The effect of immigrant admission criteria on immigrant labour-market characteristics

The skill levels of immigrants entering the USA has declined in recent decades; however, most immigrants to the USA continue to be admitted on the basis of family contacts, without reference to labour-market characteristics. This situation has given rise to a debate about the criteria on which immigrants are admitted or excluded. I examine how the relative skill levels of immigrants admitted under different criteria vary by country of origin, those criteria being the possession of highly-valued skills and family connections. Using data from the Immigration and Naturalization Service, Borjas' 1987 model is tested. The results show (a) that the relative skill levels of the two groups do indeed differ by country of origin, and (b) the pattern by country of origin is consistent with the Borjas predictions. The policy implication is that the effects of changing admission criteria will differ by country of origin, but in a predictable way.     

Betting on Illusory Patterns: Probability Matching in Habitual Gamblers

Why do people gamble? A large body of research suggests that cognitive distortions play an important role in pathological gambling. Many of these distortions are specific cases of a more general misperception of randomness, specifically of an illusory perception of patterns in random sequences. In this article, we provide further evidence for the assumption that gamblers are particularly prone to perceiving illusory patterns. In particular, we compared habitual gamblers to a matched sample of community members with regard to how much they exhibit the choice anomaly ‘probability matching’. Probability matching describes the tendency to match response proportions to outcome probabilities when predicting binary outcomes. It leads to a lower expected accuracy than the maximizing strategy of predicting the most likely event on each trial. Previous research has shown that an illusory perception of patterns in random sequences fuels probability matching. So does impulsivity, which is also reported to be higher in gamblers. We therefore hypothesized that gamblers will exhibit more probability matching than non-gamblers, which was confirmed in a controlled laboratory experiment. Additionally, gamblers scored much lower than community members on the cognitive reflection task, which indicates higher impulsivity. This difference could account for the difference in probability matching between the samples. These results suggest that gamblers are more willing to bet impulsively on perceived illusory patterns.     

The geographic scale of Metropolitan racial segregation

This article addresses an aspect of racial residential segregation that has been largely ignored in prior work: the issue of geographic scale. In some metropolitan areas, racial groups are segregated over large regions, with predominately white regions, predominately black regions, and so on, whereas in other areas, the separation of racial groups occurs over much shorter distances. Here we develop an approach—featuring the segregation profile and the corresponding macro/micro segregation ratio—that offers a scale-sensitive alternative to standard methodological practice for describing segregation. Using this approach, we measure and describe the geographic scale of racial segregation in the 40 largest U.S. metropolitan areas in 2000. We find considerable heterogeneity in the geographic scale of segregation patterns across both metropolitan areas and racial groups, a heterogeneity that is not evident using conventional “aspatial” segregation measures. Moreover, because the geographic scale of segregation is only modestly correlated with the level of segregation in our sample, we argue that geographic scale represents a distinct dimension of residential segregation. We conclude with a brief discussion of the implications of our findings for investigating the patterns, causes, and consequences of residential segregation at different geographic scales.     

Consistent Nonparametric Tests for Lorenz Dominance

This article proposes consistent nonparametric methods for testing the null hypothesis of Lorenz dominance. The methods are based on a class of statistical functionals defined over the difference between the Lorenz curves for two samples of welfare-related variables. We present two specific test statistics belonging to the general class and derive their asymptotic properties. As the limiting distributions of the test statistics are nonstandard, we propose and justify bootstrap methods of inference. We provide methods appropriate for case where the two samples are independent as well as the case where the two samples represent different measures of welfare for one set of individuals. The small sample performance of the two tests is examined and compared in the context of a Monte Carlo study and an empirical analysis of income and consumption inequality.     

Occupational stress,rescue workers and English law

Abstract

This paper shows how two strands of English case law, one establishing liability to compensate for shock suffered by those at the scene of disaster, and the other concerned with physical injury suffered by rescuers, were brought together in the 1960s to provide a remedy for a rescuer suffering from what the law describes as ‘nervous shock’. It further traces the development of employers' liability in this context, but finds that the law provides few examples of the contractual duty of employers to protect employees generally against stress that may cause psychological injury. It points out that there is no case law on the liability of employers for stress suffered by rescue workers, whether professional or otherwise. It notes that law reports give little guidance as to the medical evidence judges require to persuade them that nervous shock has been suffered. Finally, it spells out that EC-inspired regulations could now be used to require employers to assess, and take steps to control, stress to which their employees, including rescue workers, are exposed.     

In-stream habitat predicts salamander occupancy and abundance better than landscape-scale factors within exurban watersheds in a global diversity hotspot

Urban Ecosystems - The southern Appalachian Mountains have experienced rapid human population growth rates since the 1980s. Land used practices are shifting from rural to residential. The majority...     

Ethical Issues in Disaster Research: Lessons from Hurricane Katrina

Conducting research in the wake of a catastrophic event imposes the dual responsibilities on researchers of protecting the rights of the survivors as research subjects, while also ensuring research quality and the dissemination and application of findings. This article, based partially on the authors’ experiences of conducting research in school districts following Hurricane Katrina, examines the ethical issues that arise when working with survivors, reticent organizations, and institutional review boards. Challenges experienced by researchers concerning access, informed consent, confidentiality, subject compensation, and enlisting the assistance of stressed institutions are described. This material is based upon work supported by the National Science Foundation under Grant No. 0036566000. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.     

An Infinite Decision Puzzle

We tell a story where an agent who chooses in such a way as to make the greatest possible profit on each of an infinite series of transactions ends up worse off than an agent who chooses in such a way as to make the least possible profit on each transaction. That is, contrary to what one might suppose, it is not necessarily rational always to choose the option that yields the greatest possible profit on each transaction.     

A note on exact calculation of the non central hypergeometric distribution

Direct calculation of the non central hypergeometric (NH) distribution and its moments can present computational issues in both efficiency and accuracy. In response, several methods, both approximate and exact, for calculating the NH mean and variance have appeared in the literature. We add to this body of work, a straight-forward, exact method that is easily programed, efficient, and computationally stable. Specifically, by considering the logs of the values of the NH probability mass function (pmf) and then shifting the exponents so that, prior to normalization, the mode acquires a value of 1, concerns for overflow are eliminated.