This issue brief discusses value-based payment (VBP) models implemented by public and private health plans to enhance the quality and efficiency of the U.S. healthcare system. It outlines the process of patient attribution, where patients are assigned to providers in VBP models, and highlights the challenges providers face in understanding their patient assignments. The brief presents findings from the 2023 CAQH Index, which surveyed medical providers about their ability to determine patient attribution and the methods used for exchanging this information. It details the shift towards electronic health records for sharing attribution data, indicating progress in reducing administrative burdens. The report also examines the frequency of data exchange and the time providers spend reviewing attribution information, noting improvements since 2020. The brief concludes by emphasizing the need for continued enhancements in communication methods to support the effective implementation of VBP models and improve overall health outcomes.