From an evolutionary point of view, it is difficult to explain the existence of altruism that is not directed at kin or at friends. But humans demonstrate this form of altruism commonly, in such ways as donating to charity or heroically saving another's life. One explanation of these behaviours that is still consistent with evolutionary theory is the idea that altruism may function as a signal. Altruists gain a positive reputation through their deeds that may ultimately return to increase their biological fitness. Here I test this idea in a variety of ways, focusing on altruism as a signal of status. In the laboratory, I conducted an experiment where participants had the incentive to signal their personal wealth to others. In another experiment, I manipulated participants' relative status in an attempt to reduce costly conflict between participants. Outside the laboratory, I investigated the connection between heroism and reproductive success through a sample of WWI heroes. The background, methods, and conclusions of these studies are detailed within.

We assess whether adolescents who faced a higher risk of having been aborted are more likely to use controlled substances. We find that adolescents born in states that legalized abortion before national legalization in 1973, during the years when only those states permitted abortion, were much less likely to use drugs than persons from the same birth cohorts born elsewhere. These differences do not exist for earlier or later cohorts. Our results are much the same when we characterize abortion risk by either the birth rate or abortion rate in the year and place of the person's birth.

Using data spanning a half century for adjacent jurisdictions in the U.S. and Canada, we study the long-term effects of a very generous unemployment insurance (UI)program on weeks worked. We find large effects. For example, in 1990, about 6 percent of employed men in Maine's northernmost counties worked fewer than 26 weeks per year; just across the border in New Brunswick that figure was over 20 percent. According to our estimates, New Brunswick's much more generous UI system accounts for about two thirds of this differential. Even greater effects are found among women and less-educated men. We argue that our longer-run, cross-national perspective generates more substantial estimates of program effects because it captures workers' abilities to make a wider variety of adjustments to programs they expect to be permanent.

We review the empirical literature on ethnic enclave after the concept was formulated twenty-five years ago. The balance of this literature is mixed, but many studies reporting negative conclusions were marred by faulty measurement of the concept. We discuss the original theoretical definition of enclaves, the hypothesis derived from it, and the difficulties in operationalizing them. for evidence, we turn to census data on the location and the immigrant group that gave rise to the concept in the first place--Cubans in Miami. We examine the economic performance of this group, relative to others in this metropolitan area, and in the context of historical changes in its own mode of incorporation. Taking these changes into account, we find that the ethnic enclave had a significant economic payoff for its founders--the earlier waves of Cuban exiles--and for their children, but not for refugees who arrived in the 1980 Mariel exodus and after. Reasons for this disjuncture are examined. Implications of these results for enclave theory and for immigrant entrepreneurship in general are discussed.

The Comparable Wage Index (CWI) is a measure of the systematic, regional variations in the salaries of college graduates who are not educators. It can be used by researchers to adjust district-level finance data at different levels in order to make better comparisons across geographic areas. The CWI was developed by Dr. Lori L. Taylor at the Bush School of Government and Public Service, Texas A&M University and William J. Fowler, Jr. at NCES. Dr. Taylor's research was supported by a contract with the National Center for Education Statistics. The complete description of the research is provided in the NCES Research and Development "A Comparable Wage Approach to Geographic Cost Adjustment" (NCES 2006-321). This documentation describes four geographic levels of the CWI, which are presented in four separate files. These files are the school district, labor market, state, and a combined regional and national file. The school district file provides a CWI for each local education agency (LEA) in the NCES Common Core of Data (CCD) database. For each LEA there is a series of indexes for the years 1997-2004. The file can be merged with school district finance data, and this merged file can be used to produce finance data adjusted for geographic cost differences. This file also includes four agency typology variables. The additional files allow for similar geographic cost adjustments for larger geographic areas. NCES has sponsored the development of other geographic adjustment indexes in the past; the latest was for the 1993-94 school year. The following are appended: (1) Record Layout and Descriptions of Data Elements: NCES District CWI Data File; (2) Record Layout and Descriptions of Data Elements: NCES Labor Market CWI Data File; (3) Record Layout and Descriptions of Data Elements: NCES State CWI Data File; (4) Record Layout and Descriptions of Data Elements: NCES Regional CWI Data File; (5) Glossary; and (6) Frequencies and Ranges. (Contains 2 tables, 6 footnotes, and 1 figure.)

