Combining forecast quantiles using quantile regression: Investigating the derived weights, estimator bias and imposing constraints

SUMMARY A novel proposal for combining forecast distributions is to use quantile regression to combine quantile estimates. We consider the usefulness of the resultant linear combining weights. If the quantile estimates are unbiased, then there is strong intuitive appeal for omitting the constant and constraining the weights to sum to unity in the quantile regression. However, we show that suppressing the constant renders one of the main attractive features of quantile regression invalid. We establish necessary and sufficient conditions for unbiasedness of a quantile estimate, and show that a combination with zero constant and weights that sum to unity is not necessarily unbiased.     

Workshop to Orient Students to Career Planning Services

This article describes a 1-hour workshop designed to orient students to a career resource center and assist them with career decision making.     

A sociology of hackers

Illicit computer intruders, or hackers, are often thought of as pathological individuals rather than as members of a community. However, hackers exist within social groups that provide expertise, support, training, journals and conferences. This article outlines this community to establish the nature of hacking within ‘information societies’. To delineate a ‘sociology of hackers’, an introduction is provided to the nature of computer–mediated communication and the act of computer intrusion, the hack. Following this the hacking community is explored in three sections. First, a profile of the number of hackers and hacks is provided by exploring available demographics. Second, an outline of its culture is provided through a discussion of six different aspects of the hacking community. The six aspects are technology, secrecy, anonymity, membership fluidity, male dominance and motivations. Third, an exploration of the community's construction of a boundary, albeit fluid, between itself and its other, the computer security industry, is provided. This boundary is constructed through metaphors whose central role is to establish the ethical nature of hacking. Finally, a conclusion that rejects any pathologisation of hackers is offered.     

Feminist Criminology: Gain, Loss and Backlash

Surviving the inevitable process of innovation, critique and response that accompanies conceptual invention, feminist criminology is now a rich and diverse field of scholarship and political activism. This article follows the main threads of feminist criminological thought (empirical, standpoint and post-modern), outlining the tensions and connections between each. I then consider the political ground gained and lost by feminist criminologists, paying careful attention to the ways in which feminist ideas have been co-opted by governing authorities and also considering the current climate of backlash against feminist ideas in both criminal justice policy and the academy.     

Acculturation and Risk Behavior among Pregnant Mexican American Females: A Structural Equation Model

The purpose of this study was to test a theoretical model designed to predict risk behavior (i.e., cigarette and/or alcohol use) in a sample of Mexican American females who were pregnant and ranged in age from adolescence to early adulthood. The model consisted of six hypothesized predictors–acculturation status, intergenerational family conflict, acculturative stress, educational attainment, household income, and age of respondent, which were proposed as antecedents of risk behavior. Structural equation modeling was used to test both the direct and indirect effects for a set of proposed antecedents to the tendency for Mexican American females to engage in risk behaviors. Several of the hypothesized relationships were supported, with the strongest predictors of risk behavior being acculturation status, intergenerational family conflict, and acculturative stress. An important conclusion was that risk behavior by Mexican American females increased as they became more acculturated to the social circumstances of the U.S. Another notable result was that risk behavior increased among Mexican American females as they experienced higher levels of intergenerational conflict within their families.     

Cybersex: The Impact of a Contemporary Problem on the Practices of Marriage and Family Therapists

The number of people accessing the Internet for sexual purposes (cybersex) has increased dramatically over the last 10 years. However, little research has been conducted to determine how frequently clients present for treatment with cybersex‐related issues. One hundred sixty‐four clinical members of the American Association for Marriage and Family Therapy participated in the current study, which was conducted to identify the impacts of cybersex on MFTs’ practices. Most respondents report seeing clients with cybersex‐related issues, with client numbers increasing over the past 2 years. Although most respondents felt prepared to diagnose and treat adults with cybersex problems, half felt unprepared to diagnose and treat children. Lastly, most respondents reported that their required college courses were not helpful in preparing them to diagnose and treat cybersex‐related problems. The implications of study findings are discussed.     

An Evaluation of a Child Guidance Clinic

An attempt is made to evaluate the effectiveness of a child guidance clinic. The outcome of the clinic's intervention was found to vary according to the nature of the presenting problem and the social class of the client. The categories of problems where treatment was ineffective are discussed in detail.     

Random regression models for human immunodeficiency virus ribonucleic acid data subject to left censoring and informative drop-outs

Objectives in many longitudinal studies of individuals infected with the human immunodeficiency virus (HIV) include the estimation of population average trajectories of HIV ribonucleic acid (RNA) over time and tests for differences in trajectory across subgroups. Special features that are often inherent in the underlying data include a tendency for some HIV RNA levels to be below an assay detection limit, and for individuals with high initial levels or high ranges of change to drop out of the study early because of illness or death. We develop a likelihood for the observed data that incorporates both of these features. Informative drop-outs are handled by means of an approach previously published by Schluchter. Using data from the HIV Epidemiology Research Study, we implement a maximum likelihood procedure to estimate initial HIV RNA levels and slopes within a population, compare these parameters across subgroups of HIV-infected women and illustrate the importance of appropriate treatment of left censoring and informative drop-outs. We also assess model assumptions and consider the prediction of random intercepts and slopes in this setting. The results suggest that marked bias in estimates of fixed effects, variance components and standard errors in the analysis of HIV RNA data might be avoided by the use of methods like those illustrated.