This project aims to advance methodological and theoretical approaches for developing, selecting, refining, and piloting a multilevel de-implementation strategy to reduce the overuse of screening mammography in women aged ≥75 years. Informed by an innovative participatory, stakeholder-driven innovation tournament and a discrete choice experiment, the research team identified, prioritized, and tailored a multilevel de-implementation strategy. The research team will conduct a cluster randomized controlled trial (at the provider level) to test the impact of the provider- and patient-level components of the multilevel strategy on screening mammography use, and secondarily, on provider referrals/orders for screening mammography. The organizational level components of the multilevel strategy will be implemented among all participants, not via random assignment.