This dissertation contains three essays attempting to further our understanding of key questions in applied health and behavioral economics. Chapter 1 empirically explores the role of uncertainty in beliefs on individuals’ medical decisions in the setting of breast cancer risks and mammograms. In an online survey for women over the age of 35 conducted on Prolific, we leverage an information treatment of individuals’ personalized predicted breast cancer risk as an exogenous shock to manipulate their certainty in beliefs. We document that participants are uncertain about their breast cancer risks, the information treatment significantly reduces the gap between their beliefs and their predicted cancer risk, and the information treatment effectively manipulates certainty in beliefs. However, we did not find the information treatment has a significant effect on participants’ mammogram decisions. Chapter 2 ascertains the reasons that motivated students to resort to a pass/fail grade option both before and after university closures due to COVID19 in Spring 2020 with administrative data from an Ivy League university in northeastern United States. We use a generalized difference-in-difference estimation strategy to as- certain the role of a student-specific return-home treatment – measured by home address distance from campus and home community internet coverage – as potential barriers to learning. We find that the “return-home” treatment had a significant effect on students’ decisions to switch the grading option to S/U. We also show that the rest of the story is nuanced, by offering a battery of non-causal but informative correlates, which show that revealed preference for the graded option is associated with class size, student seniority, gender, majors, and peer group support from students of the same gender and ethnicity in the same class even when students are physically apart. Chapter 3 tests whether Employer Mandate of the Affordable Care Act significantly affects employees’ take-up of employer health insurance and their utilization of healthcare services. This paper finds that the reform has a significant effect in increasing employers’ employer sponsored health insurance offering, but limited effect transfers to employees to increase their employer sponsored health insurance take-up. In addition, this paper finds the reform has limited effect in changing people’s healthcare utilization pattern and their satisfaction towards the healthcare services they receive. The paper also finds evidence that employers transfer the cost of providing more employer sponsored health insurance of more generous coverage to employees through lower wages.