscribe to Open (S2O) is an economic model used by peer-reviewed scholarly journals to provide readers with open access (OA) to the journal’s content, without charging costs to authors. S2O converts journals that have a traditional subscription model to open access.[1][2][3]
When the academic libraries subscribing to a journal are asked to renew their subscriptions to the journal, they are told that, with the libraries’ support, the journal will be made open access to all readers, while authors are able to publish in it at no cost. If enough libraries renew on these terms, the journal is converted to open access, and if not, access to the journal remains restricted to subscribing libraries.[1][2][3]