Does it matter who responded to the survey? Trends in the U.S. gender earnings gap revisited

Blau and Kahn (JOLE, 1997; ILRR, 2006) decomposed trends in the U.S. gender earnings gap into observable and unobservable components using the PSID. They found that the unobservable part contributed significantly not only to the rapidly shrinking earnings gap in the 1980s, but also to the slowing-down of the convergence in the 1990s. In this paper, we extend their framework to consider measurement error due to the use of proxy/representative respondents. First, we document a strong trend of changing gender composition of household-representative respondents toward more females. Second, we estimate the impact of the changing gender composition on Blau and Kahn's decomposition. We find that a non-ignorable portion of changes in the gender gap could be attributed to changes in the self/proxy respondent composition. Specifically, the actual reduction in the gender gap can be smaller than what the estimates without taking into account the measurement error might suggest. We conclude that a careful validation study would be necessary to ascertain the magnitude of the spurious measurement error effects.

The ART of Life: IVF or Child Adoption?

This paper analyzes the effects of child adoption on the utilization of assisted reproductive technology (ART) in the US. Using state-level longitudinal data for 1999-2006, we show that ART use is responsive to changes in adoption markets. Controlling for state-specific fixed effects, the estimated elasticity of ART cycles performed with respect to child adoptions is about -0.13 to -0.15. The responsiveness is higher when we consider infant adoptions, adoptions by older women, and international adoptions while there is no substitutability between ART and adoption of related children. Our findings suggest that public policies regarding adoption, including subsidies, influence ART use.child adoption, infertility treatment, assisted reproductive technology (ART), in vitro fertilization (IVF)

Keeping Up With Fashion: Recent Trends in the Subfields of Study of Doctoral Students in Economics

We conduct an analysis of recent trends on the subfields of study that doctoral students in economics choose for their dissertations. By investigating data on the JEL classification codes of dissertations reported by the Journal of Economic Literature from 1991 to 2007, we find that the trends in the subfields of study of doctoral dissertations follow those of articles published at five major general-interest journals (American Economic Review, Quarterly Journal of Economics, Journal of Political Economy, Review of Economic Studies, and Review of Economics and Statistics). In particular, the co-movement pattern is salient in subfields such as Microeconomics (D), Health, Education, and Welfare (I), and Economic Development and Growth (O). Our findings suggest that the fashion exhibited in the top-notch research journals is one of the most influential factors when doctoral students choose a subfield.Economics Research, Doctoral Dissertation, Journal Publication, Ph.D. Economist, Economics Job Market

Speed Discounting and Racial Disparities: Evidence from Speeding Tickets in Boston

Law enforcement officers are allowed to exercise a significant amount of street-level discretion in a variety of ways. In this paper, we focus on a particular prominent kind of discretionary behavior by traffic officers when issuing speeding tickets, speed discounting. Officers partially forgive motorists by writing a lower speed level than the speed that officers observe. Verifying the level of speed discounting by different groups of officers and motorists and ascertaining the presence of racial disparities in this lenient policing are the main objectives of this paper. We find that minority officers, particularly African-Americans, are harsher on all motorists but even harsher on minority motorists regarding speed discounting. The minority-on-minority disparity appears to be stronger in situations involving Hispanic officers, infrequently ticketing officers, male motorists, those driving old vehicles, and minority neighborhoods.police discretion, disparate treatment, racial bias, speeding tickets

Discretionary Behavior and Racial Bias in Issuing Traffic Tickets: Theory and Evidence

Recently, police departments, legislators, media, and the public at large in the U.S. have increasingly been concerned about racial disparities in officers' issuing traffic tickets. Ascertaining the extent to which an observed disparity reflects racial bias is the crucial issue. First, we use a theoretical model which borrows features from the recent literature regarding racial bias in vehicle searches. In our model, motorists, picking the speed to travel at, take into account the probability of getting ticketed and the speed that the officer will cite, while officers maximize a benefit function generically increasing in the speed of ticketed drivers; this benefit function, however, is general enough to allow officers to give certain drivers a break by citing them at a lower speed than they were traveling. Empirically, we exploit the existence of a massive accumulation of speeding tickets at 10 m.p.h. over the speed limit to elicit officers' discretionary behavior and leniency. Surprisingly,about 30% of all ticketed drivers were cited for driving exactly at this particular speed. Using our novel measure of officers' leniency, we find that especially white and male officers are heavily engaged in discretionary behavior. We also find officers' discretion is racially biased; minority officers are less lenient to minority drivers. This is interesting in comparison with Antonovics and Knight (forthcoming) who, using the same data set, found evidence on own-race preferences in vehicle searches.Discretionary behavior, strict behavior, leniency, racial bias, drivers' speeding decision, officers' ticketing and citation decision.

