The goal of my research is to explore ways to improve the welfare of populations that are targeted by public programs. In particular, my thesis consists of three chapters on health insurance and education. The first chapter looks at Medicaid take-up decisions among poor children. Medicaid is public health insurance that is available to low income individuals, and it is provided freely by the government. However, there is a puzzling observation that many low-income children are uninsured despite their eligibility for Medicaid. As one possible explanation, I propose that the low level of access to health care that Medicaid provides can explain incomplete take-up. Existing literature suggests that the low level of Medicaid fee payments to physicians reduces their willingness to see Medicaid patients, creating an access- to-care problem for these patients. Using variation in the timing of the changes in Medicaid payments across states, I find that improving Medicaid generosity increases the take-up rate and reduces the uninsured rate among poor children. These findings provide a partial explanation for why Medicaid-eligible children in poverty remain uninsured. While my first chapter focuses on traditional means-tested public health insurance which targets mainly low income families, the second chapter explores the issues with a more recent intervention that extends beyond low income families. In recent years, several states have allowed young adults as old as 30 to remain covered under their parents' employer-provided health insurance. For those who qualify for these benefits, the expansion of parental coverage partially reduces the value of being employed by a firm that provides health insurance since adult children can now get health insurance through another channel. We employ quasi-experimental variation in the timing and generosity of states' eligibility rules to identify the effect of the policy change on young adults' labor market choices. Our results suggest that the expansion of parental coverage increases the group coverage rate and reduces labor supply among young adults, particularly in full-time employment. The third chapter analyzes the effect of educational tracking by decomposing it into the separate roles of peer effects and coursework. The practice of tracking often results not only in grouping students by different ability, but also in providing different types of coursework for students. For instance, the advanced track may have both higher achieving peers and higher level coursework. Using detailed panel data from the San Diego Unified School district, I find that having high achieving peer is beneficial, while I do not find convincing evidence that taking more advanced math coursework predicts student's test score