This thesis aims to identify causal effects using a natural experimental approach. We focus on the Great Hanshin-Awaji Earthquake in midwestern Japan as a source of exogenous variation in the variables of interest. Chapter 1 explores the causal effect of schooling on juvenile delinquency using variation in schooling caused by policy interventions in specific municipalities after the earthquake. Using the instrumental variable estimator to address endogeneity problems arising from simultaneity and unobserved heterogeneity, we find that schooling reduces juvenile delinquency, although some of our estimates have large standard errors and are imprecisely estimated. The results indicate that a one-percentage-point increase in the high school participation rate reduces the number of juvenile arrests by approximately 1.1 per 1,000 youths. 1 Estimates of social benefits show that it is less expensive to reach a target level of social benefits by improving schooling than by strengthening police forces. Chapter 2 studies the causal effect of volunteer work on the mortality of the elderly. After the earthquake, levels of volunteering increased considerably in municipalities hit by the earthquake, while other municipalities did not experience such a sharp increase. This exogenous shift in levels of volunteering is exploited to address the endogeneity problem associated with estimating the effects of volunteering. Specifically, unobserved heterogeneity across municipalities that affects both morality and the level of volunteering, such as the quality of local health care services, may bias estimates on the effect of volunteering. The results indicate that volunteering has no significant effect on mortality amongst people in their 50s and 60s, while it significantly reduces mortality amongst people in their 70s and 80s or older. Evaluated at the mean, the estimate implies that the life of approximately one person aged 80 or older (out of 186 persons) is saved in a given year when the number of volunteers increases by 100 (out of 1,911 persons).
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:572916 |
| Date | January 2012 |
| Creators | Aoki, Yu |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/54351/ |
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