Little strings and T-duality

We study the 2d N = 4 gauge theory descriptions of little strings on type II NS5- branes. The IIB strings on N NS5-branes are described by the N = (4,4) gauge theories, whose Higgs branch CFTs on U(N) instanton moduli spaces are relevant. The IIA strings are described by N = (4,4) circular A_{N-1} quiver theories, whose Coulomb branch CFTs are relevant. We study new N = (0,4) quiver gauge theories for the IIA strings, which make it easier to study some infrared observables. In particular, we show that the elliptic genera of the IIA / IIB strings precisely map to each other by T-duality.Comment: 34 pages, 5 figure

Numerical Modeling of Pile Responses under Lateral Loading Considering the Scour Effects

This thesis focuses on the 3D numerical analysis of the laterally loaded pile. For numerical modeling/analysis, ABAQUS, a widely used commercial software, is used. Non-scour and scour conditions are considered for this thesis. Two elastoplastic constitutive models, Mohr-Coulomb model and Cam Clay model, are applied. Unknown material and interface properties are calibrated based on two references which explained the numerical analysis of the laterally loaded pile under the non-scour condition. Different cases of scour depth, Sd, scour width, Sw, and scour slope angle, a, are applied for the laterally loaded pile analysis under the scour condition. From the results of the numerical analysis under the scour condition, scour depth, Sd, can be the main factor for the pile capacity changes. Scour width, Sw, and scour slope angle, a, are also the other factors which have an influence on the reaction force changes of the laterally loaded pile. This thesis also describes the plastic deformation/strain results of the laterally loaded pile analysis. From the plastic strain results depending on the scour width, the plastic strain appears on the scour slope when the scour width is narrow. On the other hand, when scour width is sufficiently wide, the plastic strain distribution would be similar to the one when the scour width is infinite. This strain distribution state can be shown in both Mohr-Coulomb model and Cam Clay model. In the view of the scour slope angle, the plastic strain in Cam Clay model is more smoothly expanded onto the scour slope than Mohr-Coulomb model

Prize and Risk-Taking Strategy in Tournaments : Evidence from Professional Poker Players

This study examines whether people optimally respond to prize incentives for risk taking in tournaments. I exploit the television game show World Poker Tour as a natural experiment. The results show that professional players strategically choose the degree of risk taking depending on the incentives implied by the prize structure they face. I find that they are more sensitive to losses than to gains

Does Merit-Based Aid Improve College Affordability? Testing the Bennett Hypothesis in the Era of Merit-Based Aid

This study tested the Bennett hypothesis by examining whether four-year colleges changed listed tuition and fees, the amount of institutional grants per student, and room and board charges after their states implemented statewide merit-based aid programs. According to the Bennett hypothesis, increases in government financial aid make it easier for colleges to raise their tuition. Because many statewide merit-based aid programs covered full tuition and fees for students enrolled in their state colleges, I hypothesized that colleges in states that implemented merit-based aid programs would raise student charges or reduce institutional aid for more revenue. Using the difference-in-differences method, I analyzed data from the Integrated Postsecondary Education Data System (IPEDS) from 1987 to 2009. My results showed that colleges significantly changed their prices, but did not always increase the net price that students had to pay. Public colleges in many states with merit-based aid reduced published tuition and fees and increased the amount of institutional grants per student. These results suggest that the implementation of merit-based aid programs could make college education more affordable for those who receive the aid, and may not harm non-recipients

Sibling Size and Investment in Children's Education : An Asian Instrument

This study consistently estimates the trade-off between child quantity and quality by exploiting exogenous variation in fertility due to son preferences. Under son preferences, childbearing and fertility timing are determined conditional on the first child's gender. For the sample of South Korean households I find strong evidence of unobserved heterogeneity across households. However, sibling size has adverse effects on per-child investment in education, in particular when fertility is high