Algorithmic parameterization of mixed treatment comparisons

Mixed Treatment Comparisons (MTCs) enable the simultaneous meta-analysis (data pooling) of networks of clinical trials comparing ??2 alternative treatments. Inconsistency models are critical in MTC to assess the overall consistency between evidence sources. Only in the absence of considerable inconsistency can the results of an MTC (consistency) model be trusted. However, inconsistency model specification is non-trivial when multi-arm trials are present in the evidence structure. In this paper, we define the parameterization problem for inconsistency models in mathematical terms and provide an algorithm for the generation of inconsistency models. We evaluate running-time of the algorithm by generating models for 15 published evidence structures.     

Copper mining productivity: Lessons from Chile

Chile represents almost one third of the world’s copper production. Mining is one of the main industries that contributes to our country’s development with resources and is globally recognized. Due to the end of the commodity cycle, improving productivity will be a key variable in mining performance in incoming years. This paper studies mining productivity in Chile by relying on two indicators: measure of the total factor productivity (TFP) using the traditional Solow methodology, and labor productivity. Since 2000, we found a decrease in TFP, explained mainly by the participation of capital as well as diverse factor adjustments to labor and capital inputs. Average labor productivity also decreases 42% from 1999 to 2010, a decrease explained by four determinants: real mining wages, electricity prices, copper prices and mineral grade. Since 2010, average labor productivity has increased 30%, and there is also an opportunity for additional improvement by reducing energy costs as well as by aligning productivity and labor performances.     

Effects of a peer-led AIDS intervention with university students

Acquired immune deficiency syndrome (AIDS) has become a major health threat to university students. This study evaluated a peer-led AIDS intervention program with university students (1) increase knowledge of human immunodeficiency virus (HIV) transmission and infection; (2) change attitudes to reflect scientific information on AIDS-related facts; and (3) change behavioral intentions to correspond with safer sexual practices. Subjects were students (N = 142) from four undergraduate classes and were predominantly female (65%), white (82%), and sexually active (86%). A non-equivalent control group design was used, with two classes receiving the intervention and two classes receiving no information. For the intervention, peer educators presented AIDS-related information, modeled ways to use condoms safely and ways to discuss condom use with sexual partners, and led discussions on HIV infection and use with sexual partners, and led discussions on HIV infection and AIDS, relationships, sexuality, and condom use. A questionnaire was administered to assess differential changes in AIDS-related knowledge, attitudes, and behavioral intentions between the intervention and control groups. The results showed significant improvements among intervention subjects on the knowledge, attitudes, and behavioral intentions scales compared with the control group.     

Projecting age-specific fertility rates by using time-series methods

This paper discusses twostochastic time-series models developed recently for projecting age-specific fertility rates: the CARIMA model and the APC-ARIMA model. The forecasting performance of both models is examined using Dutch data. Alternatively, adeterministic time-series model is presented in which the age pattern of changes in the age-specific fertility rates between successive years is described by a cubic spline function. The model is capable of describing widely varying patterns. The model is applied to age-specific fertility rates for four countries: the Netherlands, England and Wales, Sweden and Australia.Cet article traite de deux modèles stochastiques qui utilisent des séries chronologiques: le modèle CARIMA et le modèle APC-ARIMA qui ont été développés récemment pour projeter les taux de fécondité par âge. La qualité des projections réalisées avec ces deux modèles est testée sur des données hollandaises. Simultanément, un modèle déterministe est présenté dans lequel les changements des taux de fécondité par âge entre années successives sont décrits par une fonction du troisième degré. Ce modèle est capable de décrire des situations qui varient dans un très large domaine. Il est appliqué aux taux de fécondité par âge de quatre pays: la Hollande, l'Angleterre et le Pays de Galles, la Suède et l'Australie.

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The views expressed in this paper are those of the author and do not necessarily reflect the policies of the Netherlands Central Bureau of Statistics.     

Counterphobic behavior in multiply molested children

That multiply molested children are somehow responsible for their victimization is a conclusion unacceptable to the author, who examines one possible cause for the paradoxical behavior of these children.     

Taxation and tax resistance

In recent years social and behavioral sciences have extended their interest to topics not normally thought to be within their province. One of these topics of current interest is tax resistance, an old problem indeed that continues to plague the modern welfare state. People are perfectly willing to benefit from government services but increasingly restive about paying for them. How to cope with this tax-welfare backlash is a crucial problem for all democratic governments. Growing government deficits, for example, may in part be due to the erosion of the tax base which results from a shift to unobserved activities. The main purpose of this article is to offer a theoretical framework for the definition and explanation of tax resistance. To this end, research findings about tax compliance and tax mentality as well as theoretical work on free-riding, exchanging and gift-giving will be presented and discussed.