Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 127-132). / Chapter 1 examines geographic variations in physician practice styles by exploring the role of physician-specific factors such as preferences and learned behavior versus environment-level factors such as hospital capacity. I exploit cardiologist migration across geographic regions and find that physicians who start off in the same region and subsequently move to dissimilar regions practice similarly before the move but very differently after the move. Based on this change in behavior, baseline estimates imply that the role of the environment on physician behavior is twice as important as physician-specific factors. Specifically, a one percentage point change in practice environment results in an immediate 2/3 percentage point change in physician behavior, with no further changes over time. Chapter 2 (co-authored with Leila Agha) explores the diffusion of new cancer drugs by testing the influence of physician investigators who lead clinical trials. The basic idea is to exploit variation across drugs in the location of clinical trials to test whether geographic proximity to a principal investigator influences the speed of technology adoption. Using original data on clinical trial study authors and sites for 21 new cancer drugs along with Medicare claims data from 1998-2008, we estimate that patients are 30% more likely to receive treatment with a new drug if they seek care in the hospital referral region where the drug's principal investigator practices. This effect, which is estimated in the first two years following initial FDA approval, fades over time until there is no apparent difference in utilization after four years. Chapter 3 (co-authored with Leila Agha) explores the prescribing of new cancer drugs for off-label (non-FDA approved) indications, yielding three key results. First, over 20% of new cancer drug use within the Medicare population over 1998-2008 was applied to off-label cancers. Second, geographic proximity to the principal investigator of a drug's pivotal clinical trial-a factor which appears to significantly boost on-label usage-has no discernible impact on off-label prescribing. Third, we find that prescribing increases following FDA approval expansions, suggesting that approval status influences patient treatment and thus may provide a useful policy instrument for directing medical technology adoption. / by David Paul Molitor. / Ph.D.

Massachusetts Institute of Technology. Dept. of Economics. Thesis. 1967. Ph.D. / Vita. / Bibliography: leaves 292-304. / by Scott McNeil Eddie. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Economics, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 78-81). / This thesis consists of three empirical contributions to the applied microeconomics literature. The first chapter shows that there is substantial geographical variation in the use of cesarean sections in Italy. Such variation is not driven by medical need and higher cesarean rates are achieved by performing the procedure on less and less appropriate patients. I find no evidence that high-use areas develop higher ability in performing cesareans. Finally, by using both panel data analysis and instrumental variables, I show that there is no significant relation between risk-adjusted cesarean rates and maternal and neonatal mortality. The combined evidence in this chapter suggests that lowering cesarean rates would likely affect less appropriate patients, would not have negative spillovers in terms of quality of the procedure and would not affect neonatal nor maternal mortality. The second chapter studies the response of sickness absences to changes in the replacement rate for sick leave. In June 2008 a national law modified both the strength of monitoring and the monetary cost of sick leaves for public sector employees. Using administrative data I show that absenteeism largely decreased following the reform. I identify the effects of an increase in the monetary cost of an absence using a differences in differences strategy that exploits variation in changes to the replacement rate for sick leave. Under the assumption that changes in monitoring had the same proportional impact on absenteeism within the same institutions, I estimate that a 1 percentage point decrease in the replacement rate reduces absenteeism by The last chapter investigates the effect of diffusion of organized crime on local economies by examining a legal institution that operated in Italy between 1956 and 1988. The law allowed Public Authorities to force mafiosos to resettle to another town. Using variation in the number of resettled mafia members across destination provinces in a differences-in-differences setting, I find no conclusive evidence on the effect of the policy on crime or homicides, while there is a very robust positive impact on employment in the construction sector. This result is consistent with mafia exploiting these new locations mainly for money laundering and corruption. / by Annalisa Scognamiglio. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2002. / Includes bibliographical references. / The first essay finds that the market betas of value and small stocks have decreased by about 75% in the second half of the twentieth century. The decline in beta can be related to a long-term improvement in economic conditions that made these companies less risky. The failure to account for time-series variation of beta in unconditional CAPM regressions can explain as much as 30% of the value premium. In some samples, about 80% of the value premium can be explained by assuming that investors tied their expectations of the riskiness of these stocks to the high values of beta prevailing in the early years. Moving from these findings, the second essay (co-authored with Tobias Adrian) explores in detail the relation between the 'value premium' and the decrease in value stocks' beta. We develop an equilibrium model of learning on time-varying risk factor loadings. In the model the CAPM holds from investors' ex-ante perspective. However, the econometrician can observe positive mispricing, whenever the expected beta is above the true level. Given the finding of a decreasing beta, it is likely that investors' expectation of the beta of these stocks has been above the actual level. Therefore, our model can provide an explanation for the 'value premium'. We present the results of simulations in which the model accounts for up to 80% of the 'value premium' in the 1963-2000 sample. / (cont.) The third essay analyzes the response of stock returns to earnings information. First, I test the assumption that market expectations of earnings reflect a seasonal random walk, despite the actual process being autoregressive. This hypothesis is rejected. Second, I test the opposite view that expectations are unbiased. The data rejects this possibility for small firms. On the other hand, large firms' prices provide evidence of efficiency. Finally, I show that in the case of small firms the market understates the autoregression coefficient in the earnings process, and it incorrectly assumes that this coefficient is positive, even when actual earnings are seasonal random walks. / by Francesco Franzoni. / Ph.D.

