This paper summarizes what is known about the labor supply of older men, defined as those 55 and over. The topic is of great interest because older individuals will comprise a much greater portion of the population, so their labor supply will have a significant impact on national output, tax revenues, and the cost of means-tested programs. Most importantly, a greater proportion of older individuals will need to work than do at present, because retirement income systems are contracting and working longer is the only way for most to ensure financial security in their old age. The focus is on men, because women's work patterns reflect the increasing participation of cohorts over time as well as the factors that affect retirement behavior.Section I of this paper describes the changes to the retirement income system that will require people to work longer. Section II summarize the long-term decline in labor force activity among older individuals and the factors that contributed to that trend. Section III describes the recent turnaround in the labor force activity of older people and the changes in Social Security and pensions that likely led to the reversal. In an attempt to determine whether the labor supply of older workers will continue to increase, Section IV describes changes in work patterns that have emerged and the implications of such changes on labor supply. Section V addresses the issue of health to ascertain the extent to which older people can be expected to continue in the labor force, noting that for 15 to 20 percent of the workforce continued employment will be impossible. Section VI discusses the remaining incentives to retire--namely, the availability of Social Security at 62 and the lack of flexible employment arrangements. Section VII concludes.

Yu has developed a straightforward method for calculating the Immigration Multiplier measuring the chain migration process. He clarifies the definition of Immigration Multiplier and breaks the concept down into Immigration Unification Multiplier (for measuring the family unification component of chain migration) and the Immigration Reproduction Multiplier (for measuring the immigrant fertility and reproduction component of chain migration). Using the 2000 Census data and national immigration data sets, Yu calculates the Immigration Multipliers for chain migration in the U.S. for all regions and some top immigrant-sending countries. The results illustrate the impact of chain migration and the different immigration patterns among racial/ethnic immigrant groups. Chain immigration exists in the U.S., and the immigration multiplier patterns vary by regions and countries from which the immigrants come.

Gender is fundamental to understanding ethnic marriage patterns, particularly in the case of the United States of America, where immigrant streams have long been sexselective. While for much of a century (1880-1970) male immigrants typically outnumbered females 110:100, for Greeks and Italians the adult sex ratio averaged 150, and Norwegians, Mexicans, Austrians, and others were not far behind at 125. In caste societies, polyandry, celibacy or same-sex unions might be the means for attaining equilibrium in socially-constructed marriage markets. In the United States, outmarriage is the escape valve, as far back in the past.

Several studies have identified a substantial border penalty on the earnings of individuals who reside in areas close to the U.S. - Mexico southern border. This paper uses IPUMS data based on the 2000 decennial census and the 2005 American Community Survey (ACS) 2005 samples to analyze whether this border penalty changed during the early 2000s. We first document that a border/interior earnings gap exists for the three groups of workers, despite higher average education levels within the same ethnic group along the border. Morerover, while the border earnings penalty is particularly pronounced among Mexican immigrants (-0.128), Mexican immigrants and non-Hispanic whites along the border experienced an earnings improvement between 2000 and 2005 compared to their counterparts in the rest of the U.S. (of approximately 4.4% for Mexican immigrants and 2.7% for non-Hispanic whites). Studying the manufacturing, construction and trade sectors in more detail, we find that the U.S. born Mexican-Americans are associated with a substantially higher border penalty if working in any of these sectors. The more stable border penalty premiums for Mexican immigrants (with the exception of construction (-0.213)), suggest a high degree of adaptation to the changing business cycles in the early 2000s. As a whole, our findings are consistent with at least two explanations: i) the more mobile Mexican immigrant population might be responding faster to changes in the U.S. business cycles; and ii) Mexican immigrants appear to be gaining ground versus Mexican-Americans in the job pool.

Pattern discovery techniques, such as association rule discovery, explore large search spaces of potential patterns to find those that satisfy some user-specified constraints. Due to the large number of patterns considered, they suffer from an extreme risk of type-1 error, that is, of finding patterns that appear due to chance alone to satisfy the constraints on the sample data. This paper proposes techniques to overcome this problem by applying well-established statistical practices. These allow the user to enforce a strict upper limit on the risk of experimentwise error. Empirical studies demonstrate that standard pattern discovery techniques can discover numerous spurious patterns when applied to random data and when applied to real-world data result in large numbers of patterns that are rejected when subjected to sound statistical evaluation. They also reveal that a number of pragmatic choices about how such tests are performed can greatly affect their power.

