PROJECT SUMMARY Our parent project (NIH R01MH125958) is characteristic of a growing number of studies collecting highly gran- ular and sensitive digital phenotyping (DP) data with great promise to advance science and healthcare. DP data, in combination with artificial intelligence and machine learning (AI/ML) is poised to revolutionize clinical ap- proaches to personalized medicine both within and outside of psychiatry. However, DP data also poses potential risks to patients’ privacy and self-determination due to their growing capacity to reveal – and increasingly to predict – emotional and behavioral states undetected by humans. Existing legal protections do not adequately address novel features of the DP data ecosystem which enable applications (including monetization and ex- change of DP data) that are not directly linked to patient benefit and potentially expose patients to risks that are difficult to predict. The objective of this proposal is to identify practical, ethical and technical benefits, challenges and incentives for implementing smart contracts: an emerging privacy-by-design technology with promise to enhance patient control over future uses of their DP data. Our supplement brings together interdisciplinary ex- pertise in bioethics, medical anthropology, decision science/behavioral economics and machine learning . Led by an expert in qualitative and mixed methods, our team will conduct interviews to identify diverse stakeholders’ perceptions and technical understandings about potential benefits, challenges, and ethical considerations for using smart contracts to implement patient data sharing preferences for DP data collected for psychiatric re- search (Aim 1). Informed by Aim 1 findings and using behavioral economics insights, in Aim 2 we will model an optimal “choice architecture” to incentivize diverse stakeholders’ engagement with smart contracts in ways that are ethically justified and align with stakeholder interests. This contribution is significant because it will provide knowledge critical to support collaborations that modernize patient protections within a growing DP data ecosys- tem characterized by complex social, economic, technical and legal relations. Our approach is innovative in that it treats the DP data ecosystem as an ethnographic space comprised of relations between and among human actors as well as technologies emerging in parallel but in the absence of an incentivizing patient -centered frame- work. The work is feasible because our team of established investigators have expertise in ethical , technical, behavioral and policy issues related to DP data use and a track record of success working together on large collaborative projects addressing ethical issues related to emerging technologies including AI/ML.