Using MSA-level panel data on wages and employment, we estimate theimpact of employment density on wages. We find that a doubling of density causes theaverage productivity of labor to increase by between 17 and 28 percent.

The inter-racial marriage gap that opened in the past 50 years is generally attributed to a decline in the availability of young black marriageable men. We contend that the associated shortage of desirable men in the marriage market provides those black men who are sought after with the opportunity to attain a high status spouse, which has placed a premium on black women with lighter skin. We provide evidence, based on data drawn from the Multi City Study of Urban Inequality, consistent with this hypothesis. Our theoretical analysis of the marriage market reveals that marriage promotion policies to increase the desire to marry on the part of young black women will serve to exacerbate the importance attached to skin shade. (c) 2009 Elsevier B.V. All rights reserved.

We measure the extent to which skilled immigrants increase innovation in the United States by exploringindividual patenting behavior as well as state-level determinants of patenting. The 2003 National Surveyof College Graduates shows that immigrants patent at double the native rate, and that this is entirelyaccounted for by their disproportionately holding degrees in science and engineering. These data implythat a one percentage point rise in the share of immigrant college graduates in the population increasespatents per capita by 6%. This could be an overestimate of immigration's benefit if immigrant inventorscrowd out native inventors, or an underestimate if immigrants have positive spill-overs on inventors.Using a 1950-2000 state panel, we show that natives are not crowded out by immigrants, and that immigrantsdo have positive spill-overs, resulting in an increase in patents per capita of about 15% in responseto a one percentage point increase in immigrant college graduates. We isolate the causal effect by instrumentingthe change in the share of skilled immigrants in a state with the initial share of immigrant high schooldropouts from Europe, China and India. In both data sets, the positive impacts of immigrant post-collegegraduates and scientists and engineers are larger than for immigrant college graduates.

In the last decade, historical GIS has emerged as a promising new methodology for studying the past. Historical GIS is the use of geographic information systems software and allied geospatial methods for historical research and teaching. Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship offers case studies and essays on key issues involving historical GIS, highlighting the unprecedented range of tools to visualize historical information in a geographical context. Quantitative social science historians are embracing GIS to facilitate the mapping of large datasets, but anyone with access to the software and the skills to use it can include mapping in research. This change is little short of revolutionary considering how few scholars or students made maps even ten years ago. Historical maps are suddenly in great demand as digitally modified, georeferenced images that enable researchers to study GIS as a visual medium of communication and analysis.

Consistent measures are imperative for conducting valid historical analyses. Collected in the long-form survey of the decennial census, employment data has traditionally been tabulated by aggregate industrial category for all counties. Starting in 2000, the industrial coding scheme drastically changed. In response, we develop a methodology to formulate geographically-sensitive conversion factors that reconfigure NAISC based tabulations into long-established SIC categories.

Recent theoretical and empirical studies have emphasized the fact that the prospect of international migration increases the expected returns to skills in poor countries, linking the possibility of migrating (brain drain) with incentives to higher education (brain gain). If emigration is uncertain and some of the highly educated remain, such a channel may, at least in part, counterbalance the negative effects of brain drain. Moreover, recent empirical evidence seems to show that temporary migration is widespread among highly skilled migrants (such as Eastern Europeans in Western Europe and Asians in the U.S.). This paper develops a simple tractable overlapping generations model that provides an economic rationale for return migration and which predicts who will migrate and who will return among agents with heterogeneous abilities. We use parameter values from the literature and the data on return migration to calibrate our model and simulate and quantify the effects of increased openness on human capital and wages of the sending countries. We find that, for plausible values of the parameters, the return migration channel is very important and combined with the incentive channel reverses the brain drain into significant brain gain for the sending country.

This paper revisits the issue of income convergence by examining the question of whether poorer Census Block Groups have been catching up with wealthier Census Block Groups over the 1980-2000 period. The dataset consists of 161 Census Block Groups in Alabamas west-central Black Belt region. Estimates of a spatial lag model provide support for the conditional convergence hypothesis and explain roughly 60 percent of the variation in income growth. Income growth was positively and significantly correlated with education and employment, and negatively and significantly correlated with majority African-American population.

The U.S. wage structure evolved across the last century: narrowing from 1910 to 1950, fairly stable in the 1950s and 1960s, widening rapidly during the 1980s, and polarizing since the late 1980s. We document the spectacular rise of U.S. wage inequality after 1980 and place recent changes into a century-long historical perspective to understand the sources of change. The majority of the increase in wage inequality since 1980 can be accounted for by rising educational wage differentials, just as a substantial part of the decrease in wage inequality in the earlier era can be accounted for by decreasing educational wage differentials. Although skill-biased technological change has generated rapid growth in the relative demand for more-educated workers for at least the past century, increases in the supply of skills, from rising educational attainment of the U.S. work force, more than kept pace for most of the twentieth century. Since 1980, however, a sharp decline in skill supply growth driven by a slowdown in the rise of educational attainment of successive U.S. born cohorts has been a major factor in the surge in educational wage differentials. Polarization set in during the late 1980s with employment shifts into high- and low-wage jobs at the expense of the middle leading to rapidly rising upper tail wage inequality but modestly falling lower tail wage inequality.

