VaR without correlations for portfolios of derivative securities

We propose filtering historical simulation by GARCH processes to model the future distribution of assets and swap values. Options’ price changes are computed by full reevaluation on the changing prices of underlying assets. Our methodology takes implicitly into account assets’ correlations without restricting their values over time or computing them explicitly. VaR values for portfolios of derivative securities are obtained without linearising them. Historical simulation assigns equal probability to past returns, neglecting current market conditions. Our methodology is a refinement of historical simulation. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 583–602, 1999     

Integrating the environmental and economic consequences of converting to organic agriculture: evidence from a case study

In the current debate about the future of food quality, the merits of organic agriculture are frequently championed, but few studies have sought to integrate the changes in soil conditions, biodiversity and socio-economic welfare linked to the conversion from non-organic to organic production. This article aims to undertake this approach with respect to one case study. Its conclusions may not be representative for all organic conversions, but the findings are of relevance at a time of debate over changing patterns of subsidies and other incentives in agricultural policy. The study showed that there were demonstrable differences in overall environmental conditions in the comparison of organic and non-organic farming, with field evidence of increased species diversity, and an eventual improvement in the profitability of the organic farming regime. The broad conclusion is that there are definite environmental and economic advantages arising from organic agriculture that are not fully reflected in the present pattern of agricultural incentives. The study also showed that variations in farm management practice strongly influence the notion of on-farm and off-farm environmental consequences. The implications of these findings for the future of sustainable agriculture and for interdisciplinary science are also discussed.     

PHYSICAL STATURE IN NINETEENTH‐CENTURY NEW ZEALAND: A PRELIMINARY INTERPRETATION

During the late nineteenth century, the physical stature of New Zealand‐born men stagnated, despite an apparently beneficial public health environment and growth in per‐capita incomes. We examine trends and differentials in male stature through World War I enlistment and casualty records. Stature varied by social class, with professionals and men in rural occupations substantially taller than their peers. There is not enough evidence to show that the indigenous Maori population differed in height from men of European descent. Stagnation in stature in late nineteenth‐century New Zealand is consistent with patterns observed in Australia, North America, and Western Europe.     

Parenting Orientations as Antecedents of Children's Violent Videogame Play

The study investigates caregiver influence on children's playing of violent videogames. Based on theory, the investigation develops and tests a model that links parental socialization tendencies to children's violent videogame play. Results from a national sample of 237 caregiver–child dyads suggest that while the primary caregivers' tendencies toward warmth and restrictiveness likely lessen children's play levels of violent videogames, their predispositions toward anxious emotional involvement tend to increase play. Moreover, results suggest that these relationships are mediated by caregiver mediation of videogames.     

The adoption and impact of engineering‐type measures to address climate change: evidence from the major grain‐producing areas in China

Employing an endogenous switching regression model, we investigate the drivers underlying the adaptations made by farm households and their impacts on crop net incomes for adopters and nonadopters, based on a large panel survey data set across the major grain‐producing provinces in China. The results show that: (i) access to public climate information and technical or physical support increases the likelihood that farmers adapt to climate change by undertaking irrigation and/or drainage measures; and (ii) decisions to adapt increased crop yield, but they did not significantly increase crop profit margins. This point appears to have been ignored by previous studies. Based on these new empirical results, the paper suggests that government should continue to provide climate information and various types of supports to improve farmers’ adaptation abilities and help to reduce the levels of factor input by, for example, substituting organic for chemical fertiliser inputs. Such government‐led policies should be supported alongside the implementation of domestic agricultural supply‐side reform.     

TEN THINGS WE SHOULD KNOW ABOUT TIME SERIES

Abstract Time series data affect many aspects of our lives. This paper highlights 10 things we should all know about time series, namely, a good working knowledge of econometrics and statistics, an awareness of measurement errors, testing for zero frequency, seasonal and periodic unit roots, analysing fractionally integrated and long memory processes, estimating VARFIMA models, using and interpreting cointegrating models carefully, choosing sensibly among univariate conditional, stochastic and realized volatility models, not confusing thresholds, asymmetry and leverage, not underestimating the complexity of multivariate volatility models, and thinking carefully about forecasting models and expertise.     

A regional model of endogenous growth without scale assumptions

In this paper we model growth using a scale-neutral approach to innovation allowing differences between regions to emerge due to regional mechanisms. In this model, agglomeration is growth enhancing as the scale effect for innovation arises from greater access to knowledge rather than any assumed scale effects in growth-modelling techniques. Furthermore, entrepreneurs are assumed to choose the location of firms endogenously so as to minimize the costs of innovation, transport and living. The effects of such mechanisms are such that any policies that increase knowledge spillovers between locations will enhance growth and equality, but may be destabilizing for agglomeration.     

Beyond Deception: Potential Unfair Consumer Injury from Various Types of Covert Marketing

Although there is little agreement over the best definition or even name for covert marketing, many policymakers and commentators agree that covert marketing may deceive consumers to their detriment. This study proposes that some forms of covert marketing also impose a type of unavoidable consumer injury that we call marketer control of consumer engagement. This injury, if aggregated to be substantial, can violate legal prohibitions against unfair acts and practices. To reach this conclusion, this study first proposes a name mnemonic and then develops a typology of covert marketing practices that may deceive and also unfairly injure consumers. It concludes by discussing policy implications of this two‐ rather than one‐dimensional analysis of covert marketing.