This dissertation examines the determinants of competition and consumer access in the health care market, and supply- and demand-side determinants of health care use under the Affordable Care Act (ACA). The first essay studies insurer entry into the federally-facilitated health insurance market under the ACA. Motivated by the fact that insurers’ service areas can be subsets of rating areas, and the substantial variation in plan composition within a rating area, I explore variations in the type of plans offered and insurers’ decisions to enter a rating area. I find that availability of medical providers, population size, and metropolitan status are important in insurers’ decisions to enter a rating area. Medical cost affects the entry of restricted network plans. The second essay examines how supply-side incentives affect treatment choice for depression. Using claims data from Florida’s Medicaid program, I find large variations in initiating antidepressant treatment among newly diagnosed patients with three plan types: Fee-for-Service (FFS), Primary Care Case Management (PCCMs) and Accountable Care Organizations (ACOs). Compared to FFS, PCCMs and ACOs are more likely to provide antidepressant but no office-based care. I use the control function approach to mitigate the self-selection bias and find that ACOs tend to use lower cost medication options. Despite the use of low-cost alternatives for ACOs, no differences are found in subsequent psychiatric hospitalization or emergency room visits among plans. Different provider contractual relationships may partially explain treatment choice differences. The third essay investigates whether the ACA policy of free preventive services affects utilization of preventive care. I use variation in commercially-insured enrollees to examine the demand and supply prices of four preventive services. Despite an average 53 percentage point decrease in demand prices for these services, the actual service use only increased by 17 percent from 2007 to 2011, possibly due to little or no change in prices paid to providers. Using risk adjustment tools to predict and control for patient underlying health status, I find similar changes in demand prices and rates of service use across six health plan types, consistent with preventive visits being provider rather than consumer choices.

This study seeks to provide information relevant to public policy that will lead to increased access and utilization among this vulnerable population and to reinforce the validity of the behavioral model for vulnerable populations. This study is a secondary analysis of data collected in a study that examined adult, working-aged patients within the John Peter Smith Health Network, which is a large, urban, tax supported county health care system in Fort Worth, Texas. From a sampling frame of 10,000 patients, the study analyzed data for 243 low-income, white, working-age males, collected from computer assisted telephone interviews in 2000. Cross-tabulations and bivariate logistic regressions were used to analyze the effect of 8 independent variables (age, marital status, insurance, employment status, a usual source of care, competing needs, experiences with paperwork, and perceived health status upon 5 dependent variables pertaining to unmet health care, unmet prescription medicine needs, unmet dental needs, utilization of doctors in emergency departments, and overnight hospital stays. The results show the safety net system is failing to meet the needs of this vulnerable population. The findings indicate white men who found it necessary to forgo health care due to other needs were almost five (4.973) times as likely as those who did not find it necessary to forgo care due to other needs, to report having a problem getting the health care that they need (p = ≤ .001). The odds of having a problem getting needed dental care are about 66% lower for white men who have private insurance through work compared to those who do not have private insurance through work (p ≤ .05).