This paper studies the economics of match formation using a novel data set obtained from a major online dating service. Using detailed information on the users' attributes and interactions, we estimate a model of mate preferences. We use the Gale-Shapley algorithm to compute the (man-and woman-optimal) stable matches generated by the estimated preferences, and find that they are similar to the matches observed online. We then explore whether the estimated mate preferences, in conjunction with the Gale-Shapley algorithm, can explain assortative mating patterns in "offline" marriages. We conclude that the estimated mate preferences can generate assortative mating patterns similar to those observed in marriages even in the absence of search frictions.

Understanding the evolution of the skill premium is important to understand both the evolution of inequality among workers of different qualifications and the characteristics of the development process of a country. In this paper, I use sectoral and macro data for Chile and the US to explain the evolution of the relative demand for skilled labor in Chile in the context of a model of endogenous technological choice where new technologies are developed in the US and adopted in Chile. Macro and sectoral evidence confirm the main theoretical predication of the model: patterns of skill upgrading in Chile have followed the evolution of the same variable in the US.

When making references to their historical origin, it is not at easy to distinguish the one of statistics from the one of demography. This is nevertheless not the only reason for which, in the Italian academic and scientific tradition (similarly to other, but not to all, traditions), demography has been considered as part of the general family of statistical sciences. Italian demography thus actively contribute to . . .

The combined influence of the Great Migration of African Americans and the civil rights movement propelled the drive for fair housing legislation, which attempted to curb overt discrimination in housing markets. This drive culminated in the federal Fair Housing Act of 1968. By that time, 57 percent of the U.S. population and 41 percent of the African American population already resided in states with a fair housing law. This article uses hazard models to analyze the diffusion of state fair housing legislation and to shed new light on the combination of economic and political forces that facilitated the laws' adoption. Outside the South, states with larger union memberships, more Jewish residents, and more NAACP members passed fair housing laws sooner than others. Including controls for a variety of competing factors does not undermine the estimates, and historical accounts of the legislative campaigns support the article's interpretation.

The role of linguistic enclaves in wage determination is investigated for immigrants and non-immigrants. It is hypothesized that enclaves could affect wages positively as an aid to immigrant adjustment, or negatively as an amenity that minority language speakers are willing to pay for, or both. The results suggest that enclaves in the Southwest U.S. primarily operate as an aid to immigrant adjustment.

Although movement to new and unfamiliar places is prominent in the conceptualization of migration, few studies have focused resolutely on this form of migration, referred to as onward migration. A larger body of research is focused on return migration, or the movement back to familiar places. This study utilizes the NLSY79 to build on the earlier panel based investigation of repeat migration by DaVanzo and Morrison, whose data did not allow for analysis of possible racial/ethnic differences in forms of repeat migration. Multivariable logistic regression is utilized to compare rates of onward migrations for Hispanics, non-Hispanic blacks and non-Hispanic whites while controlling other socioeconomic and demographic variables. The most important finding of this study is significantly lower rates of onward migration for blacks and Hispanics than for whites.

OBJECTIVES This study assessed the extent to which working various types of nonstandard shift schedules (eg, night and evening shifts) is associated with the risk of occupational injuries or illnesses. METHODS Multivariate analyses were conducted using data from 13 years (1987 to 2000) of the National Longitudinal Survey of Youth (NLSY) encompassing 110 236 job records and over 82 000 person-years of work experience. Cox proportional hazard regression techniques were used to derive hazard ratios comparing the relative risk of suffering a work-related injury among people working night, evening, rotating, split, and irregular shifts to the risks for those working conventional day shifts, after adjustment for age, gender, occupation, industry, and region. Incidence rates were normalized using a common denominator of 100 person-years of "at-risk time" to obtain valid comparisons. RESULTS All of the nonstandard shift schedules, except split shifts, were found to have a higher risk for occupational injuries and illnesses than conventional day shifts. After control for the selected covariates, the calculated hazard ratios were 1.43 for evening shifts [95% confidence interval (95% CI) 1.26-1.62], 1.36 for rotating shifts (95% CI 1.17-1.58), 1.30 for night shifts (95% CI 1.12-1.52), 1.15 for irregular shifts (1.03-1.30), and 1.06 for split shifts (0.71-1.58). CONCLUSIONS These findings suggest that nonstandard shifts are not more risky merely because of the concentration of hazardous jobs in those types of schedules or because of underlying differences in the characteristics of employees working nonstandard shifts. The results point to the need to extend targeted injury prevention programs not only to people working night shifts, but also to those who work evenings.