Given a set of multidimensional data points, skyline query retrieves a set of data points that are not dominated by any other points. This query is useful for multi-preference analysis and decision making. By analyzing the skyline query, we observe a close connection between Z-order curve and skyline processing strategies and propose to use a new index structure called ZBtree, to index and store data points based on Z-order curve. We develop a suite of novel and efficient skyline algorithms, which scale very well to data dimensionality and cardinality, including (1) ZSearch, which processes skyline queries and supports progressive result delivery; (2) ZUpdate, which facilitates incremental skyline result maintenance; and (3) k-ZSearch, which answers k-dominant skyline query (a skyline variant that retrieves a representative subset of skyline results). Extensive experiments have been conducted to evaluate our proposed algorithms and compare them against the best available algorithms designed for skyline search, skyline result update, and k-dominant skyline search, respectively. The result shows that our algorithms, developed coherently based on the same ideas and concepts, soundly outperforms the state-of-the-art skyline algorithms in their specialized domains.

政府が所管する各種統計の個票データを公開する方法が議論されて久しい。議論の具体 的な内容や背景については、近年予定されている統計法の改正などに関連した報告書がす でに様々に公開されているので、それらに譲る。本調査では、北米における政府統計の個 票データ公開の現状を概観･報告することで、わが国における政府統計の個票データを利用 する具体的な仕組みづくりの一助としたい。 具体的には、アメリカ合衆国労働統計局（Bureau of Labor Statistics、以下 BLS と略す）お よびセンサス局（United States Bureau of the Census、通称 Census Bureau、以下 BOC と略す）、 カナダ統計局（Statistics Canada、以下 StatsCAN と略す）において設置･運営されている Onsite Research の方法をまとめる。

Married women's labor force participation has increased dramatically over the last century. Why this has occurred has been the subject of much debate. This paper investigates the role of culture as learningin this change. To do so, it develops a dynamic model of culture in which individuals hold heterogeneous beliefs regarding the relative long-run payoffs for women who work in the market versus the home. These beliefs evolve rationally via an intergenerational learning process. Women are assumed to learn about the long-term payoffs of working by observing (noisy) private and public signals. They thenmake a work decision. This process generically generates an S-shaped figure for female labor force participation, which is what is found in the data. The S shape results from the dynamics of learning. I calibrate the model to several key statistics and show that it does a good job in replicating the quantitative evolution of female LFP in the US over the last 120 years. The model highlights a new dynamic role for changes in wages via their effect on intergenerational learning. The calibration shows that this role was quantitatively important in several decades.

Even in well-mapped countries, minor civil division (MCD) boundaries change repeatedly, often while keeping the same place names. The shifting sands problem complicates issues of data compatibility in longitudinal studies, when it doesnt preclude a line of inquiry altogether. In other instances, though historical sources often record local place names, the precise locations are unknown. These two issuesboundary variability and imprecisionlimit the usefulness of historical GIS in matters of current policy interest, and in studies employing both natural science and social science data sets. This paper suggests a solution to both problems using the U.S. Geological Services GNIS database, and presents a brief case study in the use of this approach.

In this paper we study whether location-specific price variation likely affects statistical inference and theoretical interpretation in the empirical implementation of human capital earnings functions. We demonstrate, in a model of local labor markets, that the "return to schooling" is a constant across locations if and only if preferences are homothetic/a special case that seems unlikely. Our theory predicts that the returns to education will be relatively lower in expensive high-amenity locations. Examination of U.S. Census data for 1980, 1990, and 2000, suggests that the return to a college education, relative to a high school education, varies widely across metropolitan areas (e.g., in 1990 the return in Houston is 0.54 while in Seattle it is only 0.33), and the return to education is generally lower in expensive locations. Our findings call into question standard empirical exercises in labor economics which treat the returns to education as a single parameter.

