We examine the higher order properties of the wild bootstrap (Wu, 1986) in a linear regression model with stochastic regressors. We find that the ability of the wild bootstrap to provide a higher order refinement is contingent upon whether the errors are mean independent of the regressors or merely uncorrelated with them. In the latter case, the wild bootstrap may fail to match some of the terms in an Edgeworth expansion of the full sample test statistic. Nonetheless, we show that the wild bootstrap still has a lower maximal asymptotic risk as an estimator of the true distribution than a normal approximation, in shrinking neighborhoods of properly specified models. To assess the practical implications of this result we conduct a Monte Carlo study contrasting the performance of the wild bootstrap with a normal approximation and the traditional nonparametric bootstrap.

In the standard analysis of employment dynamics, workers reach unemployment after being Öred. Firing standards rise during recessions, suggesting that the unemployment pool quality rises as well. I show that this is incorrectó a proper analysis of unemployment must also incorporate job leavers. Firings increase relative to quits during recessions, and I present empirical evidence that compositional shifts of this sort result in lower quality workers entering unemployment. I then develop a model of labor market equilibrium in which these compositional shifts arise endogenously, and I study the consequences for employment dynamics. The quality of the unemployment pool declines during recessions, and Örms limit hiring in response. For hiring to return, unemployment pool quality must recover via ináows of higher quality job leavers. In a signiÖcant recession, this recovery may be very slowó aggregate demand may return to pre-recession levels before unemployment pool quality does. This o§ers an explanation for jobless recoveries. The model also reconciles other observed empirical patterns, including countercyclical average labor productivity, a negative relationship between hiring probabilities and unemployment duration, and a convergence of hiring probabilities between the short- and long-term unemployed following increases in Örings and decreases in quits.

This article studies the determinants of the labor force participation of elderly American males and investigates the factors that may account for the changes in retirement between 1950 and 2000. We develop a life-cycle general equilibrium model with endogenous retirement that embeds Social Security legislation and Medicare. Individuals are ex ante heterogeneous with respect to their preferences for leisure and face uncertainty about labor productivity, health status and out-of-pocket medical expenses. The model is calibrated to the U.S. economy in 2000 and is able to reproduce very closely the retirement behavior of the American population. It reproduces the peaks in the distribution of Social Security applications at ages 62 and 65 and the observed facts that low earners and unhealthy individuals retire earlier. It also matches very closely the increase in retirement from 1950 to 2000. Changes in Social Security policy - which became much more generous - and the introduction of Medicare account for most of the expansion of retirement. In contrast, the isolated impact of the increase in longevity was a delaying of retirement.

This paper investigates how social interactions among friends shape fertility. We specifically examine whether and how friends’ fertility behaviour affects an individual’s transition to parenthood. By integrating insights from economic and sociological theories, we elaborate on the mechanisms via which interactions among friends might affect an individual’s risk of becoming a parent. By exploiting the survey design of the Add Health data, we follow a strategy that allows us to properly identify interaction effects and distinguish them from selection and contextual effects. We engage in a series of discrete time event history models with random effect at the dyadic level. Results show that, net of confounding effects, a friend’s childbearing increases an individual’s risk of becoming a parent. We find a short-term, curvilinear effect: an individual’s risk of childbearing starts increasing after a friend’s childbearing, it reaches its peak around two years later, and then decreases.

Many environmental policies have clear public health impacts and are designed to improve health outcomes either by reducing the environmental health risks individuals encounter in their daily lives, or by encouraging more healthy lifestyles. One way of testing the effectiveness of these policies is to examine the behavioral changes they induce. In this dissertation, I use the American Time Use Survey (ATUS) to estimate behavioral responses to several environmental policies by examining how individuals shift the amount of time they spend in various activities during the day. The ATUS is a nationally representative, federally administered survey on time use in the United States. The survey collects information on all activities performed by respondents during a designated 24-hour period. It was first administered in 2003 and has continued throughout every year since, allowing me to collect responses for an 8-year period, 2003-2010. Because each respondent provides detailed information on his/her activities during the designated 24-hour period, I am able to determine how much time each person spends in various morning, afternoon and, evening activities that may be affected by the policies of interest. Although the ATUS has been in existence for 9 years, it has been under utilized in the economic literature. Researchers have traditionally focused primarily on the budget constraint faced by individuals and households, ignoring the time constraint. Examining how time use is affected by exogenous policy changes has the potential to shed light on many economic questions. For example, the literature has found that as gas prices increase consumption decreases, however; at a very inelastic rate. Analysis of time-use data could add to these findings by examining what behaviors are most affected. Do the higher prices cause individuals to carpool or take public transit to work, or do they contribute to fewer recreational excursions? Do the higher prices make commutes longer or shorter? Does this affect the amount of time spent working during the day? Time use data sets . . .

