This dissertation studies the reasons for and consequences of different choices in human capital investment. The theme connecting the three essays is a desire to understand reasons for inequality in educational choices and outcomes, as well as shed light on policies that may or may not remedy those inequalities. In each chapter, I use quantitative casual inference methods and rich administrative data to understand students' educational trajectories. The first chapter investigates the role of beliefs about academic performance in explaining gender differences in college major choice. I run a randomized controlled trial with undergraduate students across seven STEM disciplines. Treated students receive information about their performance rel...