This paper demonstrates that immigration flows respond to differences in labor market conditions by documenting the change in newly arriving low-skilled immigrants location decisions in response to the increase in native employment induced by welfare reform. Previous studies comparing cities receiving large immigrant flows to cities with smaller influxes have found very little effect on natives wages and employment. These results are consistent with a model in which a mobile production factor equilibrates labor market returns across geography. This paper provides direct evidence that immigration flows serve this function, and it is the first to do so using an identifiable source of exogenous variation. The empirical methods I use improve upon previous immigrant location studies by explicitly allowing for unobserved city attributes that potentially differ across sending countries. Using welfare participation rates as an instrument for changes in native labor supply, I find that immigrant flows shifted away from cities with more welfare leavers toward cities with smaller increases in native competition. The results are most consistent with endogenous location selection based on relative labor market prospects, which I present in a random utility discrete choice framework. The extent of this selection is substantial: for each extra native woman working in a city as a result of welfare reform, 0.83 fewer female immigrants choose to live and work there.

This paper focuses on differences in the timing of arrival among immigrants in the same household because earlier arriving immigrants may be able to accelerate the adaptation of later arrivals through the sharing of knowledge or scouting out of opportunities. Although U.S. immigration policy encourages family members, especially spouses, to immigrate together, it also allows closely related immigrants to enter the country at separate times. Using U.S. 2000 census data, we describe patterns of timing of arrivals among immigrants in the same household. Results show that over a third of husbands and wives arrive in different years and that the sequence is gendered, with men more often arriving before the women. These patterns differ by country of origin, and years of separation differ by family composition.

Where does adaptation to innovation take place? The supply of educated workers and local industry structure matter for the subsequent location of new work - that is, new types of labor-market activities that closely follow innovation. Using census 2000 microdata, the author shows that regions with more college graduates and a more diverse industrial base in 1990 are more likely to attract these new activities. Across metropolitan areas, initial college share and industrial diversity account for 50% and 20%, respectively, of the variation in selection into new work unexplained by worker characteristics. He uses a novel measure of innovation output based on new activities identified in decennial revisions to the U.S. occupation classification system. New work follows innovation, but unlike patents, it also represents subsequent adaptations by production and labor to new technologies. Further, workers in new activities are more skilled, consistent with skill-biased technical change.

We present a simple test of the monocentric model based on variations in interurbanwage differentials by occupation. We classify occupations as more or less centralaccording to the density of employment where job holders in those occupations work.Our conjecture is that more central occupations receive differentially higher wages inlarger cities, since workers in those occupations face a less desirable locus of housingprices and commuting times than those who have jobs in residential areas. The resultspresented in the empirical section are consistent with this hypothesis, and they are robustto the inclusion of individual-specific human capital variables and city-specific controls.These findings have implications for inter-urban cost of living indexes, where wages areused to approximate the true cost of living.

Existing literatures emphasize the estimates of price and income elasticities for housing demand over the whole population. This dissertation analyzes and quantifies different responses of whole population and subgroups for housing demand categorized by family structure and residential area. Micro data for the U.S. are used to analyze the effects of family structure and residential area on tenure choice and housing demand. This data is used to model hedonic house price, tenure choice and housing demand. This dissertation presents the significant differences in the housing demand between the subgroups.First, the effect of family structure on tenure choice and housing consumption is very significant. Single person and single parent households are less likely to own their house, while couples with children are likely to consume more housing. Second, the location of households affects tenure choice significantly. The households living in the center of a big city are less likely to own than the households living small urban and rural areas. Third, each family structure has different income and price elasticities of housing demand. Single parent households are more responsive to change in income and less responsive to change in price compared to other types of households. Single person household has relatively high price elasticity.

There are competing predictions regarding the relationship between military service, functional limitations, and disability. Some research suggests military service should lead to lower rates of functional limitations and disability, particularly for those from disadvantaged backgrounds. Other research indicates military service, particularly service during war time, should increase the risk of functional limitations and disability. However, despite the numerous studies on health conditions among veterans, there are very few studies that use national data to examine the differences in functional limitations and disability between veterans and nonveterans. Furthermore, there are no studies that consider how these relationships vary by race/ethnicity and gender. The purpose of this research is to examine these issues with census data from the 2000 Public Use Microdata Sample. The findings indicate that veterans are significantly more likely to have a functional limitation or disability than nonveterans. However, this relationship varies substantially across race/ethnicity and gender. Black, Native American, and Multiracial veterans have significantly higher odds of having functional limitations and disabilities than their nonveteran counterparts and Non-Hispanic White nonveterans. Furthermore, female veterans overall, and in these three racial/ethnic groups in particular, have substantially higher odds of having functional limitations or disability than female nonveterans and males regardless of veteran status. Possible explanations for these observed differences are discussed.

