Effect of Hearing Aid Insurance Coverage Requirements for Adults on Utilization Abstract Hearing loss affects 23% of those aged 12 and older in the U.S. More than 2/3 of U.S. adults over the age of 70 have significant hearing loss. The most efficacious management option for most individuals with hearing loss is the use of hearing aids (i.e., a small removable electronic device that is worn in or behind the ear to amplify sound), which can improve communication and quality of life. Hearing aids are generally not covered by insurance and about 86% of hearing loss cases go untreated. However, Medicaid provides hearing aid benefits in 28 states and 8 states require private insurance benefits for at least some adults. These coverage requirements may improve hearing aid uptake by reducing costs as a barrier. The long-term goal of our research agenda is to understand the effects of improving hearing on health. Specifically, the objective of our current application is to use quasi-experimental (e.g., difference-in-differences) evaluation methods to estimate the effect of coverage requirements in Medicaid and private insurance plans on hearing aid use. We will use high quality, reproducible Anthem private insurance claims data, National Health Interview Survey (NHIS) data, Medicaid claims-linked NHIS data, and Medicare Current Beneficiary Survey (MCBS) data to study: (i) the effect of state private insurance coverage requirements for hearing aids on beneficiary hearing aid purchasing and out-of-pocket payments in fully-insured health insurance plans; (ii) the effect of Medicaid and private insurance coverage requirements on use of hearing aids in the NHIS, and Medicaid coverage requirements in the Medicaid-linked NHIS and MCBS (for dual-eligibles); and (iii) the effect of private and Medicaid requirements by demographic group. Our project is significant by focusing on high rates of untreated hearing loss; by estimating the effects of state implementation of private and public insurance coverage requirements on hearing aid adoption among U.S. adults (which provides evidence for the effects of pending national legislation); and by providing evidence on whether hearing aid coverage requirements improve well- documented disparities in hearing aid use for males, racial/ethnic minorities, and lower-educated individuals. Our project is innovative by being the first to use quasi-experimental difference-in-differences methods (which can provide causal evidence) for hearing health care research, including newer methods accounting for heterogeneous treatment effects; leveraging powerful sources of currently under-used data to study hearing health care access and utilization; constructing detailed coverage requirement data through original policy research that we will make available publicly. The research team includes experts in clinical audiology, health economics, advanced statistical modeling, insurance claims data, and health policy. The proposed project will ha...