In this dissertation, I examine various factors shaping students' trajectories and opportunities later in life. In Chapter 1, I explore the role of grade retention policies. Grade retention as a remedial policy is controversial because the benefits of extra instruction time may not outweigh its costs. Previous research has primarily examined retention for specific grades. By exploiting plausibly exogenous variation in retention generated by a nationwide promotion policy in Chile, I demonstrate that retention timing is critical in determining its effect on academic performance and access to higher education. Being held back only reduces the probability of future grade retention for young primary students. Additionally, older primary students are less likely to return to school the following academic year or graduate from high school. High school grade-retained students are the most affected, with a 10-20 percentage point reduction in their likelihood of high school graduation, and many switch to adult education in response to retention. Interestingly, even though high school students who are held back are just as likely to take the college admission test, they show a positive 0.1 SD increase in Spanish and math performance. Then, in Chapter 2, I focus on the impact of massive and sudden school closures following the 2011 nationwide student strike in Chile on teenage pregnancy. We observe an average increase of 2.7% in teenage pregnancies in response to temporary high school shutdowns, equal to 1.9 additional pregnancies per lost school day. The effect diminishes after three quarters since the strike's onset. The effects are predominantly driven by first-time mothers aligned with high-school absenteeism periods and are unrelated to the typical seasonality of teenage fertility or pregnancies in other age groups. Additionally, we document that the strike had a more prominent disruptive role by affecting students' educational trajectories, evidenced by a persistent increase in dropout rates and a reduction in college admission test take-up for both female and male students. Lastly, in Chapter 3, I explore inequalities in performance associated with the school type students attend, particularly the contribution of teachers to student performance in Chile's college admission test (PSU). Our analysis is based on a unique teacher-student matched dataset and decomposition methods. The findings suggest that teachers' performance on the PSU and the characteristics of their educational degrees are significant predictors of students' success. When controlling for students' and predetermined school characteristics, the gap between voucher and public schools is reduced. Productivity differences emerge as key factors driving the disparities across school types. The analysis underscores the crucial role of teacher-student interactions in shaping student outcomes. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]