About 75% of U.S.-trained, non-citizen PhDs in science and engineering work in the U.S. after graduation, and 54% of those who stay take postdoctoral positions. The probability of postdoctoral participation is substantially higher for temporary visa holders than for permanent visa holders because of visa-related restrictions in the U.S. labor market. To identify the causal effects of visa status on entry into a postdoctoral position, the first chapter uses a unique shock to visa status generated by the Chinese Student Protection Act of 1992. I use eligibility for the act as an instrumental variable for visa status. 2SLS estimates show that permanent visa holders are 24% less likely to take postdoctoral positions than temporary visa holders. This sudden removal of visa restrictions reduces labor supply in the postdoctoral sector and increases supply in the non-postdoctoral sector, which may affect relative wages across sectors. Using data from the Survey of Doctorate Recipients in the 1990s, the second chapter shows that a one percentage point decrease in the percentage of temporary immigrants among new PhDs increases the relative wage of native postdocs to non-postdocs by between 0.9% and 2%. This effect operates through increasing wage level of native postdocs. I also find that natives do not change their postdoctoral participation in response to this supply shock. The third chapter examines how differences in school resources impact student performance. Using unique administrative data collected in one Chinese city, I estimate the effect of attending a magnet high school on academic performances. To separate the effect of school resources from abilities of students, I exploit the regression discontinuity generated by thresholds for entering a magnet school in China's High School Entrance Exam. These thresholds create a significant difference in the cost of attending a magnet school, which in turn generates a discontinuity in the probability of attending such schools. I find that attending a magnet school does not affect students' academic performances in any subject, in both the low-stake annual City Exam and the high-stake National College Entrance Exam. [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.]