An algorithm for computing principal points with respect to a loss function in the unidimensional case

In Flury (1990) the k principal points of a random vector X are defned as the points p(1),..., p(k) minimizing EX–p(i)²; i=1,..., k. We extend this concept to that of k principal points with respect to a loss function L, and present an algorithm for their computation in the univariate case.     

Insights from the Evaluation of Past Local Area Population Forecasts

Local area population forecasts have a wide variety of uses in the public and private sectors. But not enough is known about the errors of such forecasts, particularly over the longer term (20 years or more). Understanding past errors is valuable for both forecast producers and users. This paper (i) evaluates the forecast accuracy of past local area population forecasts published by Australian State and Territory Governments over the last 30 years and (ii) illustrates the ways in which past error distributions can be employed to quantify the uncertainty of current forecasts. Population forecasts from the past 30 years were sourced from State and Territory Governments. Estimated resident populations to which the projections were compared were created for the geographical regions of the past projections. The key features of past forecast error patterns are described. Forecast errors mostly confirm earlier findings with regard to the relationship between error and length of projection horizon and population size. The paper then introduces the concept of a forecast ‘shelf life’, which indicates how far into the future a forecast is likely to remain reliable. It also illustrates how past error distributions can be used to create empirical prediction intervals for current forecasts. These two complementary measures provide a simple way of communicating the likely magnitude of error that can be expected with current local area population forecasts.     

Family therapy for drug abuse: review and updates 2003-2010

Just 15 years ago, Liddle and Dakof (Journal of Marital and Family Therapy, 1995; 21, 511) concluded, based on the available evidence, that family therapy represented a "promising, but not definitive" approach for the treatment of drug problems among adolescents and adults. Seven years later, Rowe and Liddle (2003) review described considerable progress in this specialty with encouraging findings on adolescent-focused models based on rigorous methodology, as well as advances with adult-focused family-based treatments. The current review brings the field up to date with highlights from research conducted in the intervening 7 years, cross-cutting issues, recommendations for new research, and practice implications of these findings. Adolescent-focused family-based models that attend to the ecology of the teen and family show the most consistent and strongest findings in recent studies. Adult-focused models based on behavioral and systems theories of change also show strong effects with drug abusers and their families. The overarching conclusion is that family-based models are not only a viable treatment alternative for the treatment of drug abuse, but are now consistently recognized among the most effective approaches for treating both adults and adolescents with drug problems.     

Can a Self-Regulation Skills and Cultural Arts Program Promote Positive Outcomes in Mental Health Symptoms and Academic Achievement for At-Risk Youth?

ABSTRACT

Self-regulation skills programs focusing on emotional regulation and executive functioning and arts programs have separately demonstrated reductions in internalizing and externalizing disorders and academic difficulties and have shown improvement in self-regulation skills. This study sought to evaluate participants in Prodigy (a program synthesizing arts and self-regulation skills) regarding changes in mental health symptoms and academic performance. A quasi-experimental pretest–posttest was conducted with 108 at-risk adolescents and their parents. Significant reductions in internalizing and externalizing mental health symptoms and increases in academic self-efficacy with positive trends in improved academic achievement were noted. Future research regarding the potential of these two modalities is discussed.     

An Empirical Test of the Relative Validity of Expert and Lay Judgments of Risk

This article investigates how accurately experts (underwriters) and lay persons (university students) judge the risks posed by life-threatening events Only one prior study (Slovic, Fischhoff, & Lichtenstein, 1985) has previously investigated the veracity of expert versus lay judgments of the magnitude of risk. In that study, a heterogeneous grouping of 15 experts was found to judge, using marginal estimations, a variety of risks as closer to the true annual frequencies of death than convenience samples of the lay population. In this study, we use a larger, homogenous sample of experts performing an ecologically valid task. We also ask our respondents to assess frequencies and relative frequencies directly, rather than ask for a "risk" estimate--a response mode subject to possible qualitative attributions-as was done in the Slovic et al. study. Although we find that the experts outperformed lay persons on a number of measures, the differences are small, and both groups showed similar global biases in terms of: (1) overestimating the likelihood of dying from a condition (marginal probability) and of dying from a condition given that it happens to you (conditional probability), and (2) underestimating the ratios of marginal and conditional likelihoods between pairs of potentially lethal events. In spite of these scaling problems, both groups showed quite good performance in ordering the lethal events in terms of marginal and conditional likelihoods. We discuss the nature of expertise using a framework developed by Bolger and Wright (1994), and consider whether the commonsense assumption of the superiority of expert risk assessors in making magnitude judgments of risk is, in fact, sensible.     

Substance abuse

Liddle and Dakof's (1995) comprehensive review of the status of family-based treatment for drug abuse concluded that this modality offered a "promising, but not definitive" approach to treating drug abuse among adolescents and adults. Less than a decade later, significant progress can be seen in the treatment of drug abuse problems using family-based approaches, particularly with adolescents. Family-based treatments are currently recognized as among the most effective approaches for adolescent drug abuse. Family-based treatment of adult drug abuse problems has also advanced in important ways with the recent systematic application and testing of engagement techniques and behavioral couples therapy approaches. The current review characterizes and discusses the developmental status of this subspecialty and outlines areas in which continued research attention is needed.     

Sex, ‘race’ and riot in Liverpool, 1919

Racist violence which occurred in Liverpool in 1919 is analyzed in this article, and it is argued that three main themes can be identified in media, policing and political debates which followed. These are fears of sexual relations between different ‘races’, competition for employment, and questions relating to citizenship occasioned by a scheme of assisted repatriation introduced to remove black migrant workers from the ‘mother country’. The article argues that the issue of ‘racial’ difference between the communities involved in the disorders should not be treated as a straightforward variable in its own right. Instead recognition of the articulation between racialised discourse and other factors, such as sexual relations, is central to a full understanding of the events.