Price transparency project: Informing the development of Plan S

This article reports on the outcome of a project launched in September 2019 to develop an approach to implementing the price transparency principle of Plan S. It was clear from the outset that mobilising stakeholder engagement and support would be crucial to success. It was also clear that this would be a challenge. While funders, libraries, and library consortia were broadly supportive of the work, many publishers - both mixed model and OA-only - expressed significant concerns. A framework consisting of title, contextual, and price metadata emerged and is described within. © 2020 - IOS Press and the authors. All rights reserved.