PROJECT SUMMARY/ABSTRACT Hearing loss affects over 70% of US adults at some point in their lifetime and has significant effects on patient quality of life and overall health. Effective treatment for mild to moderate hearing loss includes hearing aid provision, but over 80% of adults with hearing loss do not use a hearing aid. One factor contributing to this treatment gap is lack of awareness of hearing loss and no uniform guidance around hearing screening in adults. Current guidelines on US adult hearing screening are conflicting, and overall rates of screening in the US are low despite the potential for early detection and linkage to beneficial care. This lack of uniform guidelines is in part due to the absence of sufficient quantitative evidence on the long- term clinical and economic effects of adult hearing screening strategies in the US. The proposed research seeks to address this evidence gap and has the long-term goal of helping US clinical and policy decisionmakers identify the most effective and cost-effective adult hearing screening programs for their populations. Aim 1 develops and validates a decision modeling framework of adult hearing screening, diagnosis, and treatment in the US. These modeling efforts are in conjunction with an ongoing Lancet Commission on Hearing Loss that will provide clinical and policy expert guidance and support. Aim 2 will utilize the modeling framework from Aim 1 to project clinical and economic effects of alternative adult hearing screening programs in the US. The analysis will project costs and benefits of screening interventions that vary by age at first screen, screening frequency, and screening test modality. Aim 3 will estimate the economic benefit obtained from reductions in uncertainty of model inputs that can be achieved through future research. This Aim will inform future adult hearing screening research prioritization through value of information analysis. The results of these three Aims will clarify optimal policy and investment in research targeting adult hearing screening in the US. This fellowship application is designed to prepare the PI to achieve his long-term goal of becoming an independent physician scientist using decision science to increase the value and provision of care for aging populations. Towards that long-term goal he will develop skills in advanced methods in decision science and population health sciences, maximize the policy relevance of his research, gain further clinical experiences and integrate clinical knowledge into his research, and build professional skills key to a successful career. The rigorous clinical and research training proposed will enable the PI to be well-positioned for his future career as a clinician investigator.