This article analyzes the impact of compulsory schooling laws early in the twentieth century on long-term health. The author finds no compelling evidence for a causal link between education and health using this research design. Further, the results suggest that only a small fraction of health conditions are affected by education, and several of those are conditions, such as sight and hearing, where economic theories don't appear to be relevant.

This paper estimates the effects of immigration on wages of native workers at the national U.S. level. Following Borjas (2003) we focus on national labor markets for workers of different skills and we enrich his methodology and refine previous estimates. We emphasize that a production function framework is needed to combine workers of different skills in order to evaluate the competition as well as cross-skill complementary effects of immigrants on wages. We also emphasize the importance (and estimate the value) of the elasticity of substitution between workers with at most a high school degree and those without one. Since the two groups turn out to be close substitutes, this strongly dilutes the effects of competition between immigrants and workers with no degree. We then estimate the substitutability between natives and immigrants and we find a small but significant degree of imperfect substitution which further decreases the competitive effect of immigrants. Finally, we account for the short run and long run adjustment of capital in response to immigration. Using our estimates and Census data we find that immigration (1990-2006) had small negative effects in the short run on native workers with no high school degree (-0.7%) and on average wages (-0.4%) while it had small positive effects on nativeworkers with no high school degree (+0.3%) and on average native wages (+0.6%) in the long run. These results are perfectly in line with the estimated aggregate elasticities in the labor literature since Katz and Murphy (1992). We also find a wage effect of new immigrants on previous immigrants in the order of negative 6%.Keywords: Less Educated Workers, Physical Capital Adjustment, Skill Complementarities, WagesJEL Classifications: F22, J31, J61

This paper reviews the major social and demographic forces influencing American fertility levels with the aim of predicting changes during the next three decades. Increases in the Hispanic population and in educational attainment are expected to have modest and offsetting effects on fertility levels. A cessation of the recent pattern of increasing ages at childbearing will at some point put upward pressure on period (but not cohort) fertility rates. Higher relative wages for women and better contraception have empowered women and fundamentally altered marriage and relations between the sexes. But women's childbearing has become less dependent upon stable relations with men, and educational differences in intended fertility have narrowed. One explanation of higher fertility in the U.S. than in other developed countries is that its institutions have adapted better to rising relative wages for women and the attendant increase in women's labor force participation.

For marketers, television remains the most important advertising medium. This paper proposes a two-sided model of the television industry. We estimate viewer demand for programs on one side, and advertiser demand for audiences on the other. The primary objective is to understand how each group's program usage influences the other group.Four main conclusions emerge. First, viewers tend to be averse to advertising. When a highly-rated network decreases its advertising time by 10%, our model predicts a median audience gain of about 25% (assuming no competitive reactions). Second, we find the price elasticity of advertising demand is ?2.9, substantially more price-elastic than 30 years ago.Third, we compare our estimates of advertiser and viewer preferences for program characteristics to networks' observed program choices. Our results suggest that advertiser preferences influence network choices more strongly than viewer preferences. Viewers' two most preferred program genres, Action and News, account for just 16% of network program hours. Advertisers' two most preferred genres, Reality and Comedy, account for 47% of network program-hours.Fourth, we perform a counterfactual experiment in which some viewers gain access to a hypothetical advertisement-avoidance technology. The results suggest that ad-avoidance tends to increase equilibrium advertising quantities and decrease network revenues.Keywords: Advertising, Broadcasting, Demand Estimation, Empirical Industrial Organization, Endogeneity, Entertainment Marketing, Media, Television, Two-Sided MarketsJEL Classifications: C10, C21, C35, C51, D12, D43, L13, L82, M31, M37