Classical and contemporary literature on immigration has been driven by questions concerning how and when immigrants assimilate to American society. Understanding the assimilation process is especially important with regard to adolescents, whose trajectory will drive the future incorporation of immigrant groups into U.S. society.

Among immigrant Hispanic adults in diverse communities, educational attainment is an important predictor of their future social and economic opportunity. Drawing on segmentedassimilation theory, this study examined the contribution of community characteristics-new/established destination type, presence of co-ethnic networks and co-ethnic human capitaltocollege enrollment outcomes among Hispanic youth in the Educational Longitudinal Study: 2002. Although youth whose families resided in new immigrant destinations were initially found to have more human capital, once selection into communities was accounted for via propensity score matching, those youth were less likely to enroll in four-year colleges, adjusting for academic performance, course-taking, and immigration-related factors (e.g., English nativity). However, their decreased likelihood of four-year college enrollment was directly explained by differences in co-ethnic resources in new destinations.

Three Worlds of Relief examines the role of race and immigration in the development of the American social welfare system by comparing how blacks, Mexicans, and European immigrants were treated by welfare policies during the Progressive Era and the New Deal. Taking readers from the turn of the twentieth century to the dark days of the Depression, Cybelle Fox finds that, despite rampant nativism, European immigrants received generous access to social welfare programs. The communities in which they lived invested heavily in relief. Social workers protected them from snooping immigration agents, and ensured that noncitizenship and illegal status did not prevent them from receiving the assistance they needed. But that same helping hand was not extended to Mexicans and blacks. Fox reveals, for example, how blacks were relegated to racist and degrading public assistance programs, while Mexicans who asked for assistance were deported with the help of the very social workers they turned to for aid.Drawing on a wealth of archival evidence, Fox paints a riveting portrait of how race, labor, and politics combined to create three starkly different worlds of relief. She debunks the myth that white America's immigrant ancestors pulled themselves up by their bootstraps, unlike immigrants and minorities today. Three Worlds of Relief challenges us to reconsider not only the historical record but also the implications of our past on contemporary debates about race, immigration, and the American welfare state.

Little is known regarding the epidemiology of chronic rhinosinusitis (CRS) in racial and ethnic minorities in the United States. This study was designed to comprehensively evaluate the current prevalence of CRS across various treatment settings to identify possible disparities in health care access and use between racial and ethnic populations.

Cities are endowed with and accumulate assets based on their unique histories, which in turn define the choice set of the present. These assets range from the natu- ral—sheltered ports, fertile land—to the constructed—concrete and cement, institu- tions and people. This dissertation examines the effects of one of these assets, urban rail, on residential location and travel behavior, from the era of horsecars and street- cars to the present in Boston. It explores the hysteretical effects of past access to rail—the extent to which the urban system retains the impacts of rail even when it no longer exists. Current density and travel behavior are measurably influenced by past access to rail. The built environment and demographic patterns are found to be the strongest mechanism for these persistent effects. Past access to rail has shaped the city, and that shape has, in turn, affected travel behavior. For density and auto ownership there is an additional measurable effect of past access unexplained by the built en- vironment or demographic patterns. This legacy is plausibly explained by cultural effects—mnemonics—due to personal history, behavioral norms, and zoning/politics. Past access to rail has a stronger effect on density than on auto ownership. The daily choice of modes is almost entirely conditioned on current circumstances. Because places shaped by rail retain its imprint, these findings imply that there is need to consider how policy decisions will influence the city’s future choice set. The greatest benefits from the endowments of urban rail are likely where redevelopment costs are low and growth potential is high—particularly light industrial areas near strong central cities. Realizing these changes requires mechanisms that allow and en- courage government and private entities to be patient with the long time frames for adaptation to rail infrastructure. One such step is requiring, rather than allowing, supportive zoning and other policies within the Federal Transit Administration’s New Starts capital program—including such items as increased as-of-right density, reason- able limits on parking, car sharing, and graduated drivers licensing laws. This research strengthens prior findings that similar approaches can encourage sustainable cultural norms.

Site selection bias occurs when the probability that partners adopt or evaluate a program is correlated with treatment effects. I test for site selection bias in the context of the Opower energy conservation programs, using 111 randomized control trials (RCTs) involving 8.6 million households across the United States. Predictions based on rich microdata from the first ten replications substantially overstate efficacy in the next 101 sites. There is evidence of two positive selection mechanisms. First, local populations with stronger preferences for environmental conservation both encourage utilities to adoptthe program and are more responsive to the treatment. Second, program managers initially target treatment at the most responsive consumer sub-populations, meaning that efficacy drops when utilities expand the program. While it may be optimal to initially target an intervention toward the most responsive populations, these results show how analysts can be systematically biased when extrapolating experimental results, even after many replications. I augment the Opower results by showing that microfinance institutions(MFIs) that run RCTs differ from the global population of MFIs and that hospitals that host clinical trials differ from the national population of hospitals.