The three chapters of this dissertation examine evidence on relationships between patterns of agglomeration within the United States and workers’ industry and occupation decisions. The first chapter investigates agglomeration economies in the form of job search and matching. Using data from the U.S. Census and the Current Population Survey, I show that, on average, workers change occupation and industry less in more densely populated areas. These results provide evidence in favor of increasing-returns-to- scale matching in labor markets. The second chapter examines the distribution of new work across U.S. cities. Using Census microdata, I find that new work—that is, new types of activities that closely follow innovation—concentrates in cities that initially have more college graduates and a more diverse industrial base. This evidence is consistent with concentrations of human capital facilitating regional adaptation to new technologies. Finally, in the third chapter, I explore why industrial diversity is important for regional adaptation to innovation. Using employment estimates for detailed new occupations from the Occupation Employment Statistics, I find that diversified cities use new activities more intensively, even as these activities mature. These results suggest that a “nursery cities” model of industrial structure and regional innovation may not fully describe the agglomeration pattern of new activities.

Industrial revolution is fundamentally linked with the rise of factories and the decline of skilled artisans in manufacturing. Most scholars agree that factories as compared to artisan shops were intensive in unskilled labor. Indeed, the hallmark of the early factories is the utilization of division of labor of relatively unskilled workers. This paper explores whether the massive influx of unskilled immigrants between 1840 and 1920, by significantly increasing the ratio of unskilled to skilled labor endowment, contributed to the growth and spread of factory manufacturing in the United States. The data indicate that immigration not only contributed to the growth and spread of factories but it also contributed to the growth of cities.

In this Chapter, we describe representative algorithms of the two key supervised inductive machine learning techniques, namely, decision trees and rule algorithms. We present both basic and more advanced versions of decision trees, such as the ID3, C4.5, ID5R, and 1RD algorithms. Note that all decision tree algorithms are based on the fundamental concept learning algorithm originally proposed by Hunt. On the other hand, most rule algorithms have their origins in the set-covering problem first tackled by Michalski. The rule algorithms are represented by the DataSqueezer algorithm and the hybrid algorithms by the CLIP4 algorithm that combines the best characteristics of decision trees and rule algorithms.

To describe the determinants of delayed HIV presentation in one Northern California County, the authors identify persons with an opportunistic infection (OI) at HIV diagnosis. From 20002002, a sample of HIV patients attending a public AIDS program (n=391) were identified. Immigrants composed 24% of our sample; 78.7% of immigrants were Hispanic. Immigrants, compared to U.S.- born patients, presented with lower initial CD4+ counts at diagnosis than U.S.-born patients (287 cells/mm3 vs. 333 cells/mm3, p=0.143), were more likely to have an OI at HIV diagnosis (29.8% vs. 17.2%, p=0.009), and were more likely to be hospitalized at HIV diagnosis (20.2% vs. 12.5%, p=0.064). We found only immigrant status was significantly and independently associated with delayed presentation. Interviews with 20 newly HIV diagnosed Hispanic patients suggest lack of knowledge regarding HIV risk, social stigma, secrecy and symptom driven health seeking behavior all con-tribute to delayed clinical presentation. The main precipitants of HIV testing for immigrants were HIV/AIDS related symptoms and sexually transmitted infection (STI)/HIV diagnosis in a sexual partner. These results support augmentation of STI/HIV voluntary clinical testing and partner notification services along the Mexico-California migrant corridor.

One consequence of demographic change is substantial shifts in the age distribution of the working age population. As the baby boom generation ages, the usual historical pattern of there being a high ratio of younger workers relative to older workers is increasingly being replaced by a pattern of there being roughly equal percentages of workers of different ages. One might expect that the increasing relative supply of older workers would lower the wage premium paid for older, more experienced workers. This paper provides strong empirical support for this hypothesis. Econometric estimates imply that the size of one's birth cohort affects wages throughout one's working life, with members of relatively large cohorts (at all stages of their careers) earning a significantly lower wage than members of smaller cohorts. The cohort size effect is of approximately the same magnitude for men and for women. Our results suggest that cohort size effects are quantitatively important and should be incorporated into public policy analyses.