A single search interface to all a person’s digital resources, such as email archives, corporate databases, websites, and subscription services, is appealing but a central index of all private, corporate, subscription and web data is impractical. A metasearch approach can instead integrate any number of existing search services over a variety of data. This thesis advocates and examines personal metasearch, or metasearch over a user’s entire set of digital resources. Metasearch has been well studied in other environments, but has not before been considered with this range of resources; therefore several aspects are re-examined in this new application. Experiments in document sampling, collection size estimation, language modelling, and server selection, all important subproblems in metasearch, demonstrate that established techniques which work well in traditional settings do not necessarily operate well over the wide range of resources in personal applications. Many techniques for sampling documents from a collection are biased, especially towards longer documents; other metasearch subproblems often rely on unbiased samples and their performance is adversely affected. A new technique for generating samples is therefore proposed and evaluated, and results indicate improvements in sample quality. Techniques for collection size estimation, language modelling, and server selection are also investigated in a personal metasearch framework. Several techniques prove inappropriate or have been over-fitted in earlier work, but some appear useful. In each case, performance is improved with better-quality samples of documents as input. Finally, standard evaluation techniques are a poor fit to the personal metasearch environment, and this thesis proposes a new method based on a functioning search tool inserted into the natural retrieval process. This allows study of real information needs, works with dynamic and/or private collections, and records judgements in their full context. It has been validated in a number of experiments and used with a working personal metasearch tool to compare methods for server selection. Contributions of this thesis include the first analysis of personal metasearch, from a theoretical basis and from studies of potential users; a new algorithm for document sampling which is better able to operate over the wide variety of data sources found in this application; an evaluation of a number of metasearch algorithms and an analysis of common failures; an evaluation technique suited to personal and dynamic collections; and a platform for further research.

Social capital theory suggests that individuals can access resources through their relationships with others. While research in this area typically focuses on the potential benefits of having high-status network alters, the authors emphasize that relationships with experts, in particular, provide access to specialized knowledge. Expertise may be accessed through formal, contractual means. But individuals who have an expert within their network of close family and friends may benefit from more convenient and lower cost expertise. The authors explore the prevalence and nature of expert contacts within individuals' social networks using data from the 1985 and 2004 General Social Surveys. About a quarter of Americans identify an expert among their network contacts. Racial minorities and members of the lower- and working-classes have less access to experts within their personal networks, however, and minorities have become particularly disadvantaged over the past two decades in terms of both overall and informal access to expertise. The authors urge further research to examine the causes of disparities in social network ties to experts and their implications for processes of social stratification.

The literature indicated that tuition and fee prices influenced enrollment in postsecondary education, with higher prices resulting in decreased attendance. The difference in tuition and fees between public community colleges and undergraduate institutions, operationalized as the tuition and fee difference ratio, was examined for its association with enrollment. The purpose of this study was to test student price response theory by examining the degree to which the attempt to provide access to public postsecondary education via the introduction of a lower-priced option, with considerations of a state’s resources, was associated with enrollment for the years 1960, 1970, 1980, 1990 and 2000. Results indicated that the difference in tuition and fees was not statistically significantly related to enrollment. The general trend of the tuition and fee difference ratio was, however, negatively associated with enrollment. Implications for state systems were discussed.

In 1955 fewer than 2% of the nation's residences had air conditioning; by 1980 over half were air conditioned, and over a quarter had central air. This paper attempts to explain the growth and the geographic differences in the prevalence of residential air conditioning from the mid fifties to 1980. Census data and data on climate and relevant prices are combined to estimate a model that focuses on the role of economic factors, that is, geographic differences and changes over time in incomes and prices, in affecting the pattern of diffusion of residential air conditioning. (C) 2008 Elsevier Inc. All rights reserved.

In this paper we introduce a new way to conceptualize and measure the educational resources that young people encounter as they make their way from kindergarten to high school graduation. Using recent methodological advances in group-based modeling and a unique data set, we empirically test for and identify a series of categorically distinct school quality trajectories. We find that these trajectories vary significantly in terms of their intercept and slope, their prevalence within the sampled population, and in the sociodemographic makeup of their constituent members. We then present an extended empirical example illustrating relationships between school quality trajectories and important post-secondary educational outcomes, both before and after controlling for static, single-year measures of primary and secondary school characteristics. Our results suggest that the chronology of students exposures to different educational resources is significantly associated with college enrollment, college selectivity, and, in some instances, college completion.

The growth of the prison system over the last three decades represents a critical institutional intervention in the lives of American families. The massive buildup in the size of the penal population has not been due to large scale changes in crime or criminality. Instead, a host of changes at the local, state, and federal levels with respect to law enforcement and penal policy are implicated in the expansion of the prison system. Such a dramatic change in criminal justice policy – and rapid growth in the prison system – raises questions about its demographic effects. In this paper we combine data on the non-institutionalized population with data from surveys of inmates to examine the demographic implications of the prison boom. The massive growth of the penal system is notable not only for its size, but also for its disproportionate effects on minority and low-skill men. Results indicate that growth in the prison population over the past 30 years has been accompanied by low fertility, high morbidity due to communicable diseases, and high rates of involuntary population mobility among inmates and expansion of the prison system obscures the extent of racial inequality in demographic outcomes. We argue that the prison boom marks a “third demographic transition” representing growing institutional involvement in the lives of disadvantaged Americans