Contemporary race and immigration scholars often rely on historical analogies to help them analyze Americas current and future color lines. If European immigrants became white, they claim, perhaps todays immigrants can as well. But too often these scholars ignore ongoing debates in the historical literature about Americas past racial boundaries. Meanwhile, the historical literature is itself needlessly muddled. In order to address these problems, the authors borrow concepts from the social science literature on boundaries to systematically compare the experiences of blacks, Mexicans, and southern and eastern Europeans (SEEs) in the first half of the 20th century. Their findings challenge whiteness historiography; caution against making broad claims about the reinvention, blurring, or shifting of Americas color lines; and suggest that the Mexican story might have more to teach us about these current and future lines than the SEE one.

Recent research postulating that the diffusion of confidential access to the birth control pill to young women in the United States contributed to the dramatic social changes of the late 1960s and 1970s has not adequately accounted for the largely contemporaneous diffusion of access to abortion. Estimates using a new panel of data on state policies related to access to the pill and abortion indicate that while access to the pill may have played a role in the sexual revolution, it had little effect on the probabilities of entering into marriage and parenthood at a young age. In contrast, both the legalization of abortion and the enactment of laws permitting young unmarried women to consent to it led to substantial delays in marriage and motherhood.

Privacy Preserving Data Mining (PPDM) addresses the problem of developing accurate models about aggregated data without access to precise information in individual data record. A widely studied perturbation-based PPDM approach introduces random perturbation to individual values to preserve privacy before data are published. Previous solutions of this approach are limited in their tacit assumption of single-level trust on data miners. In this work, we relax this assumption and expand the scope of perturbation-based PPDM to Multilevel Trust (MLT-PPDM). In our setting, the more trusted a data miner is, the less perturbed copy of the data it can access. Under this setting, a malicious data miner may have access to differently perturbed copies of the same data through various means, and may combine these diverse copies to jointly infer additional information about the original data that the data owner does not intend to release. Preventing such diversity attacks is the key challenge of providing MLT-PPDM services. We address this challenge by properly correlating perturbation across copies at different trust levels. We prove that our solution is robust against diversity attacks with respect to our privacy goal. That is, for data miners who have access to an arbitrary collection of the perturbed copies, our solution prevent them from jointly reconstructing the original data more accurately than the best effort using any individual copy in the collection. Our solution allows a data owner to generate perturbed copies of its data for arbitrary trust levels on- demand. This feature offers data owners maximum flexibility.

Since the 1980s, social science research has emerged on gender and immigration to the United States as a result, in part, of the pronounced increase in immigration to the US. It has documented the way in which immigration is changing the social fabric of US society as well as how gender roles are being positioned within society. Scholarship on Latino immigration and gender has also evolved throughout the past decades, providing much needed insight about migration outcomes for Latina immigrants and their effects on these women’s situated roles. Consequently, scholars have focused their work mainly on Latinas in their host communities, as workers, family members and community organizers. Transnationalist theories have contributed to understanding how Latinas organize their lives across borders; however, work is still needed to understand how the perspective of the immigrant life cycle (defined as life in the country of origin, the process of migration and life in the host country) informs migration outcomes for immigrant Latina women. In order to contribute to this understanding, this study, using an ethnographic approach, looks at the life stories of five low-income Latina immigrant domestic workers activists in Montgomery County, MD, to document their experience and to understand the factors that influence their civic mobilization for their collective rights. The central research question is: What are the factors conducive to female immigrants’ collective mobilization for human rights? More specifically, what are the factors in the women’s life course that account for mobilization and what are the structural factors in the host country that support this effort? This ethnographic study contributes to the literature on domestic work and migration by examining the subjective aspects of the Latinas’ experience as they evolve as activists and mobilize for their rights as workers, particularly from the perspective of identity formation across the immigrant life cycle. The study also shows that domestic work conditions are determined by the specific relationship between poverty, human mobility and gender at a local and national level.

Marriage has declined since 1960, with the drop being bigger for non-college educated individuals versus college educated ones. Divorce has increased, more so for the non-college educated vis--vis the college educated. Additionally, assortative mating has risen; i.e., people are more likely to marry someone of the same educational level today than in the past. A unified model of marriage, divorce, educational attainment and married female labor-force participation is developed and estimated to fit the postwar U.S. data. The role of technological progress in the household sector and shifts in the wage structure for explaining these facts is gauged.

This paper posits a notion of the value of an individual's human capital and the associated return on human capital. These concepts are examined using U.S. data on male earnings and financial asset returns. We find that (1) the value of human capital is far below the value implied by discounting earnings at the risk-free rate, (2) mean human capital returns exceed stock returns early in life and decline with age, (3) the stock component of the value of human capital is smaller than the bond component at all ages and (4) human capital returns and stock returns have a small positive correlation over the working lifetime.