Residential segregation has played a central role in theories of minority entrepreneurship. This study integrates two theories in the extant literature on minorities and urban areas (spatial assimilation theory and labor market disadvantage theory); and tests a hypothesis on the self-employment likelihood of black Americans. Descriptive statistics indicate a negative relationship between black-white segregation and increasing socioeconomic status (SES), although blacks remain considerably residentially segregated from whites of similar SES. The model results indicate that, after controlling for a number of factors, segregation of high SES blacks and whites in a metropolitan area is associated with higher likelihood of black self-employment.

In 1957 the state of Mississippi amended its marriage law. Changes included raising the minimum age for men and women, parental consent, compulsory blood tests and proof of age. As a result, the number of marriages performed in Mississippi fell by more than 60 percent in 2 years. This paper examines the impact of the change in marriage law on marriage rates, fertility and educational attainment of women. We find that black marriage rates were affected more than white marriage rates. Among blacks women there was a decline in fertility and greater educational attainment in the group that was affected by the law. For whites, the results are mixed. There is weak evidence towards a decline in fertility and increase in educational attainment. However, among whites we find an upward trend in illegitimate births starting in the same time period.

This paper examines the evolution of the Mexican-born workforce in the United States using data drawn from the decennial U.S. Census throughout the entire 20th century. It is well known that there has been a rapid rise in Mexican immigration to the United States in recent years. Interestingly, the share of Mexican immigrants in the U.S. workforce declined steadily beginning in the 1920s before beginning to rise in the 1960s. It was not until 1980 that the relative number of Mexican immigrants in the U.S. workforce was at the 1920 level. The paper examines the trends in the relative skills and economic performance of Mexican immigrants, and contrasts this evolution with that experienced by other immigrants arriving in the United States during the period. The paper also examines the costs and benefits of this influx by examining how the Mexican influx has altered economic opportunities in the most affected labor markets and by discussing how the relative prices of goods and services produced by Mexican immigrants may have changed over time.

This paper argues that the increase in young male incarceration rates played a significant role in the decline in teen birthrates during the 1990s. Using 1980, 1990, and 2000 Census microdata, I show that a one standard deviation increase in white (black) young male incarceration rates was associated with a 1.12 (2.15) percentage point decline in the fertility of white (black) female teens in the lowest income quintile. Incarcerating one additional white (black) male is associated with 0.28 (0.45) fewer births. Teen fertility is negatively related only to the incarceration rates of males empirically likely to father the babies of teen mothers, such as 20 year-old males or males of the same race. Instrumenting for incarceration with court orders on jail overcrowding magnifies the estimates considerably, suggesting that the OLS estimates may understate the true causal impact of incarceration on teen fertility. My results suggest that models of sex ratios and bargaining power for teenagers need to allow for heterogeneity in the types of male sexual partners.

Purpose: Middle Eastern (ME) population is rapidly growing in the US but cannot be easily identified in cancer registry or other databases for epidemiological research. The purpose of this study was to develop a list of common Middle Eastern surnames and validate it by linking with a cancer registry incidence files. Methods: Surnames and place of birth in the Middle East were obtained from various sources. After exclusion of the non-specific entries, the final combined list included 49,610 surnames and was matched with the California Cancer Registry incidence file for 19882003. Results: Overall, 1.4% of all registered cases were positively identified as ME that is similar to the proportion ofME population in California. Two third of the identified cases had known place of birth in the Middle East and of those, 70% were non-Arabs. The sensitivity of the list in detecting ME birth in men and women are 91% and 86%, respectively. The positive predictive values for men and women are 72% and 65%. The specificity and negative predictive values are universally over 99%. Conclusion: The high accuracy reported forthis Middle Eastern surname list (MESL) makes it a valuable tool for epidemiological studies of this ethnic population.

The social, behavioral and economic sciences (SBEs) do not currently benefit from a unified workflow environment for the quantitative analysis of social survey data. Some unified models integrating data storage, data management and data analysis do exist, for example the NESSTAR, IPUMS and LIS projects. However all of these services are focused on a limited number of data resources and functionalities. The Cyberinfrastructure could be exploited to develop and support a more generic workflow environment. In this paper, we build upon earlier work in providing a specialist data access service to social scientists (the GEODE project), to outline a proposed framework for a generic quantitative social science infrastructural service based on open standards.