Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Economics, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Vita. / Bibliography: leaves 320-327. / by Axel Boersch-Supan. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 1993. / Includes bibliographical references. / by Sara Fisher Ellison. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2005. / Includes bibliographical references. / This dissertation is a collection of three independent essays in empirical development economics using data from China. In the first two chapters, I examine the determinants of choices within the household. In the first chapter, I estimate the causal effects of total income, relative female and relative male income on sex imbalance. The second chapter studies the effects of relaxations in the One Child Policy on sex ratios and family size and then exploits the exogenous variation in family size caused by the relaxations to estimate the causal effect of family size on school enrollment. The third chapter is a descriptive study of income inequality for top income earners in China during 1986-2002 and the potential redistributive effectiveness of progressive income taxation. / by Nancy Qian. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 1993. / Includes bibliographical references (leaves 85-86). / by Jonathan Erik Jacobson. / Ph.D.

Massachusetts Institute of Technology. Dept. of Economics. Thesis. 1973. Ph.D. / MICROFICHE COPY ALSO AVAILABLE IN DEWEY LIBRARY. / Vita. / Includes bibliographies. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2010. / "June 2010." Cataloged from PDF version of thesis. / Includes bibliographical references (p. 235-244). / This thesis consists of four essays about "uncertainty" and how markets deal with it. Uncertainty is about subjective beliefs, and thus it often comes with heterogeneous beliefs that may be present temporarily or even forever. The first essay analyzes the effect of uncertainty, and the associated belief heterogeneity, on financial contracts and asset prices. I assume that optimists have limited wealth and take on leverage in order to take positions in line with their beliefs. To have a significant effect on asset prices, they need to borrow from traders with moderate beliefs using loans collateralized by the asset itself. Since moderate lenders do not value the collateral as much as optimists do, they are reluctant to lend, which provides an endogenous constraint on optimists' ability to leverage and to influence asset prices. I demonstrate that optimism is asymmetrically disciplined by this constraint, in the sense that optimism concerning the likelihood of bad events has no or little effect on asset prices, while optimism concerning the relative likelihood of good events could have significant effects. This result emphasizes that what investors disagree about matters for asset prices, to a greater extent than the level of disagreement. New financial assets are often associated with much uncertainty and belief heterogeneity, especially because they do not have a long track record. While the traditional view of financial innovation emphasizes the risk sharing role of new assets, belief heterogeneity about these assets naturally leads to speculation, which represents a powerful economic force in the opposite direction. The second essay analyzes the effect of financial innovation on the allocation of risks when both the risk sharing and the speculation forces are present. I demonstrate that speculation on new assets is amplified by the hedge-more/bet-more effect: Traders make bets on new assets which they then hedge by taking complementary positions on existing assets, which in turn enables them to place larger bets and take on greater risks. This effect suggests that, as asset markets get more complete, they become more susceptible to speculation and further financial innovation is more likely to be destabilizing. The third essay, joint with Ricardo Caballero, concerns the sources of uncertainty. We present a model in which uncertainty suddenly and endogenously rises in response to an increase in the complexity of the economic environment. In our model, banks normally collect information about their trading partners which assures them of the soundness of these relationships. However, when acute financial distress emerges in parts of the financial network, it is not enough to be informed about these partners, as it also becomes important to learn about the health of their trading partners. As conditions continue to deteriorate, banks must / (cont.) learn about the health of the trading partners of the trading partners of the trading partners, and so on. At some point, the cost of information gathering becomes too unmanageable for banks, uncertainty spikes, and they have no option but to withdraw from loan commitments and illiquid positions. A flight-to-quality ensues, and the financial crisis spreads. The fourth essay, joint with Daron Acemoglu, analyzes the effect of uncertainty of a special kind, that involves economic agents' private actions and anonymous market transactions, on the functioning and efficiency of competitive markets. Despite a sizeable literature, how competitive markets deal with this type of uncertainty remains unclear. A "folk theorem" originating, among others, in the work of Stiglitz maintains that competitive equilibria are always or "generically" inefficient (unless contracts directly specify consumption levels as in Prescott and Townsend, thus bypassing trading in anonymous markets). This essay critically reevaluates these claims in the context of a general equilibrium economy with moral hazard. Our results delineate a range of benchmark situations in which equilibria have very strong optimality properties. They also suggest that considerable care is necessary in invoking the folk theorem about the inefficiency of competitive equilibria with private information. / by Alp Simsek. