This dissertation consists of two chapters at the intersection of labor and the economics of education. In Chapter 1, I examine the role of management in the public sector, focusing on school principals and how they impact student outcomes. I find that a one standard-deviation increase in principal quality raises average student achievement by about 5% of a standard-deviation corresponding to a $15,000 increase in expected lifetime earnings. To identify effective principals, I construct principal value-added estimates and provide the first evidence that they are forecast unbiased. I use these individual-level estimates to examine the correlates of value-added and the mechanisms through which principal effects operate. I find that test-score boosting principals are stronger at recruiting and retaining their strongest staff members, even though they cannot offer teachers higher salaries, and are more likely to assign their best teachers to larger classrooms, increasing overall student learning. I argue that this finding reflects differences in soft skills and management practices as I document a robust positive relationship between value-added and various measures of leadership and teacher empowerment. In Chapter 2, I study how changes in job security affect worker selection and effort in the context of tenure removal for public school teachers. My analysis reveals that in the years after North Carolina eliminated tenure, newly hired teachers had smaller effects on student math and reading achievement as measured by value-added. These effects are driven by selection into the workforce, as teacher observable characteristics remained largely unchanged. Additionally, I find that tenure receipt is not associated with changes in effort, as value-added in the years after tenure parallels the pre-tenure years. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]