This dissertation can broadly be categorized into two parts. The first part analyzes the causes of racial residential segregation, and the second focuses on its consequences. In the first part of my dissertation, I attempt to analyze whether population suburbanization causes racial residential segregation. The key contribution of this paper to the existing literature is the implementation of instrumental variable regression in order to identify the direction of causality between the two. Population suburbanization is instrumented with the number of highways running through central cities of metropolitan areas in the 1947 highway plan. Estimation results suggest that population suburbanization has caused U.S. metropolitan areas to be more residentially segregated. Had there been no suburbanization between 1960 and 2000, racial residential segregation on average would have declined by about 4 percentage points more than what is observed in the data. The second part of my dissertation analyzes the impact of racial residential segregation on black employment outcome in U.S. metropolitan areas. In particular, this paper re-examines the spatial mismatch hypothesis. The main contribution of this research to the previous literature is to test the spatial mismatch hypothesis in an intertemporal framework. Using decadal census data from 1970 to 2000 in a panel setting, the study allows us to test the persistence of the spatial mismatch problem. Causal estimates from the instrumental variables regression suggest that although racial residential segregation adversely affected black employment outcome in the 1970s and 1980s, the effect is not significant for 1990 and 2000. Furthermore, racial residential integration does not significantly improve the employment outcomes for prime-aged low-skilled blacks. On the other hand, decentralization of manufacturing, wholesale and retail trade (MWR) jobs significantly affects the unemployment rate for low-skilled blacks. For the panel regression, a one standard deviation fall in central city employment in these industries raises low-skilled black unemployment rate by 1.9 percentage points. However, it is not likely that this effect is disproportionately greater for MSAs with higher levels of residential segregation. Results obtained in this paper indicate that improvement in job accessibility does not significantly improve the employment outcomes for low-skilled blacks. If labor demand shifts away from the industries hiring low-skilled laborers, which in fact happened over the past few decades, then it would lower their employment rates even if those jobs are accessible. In that case, any low-skilled laborer irrespective of race would face unemployment problems arising from such shifts. But if there is racial discrimination in employment, then it would hurt the blacks more than other nonminority group even in the absence of skill or spatial mismatch.

In the Upper South, free blacks stood out as a living breathing contradiction to the institution of race-based slavery. State legislatures continuously debated and discussed the issue, and created a plethora of laws to restrict the freedoms given to African Americans. However, through a comparison of two piedmont locales, Bedford County, Virginia, and Washington County, Virginia, this thesis reveals the flexibility of execution of state laws on the ground. The work argues that state laws did not necessarily dictate black experiences in freedom. Instead, free black experience can be shown through the ways that whites enforced the laws, a process that often relied on local factors within each community. Through free black experiences in manumission and registration, in the local economy, and in the county courthouse, this work argues that significant differences existed between free black experiences within different localities in the Upper South, and that the strength of the institution of slavery directly affected race relations on the ground. In Washington County, slavery found much opposition in the proximity of the free state of Pennsylvania and the migratory work force associated with the changing economy that resulted in the decline of slavery and an increase in the free black population. In Bedford County, slavery remained relatively strong through the production of tobacco while the small free black population remained stable. Free blacks in Bedford County faced a more informal enforcement of state legislation in favor of a more localized legal culture based on reputation within the white community. In Washington County, whites utilized the law in order to control portions of the population that questioned the wavering institution of slavery. Free blacks in Bedford County faced a more informal enforcement of state legislation in favor of a more localized legal culture based on reputation within the white community. In Washington County, whites utilized the law in order to control portions of the population that questioned the wavering institution of slavery. Although the enforcement of state laws differed within each community, free blacks in both communities frequently interacted with whites in the community. Their interactions within the community laid the foundation for local reputation and the ways authorities would enforce the law.

This paper estimates poverty trends in Wisconsin between 2008 and 2010, for the overall population and for children and the elderly, using an alternative poverty measure similar to the federally implemented Supplemental Poverty Measure, but customized to better reflect the placespecific needs and resources of Wisconsin. Unlike the official poverty measure, our alternative measurement (the Wisconsin Poverty Measure or WPM) considers tax credits and noncash benefits, and adjusts for work-related and medical-care expenses as well as for relative living costs, statewide and across sub-state regions. Using data from the American Community Survey and Wisconsin administrative records, the WPM shows essentially no change in state poverty rates between 2008 and 2009 and a decline between 2009 and 2010, from 11.1 percent to 10.3 percent, although state poverty levels calculated via the official measure continued to increase between 2008 and 2010. We discuss the policy implications of these results.