There have been several pronounced trends in cities across the U.S. over the last two decades. First, skill levels are diverging. Cities like Boston, with a higher initial share of college graduates, have had a greater subsequent increase in measurable skill levels. Second, these cities have also undergone faster growth in land prices, compared to other cities. In addition, the patterns of inter-city migration have changed. Cities like Boston used to attract both skilled and unskilled workers, but unskilled workers have been moving out of these cities, while skilled workers have continued to move in. The argument in this thesis is that the advent of new technologies may, in part, explain the observed changes, through an increase in the possibility of domestic outsourcing and computerization. On the empirical front, this thesis provides evidence of domestic outsourcing and computerization. It presents stylized facts on city housing prices, skill levels, and skill premiums. In addition, changes in migration patterns by skill are examined. On the theoretic front, this thesis presents models that rationalize the observed facts. The key idea is that skilled workers need unskilled support services. Before the advent of the new technologies, skilled workers in cities like Boston must hire expensive local unskilled workers. With the new technologies, skilled workers can use computers instead or hire inexpensive unskilled workers in cities like Omaha, Nebraska. This thesis shows that the obsolescence or shuffling of unskilled jobs can affect the location of people as well as city characteristics.

With the introduction and dispersion of the birth control pill and the national legalization of abortion, the US witnessed a major fertility revolution in the 1960s andearly 1970s. Greater fertility control decreased the relative benefit of more committed relationships to less committed relationships. Since cohabitation falls in the intermediate range of commitment, the existing theory, including a new model presented in this paper, makes an ambiguous prediction of the impact of greater fertility control on cohabitation. The causal effect is empirically estimated using plausibly exogenous variation in state laws granting access the pill and abortion. The results suggest that legal access to the pill and abortion between ages 18 and 21 significantly increased aggregate cohabitation rates for women in the aged 18-24. An individual level analysis offirst-spouse cohabitation is also conducted. If a woman married between the ages of 18 and 20, the results suggest that access to the pill decreased the likelihood of first-spouse cohabitation. If a woman married between the ages of 21 and 27, early access to the pill had the opposite effect.

The paper reports on the use of the Census Bureau's Public Use Microdata Sample (PUMS) to analyze migration to and from Cleveland- Akron-Lorain Metropolitan Area. Discussion of the PUMS database, its geographic components, and the results of the migration analysis are presented. Thus the purpose is two-fold – to inform the reader about the usefulness of the data and to illustrate its use with a brief descriptive analysis of migration to and from Northeastern Ohio. PUMS data enable the researcher to calculate custom cross-tabulations and summary statistics of population and housing. Among the data available in PUMS is the location of the person five years earlier; for the 2000 Census the data provide the 1995 place of residence and for the American community Survey (ACS) the data provide the residential location one year ago. Thus with the 2000 PUMS data the user can generate the characteristics of persons who moved to a region between 1995 and the 2000 census, whether from other parts of the nation or from abroad. In addition, the user can identify people who lived elsewhere in the United States at the time of the census but reported that they lived in the region in 1995. Thus the researcher can compare movers to and from the region. This database is a rich source of information about where a region draws migration from and where its migrants move to - important knowledge for regional, community, and economic development planning.

Objective. This study explores the entrepreneurial tendencies of Mexican immigrants in metropolitan statistical areas (MSAs) on the U.S. side of the Mexican border vis-a-vis the U.S.-interior. Methods. Using 2000 census data available in the 5% Integrated Public Use Microdata Series, we empirically analyze the self-employment rates and earnings of Mexican immigrants residing in U.S.-cities near Mexico versus those in non-border MSAs. Results. Our findings indicate that Mexican immigrants in MSAs along the U.S.-Mexico border have significantly higher self-employment rates (but lower earnings) than their counterparts in the rest of the United States and non-Hispanic whites in border cities. Explanations for these findings include the existence of trade opportunities in U.S. border cities as well as intense labor market competition that crowds a greater share of immigrants into self-employment. Conclusion. Immigration reform that curtails the immigration flow from Mexico might hinder small business formation and economic development on the U.S. side of the Mexican border.