Massachusetts Institute of Technology. Dept. of Economics. Thesis. 1967. Ph.D. / Page number 282 used twice; 16 unnumbered pages inserted; lacking l. 249, 362. Vita. / Bibliography: leaves 300-312. / by Robert J. Gordon. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 1992. / Includes bibliographical references (leaves 216-217). / by Persio Arida. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 173-180). / This dissertation consists of three essays covering topics in the economics of education. Two common threads connect these essays: first, a focus on the inputs and practices driving variation in effectiveness across educational programs; and second, an interest in the relationships between students' preferences, characteristics, and returns to human capital investment. In the first chapter, I develop and estimate a structural model of school choice that links students' decisions to apply to and attend charter schools in Boston, Massachusetts to their potential achievement test scores in charter schools and public schools. This chapter is motivated by a growing literature that uses randomized entrance lotteries to show that urban charter schools, including those in Boston, substantially increase test scores and close racial achievement gaps among their applicants. A key policy question is whether charter expansion is likely to produce similar effects on a larger scale. To address this question, I use the structural model to predict the effects of charter expansion for the citywide achievement distribution in Boston. Estimates of the model suggest that charter applicants are negatively selected on achievement gains: low-income students and students with low prior achievement gain the most from charter attendance, but are unlikely to apply to charter schools. This form of selection implies that lottery-based estimates understate gains for broader groups of students, and that charter schools will produce substantial gains for marginal applicants drawn in by expansion. Simulations suggest that realistic expansions are likely to reduce the gap in math scores between Boston and the rest of Massachusetts by up to 8 percent, and reduce racial achievement gaps by roughly 5 percent. Nevertheless, the estimates also imply that perceived application costs are high and that most students prefer traditional public schools to charter schools, so large expansions may leave many charter seats empty. These results suggest that in the absence of significant behavioral or institutional changes, the potential gains from charter expansion may be limited as much by demand as by supply. The second chapter, written jointly with Joshua Angrist and Parag Pathak, seeks to explain differences in effectiveness across charter schools. Using a large sample of lotteried applicants to charter schools throughout Massachusetts, we show that urban charter schools boost student achievement, while charter schools in other settings do not. We then explore student-level and school-level explanations for this difference. In an econometric framework that isolates sources of charter effect heterogeneity, we show that urban charter schools boost achievement well beyond that of urban public school students, while non-urban charters reduce achievement from a higher baseline. Student demographics explain some of these gains since urban charters are most effective for non-whites and low-baseline achievers. At the same time, non-urban charter schools are uniformly ineffective. Our estimates also reveal important school-level heterogeneity within the urban charter sample. A non-lottery analysis suggests that urban charters with binding, well-documented admissions lotteries generate larger score gains than under-subscribed urban charter schools with poor lottery records. Using a detailed survey of school practices and characteristics, we link charter impacts to inputs such as instructional time, classroom techniques and school philosophy. The relative effectiveness of urban lottery-sample charters is accounted for by these schools' embrace of the No Excuses approach to urban education, a package of policies that includes strict discipline, increased instructional time, selective teacher-hiring, and a focus on traditional skills. In the third chapter, I use data from the Head Start Impact Study (HSIS), a nationwide randomized trial of the Head Start program, to study the relationship between site-level treatment effects and educational inputs within Head Start. Studies of small-scale, intensive early-childhood programs, including the High/Scope Perry Preschool Project, show that such programs can have transformative effects on human capital and economic outcomes. Evidence for larger-scale programs like Head Start is more mixed. I use the HSIS data to ask whether Head Start centers using practices more similar to successful model programs produce larger short-run effects on cognitive and non-cognitive skills. My results show that while there is significant variation in effectiveness across Head Start centers, centers that are more similar to the Perry Preschool Project on observed dimensions are not more effective. Specifically, Head Start centers using the High/Scope curriculum, the centerpiece of the Perry experiment, do not produce larger gains relative to other centers. Other inputs often cited as essential to the success of the Perry Project, including teacher education, teacher certification, teacher/student ratios, instructional time, and frequency of home visiting, are also unrelated to effectiveness in Head Start. These results suggest that replicating the success of small-scale programs may be difficult, as the effectiveness of such programs may be due to idiosyncratic, unmeasured inputs. JEL Classification: 121, C51, J24 / by Christopher Ross Walters. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2009. / Includes bibliographical references. / This dissertation contributes to an understanding of the manner in which various dimensions of malpractice law shape physician behavior and how this behavior, in turn, impacts health outcomes. In Chapter 1, I explore the association between regional variations in physician practices and the geographical scope of the standards of care to which physicians are held in malpractice actions. To investigate this general association, I explore whether treatment utilization rates in a state converge towards national utilization levels as states abandon the use of "locality rules" to adopt laws requiring physicians to comply with national standards of care. I focus the analysis on the case of cesarean delivery and find robust evidence of convergence in cesarean section utilization, whereby as much as 40 - 60% of the gap between state and national cesarean rates is closed upon the abandonment of a locality rule. In Chapter 2, I estimate the returns to regional cesarean intensities, drawing on an arguably exogenous source of variation in cesarean rates resulting from the adoption of national-standard laws. I first document robust evidence of triage in regional cesarean utilization, whereby physicians in high intensity regions begin to perform cesareans on mothers who are less in need of this intensive delivery alternative. Second, I find no evidence to suggest that an increase in regional cesarean rates otherwise leads to an increase in average neonatal outcomes. / (cont.) Third, I find evidence suggesting that increases in regional cesarean rates may be crowding out mothers otherwise in need of cesarean delivery. In Chapter 3, I consider another dimension to malpractice law and estimate the relationship between different levels of malpractice pressure, as identified by the adoption of non-economic damage caps and related malpractice laws, and certain decisions faced by obstetricians during the delivery of a child. Contrary to the conventional wisdom, I find no evidence to support the claim that malpractice pressure induces physicians to perform a substantially greater number of cesarean sections. However, I do find evidence of positive defensive behavior in the utilization of episiotomies during vaginal deliveries and in the durations of maternal lengths of stay. / by Michael D. Frakes. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Economics, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 107-114). / This thesis consists of three chapters about the spatial aspects of macroeconomics. Chapter 1 argues that local labor demand shocks are amplified by migration. I document that within-U.S. migration causes a large reduction in the unemployment rate of the receiving city, over several years. To establish the causal effect of inmigration, I construct a plausibly exogenous shock by using the outmigration of other places and predicting its destination based on historical patterns. Next, I document that the increase in the demand for housing explains the boom, through two channels. The construction channel occurs because housing is a durable good: hence there is a surge in the number of new houses and construction jobs. The house price channel occurs because the migrants' housing demand drives up prices, leading to increased borrowing and higher non-tradable labor demand. Last, I estimate that these effects imply that endogenous migration amplifies other shocks by 20 percent. Chapter 2, which is joint with Jack Liebersohn, estimates that between 20 and 40 percent of the overall rise in real house prices during the 2000-2006 U.S. housing boom can be attributed to an increase in the relative desirability of inelastic-housing-supply areas. First, we show local housing demand is significantly driven by population changes and changing relative desirability. We develop a theory for why an increase in the relative desirability of inelastic areas would raise house prices nationally. Finally, we quantify the total effect by creating a new measure of housing supply elasticity that covers the entire United States. We show that the decline in manufacturing and the fall in interest rates both played an important role through this geography channel. Chapter 3 documents that shifts in the geographic distribution of economic activity are more frequent around recessions. This effect is more pronounced in professions with greater nominal wage rigidity. As a possible explanation, I develop a new mechanism for equilibrium switching during recessions in a model of agglomeration using downwardly sticky wages. In a dynamic setting, the model requires a sufficiently large shock to switch equilibria. Within the model, place-specific time-specific firm subsidies can be welfare enhancing. / by Gregory Howard. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 1994. / Includes bibliographical references (leaves 129-136). / by Guy Debelle. / Ph.D.