Where the poor live and why has an enormous impact on access to jobs, decent quality schools, and other local attributes that affect a familys ability to rise up out of poverty. Low-income families also rely disproportionately on rental housing for their accommodations. Accordingly, because rental housing support programs affect the location opportunities for the poor, it is important to consider the broader set of factors that drive where poor neighborhoods are found. Failure to do so could undermine the effectiveness of well-intended initiatives. With that in mind, this paper provides a framework and evidence that helps to characterize where poor neighborhoods tend to be found, and why. Results indicate that many neighborhoods exhibit considerable persistence in poverty levels over the 1970 to 2000 period, but many other neighborhoods do not. Persistence is by far the highest among communities with poverty rates below 15 percent: roughly 80 percent of these communities retain their low poverty status between 1970 and 2000. Other neighborhoods however, display much less persistence. Among very high poverty tracts (tracts with over 40 percent poverty), persistence between 1970 and 2000 is just 43 percent. Thus, over half of the highest poverty neighborhoods in 1970 were of lower poverty status thirty years later.What contributes to this variety of experience? Further analysis in the paper suggests that change in local poverty rates arise from four very different mechanisms: access to public transit, the presence of aging housing stocks, local spillover effects arising from social interactions, and the presence of place-based subsidized rental housing (i.e. public and LIHTC housing). Together, these factors explain a considerable portion of the one-decade ahead change in census tract poverty rates. However, on balance, it is still difficult to anticipate where the poor will live several decades out into the future. Yet place-based subsidized housing is both spatially fixed and long lived. For that reason, at least with respect to implications for location opportunities, flexible tenant-based rental housing support programs appear to offer advantages.

The black-white earnings gap has historically been larger in the South than in other regions of the United States. Since 1970, however, the male annual earnings gap outside the South has increased dramatically, when the analysis factors in non-participants while the gap within the South has narrowed, to the point where 2000 Census figures indicate significantly lower racial inequality in the South. Three proposed explanations for this trend focus on changing patterns of selective migration, labor market trends including reduced discrimination and the decline of manufacturing employment, and reductions in school segregation and school resource disparities in the South relative to the North. Evidence suggests that selective migration can explain about 40% of the Souths relative advance, and virtually all of the relative advance after 1980. Earlier declines can be attributed in large part to reduced industrial segregation and other labor market advances in the South. Relative improvements in school quality for Southern blacks explain at most 20% of the overall trend.

Utilizando la muestra censal del 5% de los IPUMS-U.S. 2000 y modelos de regresión logística, este trabajo explora los factores que afectan la participación económica de las mujeres mexicanas y las centroamericanas residentes en Estados Unidos en el año 2000. Este estudio intenta demostrar que existen distintos patrones de participación económica para mujeres centroamericanas y mexicanas pese a que ambos grupos poseen características sociodemográficas similares. Se espera comprobar que en mujeres de primera generación (ambos grupos), las características de la comunidad de destino influyen en mayor medida que las individuales en la participación económica, por lo que se asumirá que estarán sólo incorporadas, mientras que aquellas en las que el peso de la dimensión individual favorece la participación económica (generación 1.5), probablemente experimenten un proceso de asimilación a la sociedad estadounidense y su patrón de participación económica será similar al grupo más representativo (mujeres blancas no hispanas nativas).