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Economics, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 109-115). / This dissertation combines three essays on the economics of education. The essays share a common focus on comparing experimental and non-experimental econometric methods. I present findings from randomized evaluations of two prominent education interventions for low-income students. In the spirit of LaLonde's (1986) pioneering re-analysis of experimental evidence on federal job training programs, I leverage the experimental data to assess nonexperimental methods for evaluating program impacts. The first chapter - written jointly with Joshua Angrist, David Autor, and Amanda Pallais - reports early results from a randomized evaluation of the Susan Thompson Buffett Foundation (STBF) scholarship, a large, privately-funded financial aid program for applicants to Nebraska's public colleges. Randomly-assigned scholarship offers boosted average grants received by $6,300 per year and dramatically improved enrollment and retention, especially for groups with historically-low persistence rates. Four years after award receipt, nonwhite students and first-generation college goers were nearly 20 percentage points more likely to be enrolled in college. Awards generated similarly large gains for students with the weakest high school GPAs in the eligible applicant pool. Over time, scholarships shifted many students from two- to four-year colleges, reducing associate's degree completion in the process. The economic returns to scholarship support will therefore likely hinge on whether award winners convert their extended enrollment into bachelor's degrees. The oldest study cohort will record its four-year graduation rate in the summer of 2016, but many students will likely take five or more years to finish. A complete picture of award impacts on degree receipt may therefore still be several years away. In the second chapter, I assess how selection bias distorts non-experimental estimates of STBF scholarship impacts. I show that observed gaps in retention rates between scholarship winners and rejected applicants overstate the causal effect of scholarships on dropout by nearly double. Controlling for high school GPA and Expected Family Contribution (EFC) - two widely-used criteria for awarding merit aid - explains roughly half the gap between the experimental benchmarks and observed enrollment rates. Conditional on GPA and EFC, however, additional demographic traits like race, gender, and parental education have little explanatory power. Thus, scholarship winners are positively selected on potential enrollment in the absence of treatment, and a variety of observational estimation strategies overstate the causal impacts of scholarships on enrollment and retention. Among the replication strategies, Kline's (2011) Oaxaca-Blinder procedure outperforms both discrete covariate matching and propensity score weighting on bias and precision. Because STBF award effects are larger for students who are less likely to win scholarships, linear regression estimates are even bigger than the biased estimates of treatment on treated (TOT) effects. In the final chapter, I use experimental estimates of Teach for America's (TFA) impacts on student achievement to validate a non-experimental strategy for measuring the long-run effects of hiring TFA teachers. Randomized evaluations show that TFA teachers outperform colleagues in boosting achievement at hard-to-staff schools. Despite this cross-sectional evidence, TFA's long-run effects remain unknown, a key concern for policymakers. High turnover among TFA recruits - who commit to serve for just two years - may undercut the long-run returns to hiring non-TFA teachers, who improve steeply with experience. To assess this potential tradeoff, I measure the short- and long-run effects of TFA hiring in North Carolina, where schools have employed TFA teachers since the program's founding in 1990. I identify TFA hiring effects by exploiting quasi-random variation in teacher hiring shocks across grades within schools. In the short run, TFA rookies increase math scores markedly relative to the non-TFA teachers schools might otherwise hire; TFA's initial advantage in reading is modest. When schools replace exiting TFA teachers with new TFA recruits, these gains more than offset the costs of lost experience, increasing long-run achievement. On the other hand, when TFA supply fluctuates, schools may have to replace exiting TFA teachers with inexperienced and lower-performing non-TFA hires. On net, short run achievement gains from one-shot TFA hiring still exceed the costs. JEL Classification: C93, I22, J63. / by Sally Lindquist Hudson. / joint work with Joshua Angrist, David Autor, and Amanda Pallais -- Early results from a randomized evaluation of post-secondary aid / Selection bias in observational estimates of financial aid impacts -- The dynamic effects of teach for America in hard-to-staff schools. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 1996. / Includes bibliographical references. / by David H.L. Reiley. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Economics, 2000. / Includes bibliographical references. / In 1991, a reform was passed changing the rules for social security for rural workers in Brazil. The reform consisted of a reduction in the minimum eligibility age for old-age benefits, an extension of benefit eligibility to workers who are not the heads of their households, and an increase in the minimum value for benefits. As a consequence, elderly rural workers and their households found a substantive increase in their non-labor incomes. Because old-age benefits for rural workers are not means or retirement tested, this reform may be a very useful natural experiment for studying pure income effects. I use information from surveys administered before and after the reform is implemented to identify the effects of the reform on the actual receipt of benefits by the elderly. The first chapter studies the labor supply of elderly rural males in response to the reform. I find that elasticities of labor supply with respect to benefits generosity among rural men age 60 to 64 are greater than those estimated from developed country data. I find that benefit take-up rates are greatest among the better educated, but that least-schooled workers have the largest elasticities of labor supply. I also find that husbands respond to wives' benefits by increasing their labor supply, perhaps because of bargaining considerations within the household. Last but not the least, I find that anticipated benefits do not affect the labor supply of workers close to the minimum eligibility age. The second chapter studies the choice of living arrangements of unmarried elderly females, that is never married, divorced or widowed females. The main finding is that living arrangements are responsive to benefits income: Brazilian rural elderly females value their privacy and independence, choosing not to coreside with their adult children if they can afford to do so. This result suggests that substituting the extended family for formal transfer programs by means of severe filial responsibility laws and scaling back of social security may be a very costly measure for the elderly in Brazil. Because the estimates of this paper are based on the behavioral response of unmarried elderly females in the rural areas, one may reasonably argue that those effects are underestimates of the effects for the whole sample of elderly, males and females, married or unmarried, residing in rural or urban areas. The final chapter studies the effects of increases in non-labor income at the household level on children's outcomes, particularly labor participation and school enrollment. In this chapter I study the impact of this increase in non-labor income on children of ages 10-14 living in the same household as old-age beneficiaries. Counterfactual analysis based on reduced form estimates implies that little less than 20% of the gap between 100% enrollment and counterfactual enrollment rates was closed for girls living with at least an elderly who benefited from the reform, with a smaller effect for boys. Labor force participation of boys also seem to have been effected by the reform, with a reduction in participation rate around one-tenth of counterfactual participation rates. Those results may be underestimates of the effects of overall income growth because economy-wide increases in income are likely to be associated with shifts in social norms and attitudes towards children's labor participation and schooling. / by Irineu E. Carvalho. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Economics, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 131-136). / This thesis consists of three chapters on the economics of pain management, focusing on the effects of public policies that reduce availability of opioid pain relievers. In each of the three chapters, I exploit state-level variation in the introduction of Prescription Monitoring Program (PMP) laws as a source of plausibly exogenous variation in availability of prescription opioids. I employ several rich data sources, including individual-level administrative medical claims data linked to work absences and disability experience, and National Vital Statistics System mortality data, to investigate a series of questions regarding the optimal regulation of opioid pain relievers. In Chapter 1, I document important welfare tradeoffs in the regulation of prescription opioids. I find that prescribing restrictions achieve a key policy goal in reducing opioid overdose deaths by about 12%, but also find substantial costs, including increased pain in the hospital setting, more missed work days for injured and disabled workers, and increased total medical spending. A back-of-the-envelope welfare calculation suggests welfare losses and gains from regulation are on the same order of magnitude - approximately $12.1 billion per year in increased costs from inpatient and outpatient medical spending plus lost wages, compared to $7.3 billion per year in benefits from lives saved from opioid overdose. In Chapter 2, I consider illicit opioid and heroin abuse. I investigate the determinants of the nearly 40% year-on-year increase in heroin mortality since 2010, focusing on the relationship between prescription opioids and heroin, by decomposing demand- and supply-side effects of recent crackdowns on prescription opioids. I utilize a county-border strategy that tests for and then exploits cross-state spillovers from neighboring-state crackdowns. I find evidence that heroin is a short-run substitute and long-run complement for prescription opioids. Underlying this relationship are two opposing forces: a reduction in illicit opioid supply drives up use of heroin, but a reduction in medical provision of opioids reduces that demand in the long run. Finally, in Chapter 3, I apply machine learning techniques to study heterogeneous responses to prescribing restrictions, identifying, characterizing, and studying more closely the marginal patients who lose access to prescription opioids after PMP introduction. / by Angela E. Kilby. / Ph. D.