Advisors: Virginia Wilcox.Committee members: Jeremy Groves; Maria Ponomareva.Includes bibliographical references.Includes illustrations.This dissertation constitutes three separate essays in health economics. The first essay examines whether Medicare Part D led to changes in the health behaviors that are essential to manage chronic diseases. Using data from the Medical Expenditure Panel Survey, I find that the implementation of Medicare Part D reduces the probability of engaging in physical exercise. The effect on dieting is inconsistent across different specifications and the effect on cigarette smoking is not statistically significant. The negative physical exercise effect of Medicare Part D is more pronounced among patients with low educ...