This dissertation consists of three chapters. The first chapter examines the marriage premium with recent demographic changes in South Korea and the following two chapters address the signaling in the teacher labor market. In light of current and anticipated shifts in demographic factors that alarm the Korean society with decreasing marriage rate and fertility rate, understanding how the incentives of marriage respond to demographic changes is likely to be increasingly important in setting policies to resolve demographic catastrophe. Similarly, understanding the impact of pre-hire measures for job applicants in the labor market is also an important issue in reducing the social cost of screening. I seek to address questions in both of these areas using empirical approaches.