Postsecondary education in the United States has played an increasingly more important role over time. In fact, in just a few decades, the share of recent high school completers who enroll in college each year has grown from 51% in 1975 to 70% in 2016 (Snyder, de Brey, & Dillow, 2019, p. 395). However, only 58% of entering college students earn their first postsecondary degree or certificate within six years (National Student Clearinghouse Research Center, 2018). The importance and challenge of obtaining a college education has not gone unnoticed by education policymakers, whose focus on postsecondary educational outcomes of public schools (K-12) has increased, as evidenced by the Common Core State Standards, initiated in 2009 and currently adopted by 41 states, and the Every Students Succeed Act (ESSA) of 2015, both of which emphasize college and career readiness (Malin, Bragg, & Hackmann, 2017). Given the increasing importance of postsecondary education, it is worth asking what improves student outcomes in this sector. The studies that make up this dissertation attempt to address and answer this question by focusing on selected public school and postsecondary educational policies and practices and their relationships to postsecondary enrollment, graduation, field of study, psychosocial outcomes, and job earnings. This work is among the first of its kind to examine the relationship between public school accountability policies and postsecondary outcomes using data from across all 50 states. In doing so, this dissertation helps to expand the shorter-term academic outcomes traditionally considered in evaluations of accountability policies and practices to longer-term academic and non-academic outcomes. To evaluate these outcomes, the longitudinal data and approaches taken demonstrate the methods (and their limitations) that can be used in evaluations of long-term educational outcomes. The first two papers, "College Enrollment and No Child Left Behind-Era School Accountability" and "The Relationship of Prior Exposure to School Accountability Policies to Postsecondary Educational and Employment Outcomes," consider school accountability policies under the No Child Left Behind Act (NCLB) of 2001 and similar policies that states enacted earlier (Dee & Jacob, 2011; Hanushek & Ramond, 2005). These policies were partly a reaction to "A Nation at Risk: The Imperative for Educational Reform" in Education, which described a decline in the relative academic performance of the nations' high school students that threatened to undermine the competitiveness of the nation's workforce. Departing from past policy focused on ensuring adequate school inputs, emerging state and federal policies focused on improving school outputs by holding schools accountable for their students' outcomes. These new accountability policies introduced academic standards, standardized testing, consequences for school academic achievement, and increased competition through school choice (Fuhrman, 2004).Student scores, primarily on standardized tests in math and reading, played a central role among the school accountability policies that measured school performance (Figlio & Ladd, 2015; Figlio & Loeb, 2011). States required the publishing of school performance measures ("report cards") for view by the public and attached incentives and sanctions ("consequences") to the measures (Hanushek & Raymond, 2005). During the period leading up to NCLB, some states individually implemented these policies. In 2002, however, under NCLB, all states were required to do both: report school performance measures from math and reading standardized tests (for Grades 3-8 and for one high school grade 10, 11, or 12) and attach consequences to either meeting or failing to meet school performance measures. Negative consequences escalated in proportion to the degree that schools continued to perform poorly. Schools that underperformed were required to revise their curriculum, implement additional educational services (e.g., tutoring), allowed parents to choose a different school for their children, and were taken over by the state. Subsequently, in 2011, the U.S. Department of Education began granting states waivers from NCLB provisions due in part to the difficulty schools encountered in meeting the student proficiency targets stipulated by NCLB (Polikoff, McEachin, Wrabel, & Duque, 2014). Today, ESSA, which replaced NCLB, continues to require states to hold schools accountable for student outcomes but provides individual states more freedom in determining the outcomes assessed in their accountability systems and how to measure school performance on the outcomes. As mentioned, ESSA focuses on college and career readiness. Few studies, however, have evaluated how school accountability policies are related to college and career outcomes. The first two papers in this dissertation address this gap in the literature by providing additional evidence on the connection between K-12 school accountability policies and postsecondary outcomes. The two aforementioned papers leverage time-varying state implementations of school accountability policies in the 1990s and 2000s to estimate the relationship to postsecondary educational and earnings outcomes. The first paper concentrates on how the fraction of recent high school graduates from each state that enrolled in a postsecondary institution for the first time may have changed due to the implementation of school accountability policies. The paper uses aggregate institutional data from postsecondary institutions and state education agencies from across the 50 states and difference-in-differences regression models. The results suggest a very small negative impact on enrollments at 4-year institutions and private non-profit institutions. Estimates for enrollments at other institutional types are imprecise. The second paper studies college enrollment as well but also examines earning a bachelor's degree, majoring in a STEM field, and job earnings at ages 24-25. Using data from a longitudinal survey that followed individuals from birth and into adulthood, the study employs descriptive regression models of the relationship between cumulative years of exposure to state accountability policy in the K-12 years to these outcomes. Estimates obtained were not significant save for a negative relationship found between accountability exposure and earning a bachelor's degree. These two papers provide additional evidence on how school accountability policies may be related to postsecondary student outcomes. The third paper, "A Comprehensive College Transition Program and Nonprogram Peer and Faculty Interactions: An Application of Mediation Analysis," studies a comprehensive college transition program for new college students from low-income backgrounds at three university campuses. The program shares similar elements as first-year programs at many postsecondary institutions nationwide--programs that are designed to improve outcomes for students from challenging backgrounds. The paper examines how interactions with faculty and peers may mediate the psychosocial outcomes of mattering and sense of belonging to a campus. While these psychosocial outcomes are important in and of themselves, they are also related to academic outcomes. However, little rigorous statistical evidence on the best way a college program can bring about such outcomes exists. Using recently developed methods in mediation analysis, but heretofore rarely used in educational evaluations, this paper explores the potential for campus interactions encouraged by the program to explain differences in mattering and sense of belonging. In applying mediation analyses, the study notes the many assumptions needed to establish unbiased estimates of mediation effects. After performing sensitivity analyses and weakening a key assumption, the study finds no evidence that faculty and peer interactions mediate the psychosocial outcomes studied. The study does find, however, that the program substantially increased interactions with faculty and that peer interactions are relatively more strongly related to the two psychosocial outcomes studied. In obtaining these results, this paper brings new attention to the use of mediation analysis in evaluating postsecondary educational programs. These three papers contribute to a better understanding of postsecondary outcomes by considering how they are related to prior schooling policies and potential mediators. In so doing, these studies can inform future evaluations of school and postsecondary policies and practices. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. 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