OTHER PROJECT INFORMATION – Project Summary/Abstract THE IMPACT OF EXEMPTING MEDICAL PROVIDERS FROM MALPRACTICE LIABILITY Among the most controversial aspects of the U.S. health care system are the impacts of the medical malpractice system on patient treatments and health care costs. Defensive medicine is an unintended effect of the liability system in which physicians order extraneous tests, procedures and other services as a result of fears over medical liability. The debate continues, however, regarding just how large these costs really are. Missing from the literature's attempts to resolve this debate has been a true “treatment” group of medical encounters with respect to which there is no liability recourse at all in the event of negligent care. We aim to further the analysis begun under R01AG049898, in which we drew on institutional features of the Military Health System (MHS) to estimate the effects of immunizing providers from liability, facilitating an unprecedented assessment of the full extent of defensive medicine operating in our system. We propose to continue this research to push the literature beyond its present focus on inpatient care and to place the effects of liability in perspective by comparing liability's effects with other approaches, especially demand-side approaches, to regulating medical encounters. Our focus will be on investigating the impacts of certain policy levers on age-related diseases such as cardiovascular disease, diabetes, and cancer. The proposed continuation will address four aims. First we will explore the impact of medical liability pressure on “high-value” outpatient care, while placing these estimates into perspective by likewise exploring effects on the receipt of “low-value” care (drawing on high- and low-value measures currently emphasized in the medical literature). Second, drawing on a unique feature of the MHS data, we propose to compare the effects on high- and low-value care receipt stemming from the medical liability system – a classic supply-side approach to regulating provider behavior – with those resulting from a classic demand-side approach to regulating the physician-patient relationship: information disclosure to patients. Third, we will place independent emphasis on one of the key dimensions of comparison necessary to execute the liability analysis – that is, the difference in quality and quantity of care provided on the base through a coordinated direct-delivery system with that provided off the base through the MHS's purchased-care system. Fourth, we will explore aspects of each of the above aims specifically in the context of opioid use among the MHS population, while comparing the effects of liability pressure and information disclosure on opioid use with the effects of one of the most oft- discussed stated-based approaches to regulating opioid use: Prescription Drug Monitoring Programs.