Variance estimation when donor imputation is used to fill in missing values

Donor imputation is frequently used in surveys. However, very few variance estimation methods that take into account donor imputation have been developed in the literature. This is particularly true for surveys with high sampling fractions using nearest donor imputation, often called nearest‐neighbour imputation. In this paper, the authors develop a variance estimator for donor imputation based on the assumption that the imputed estimator of a domain total is approximately unbiased under an imputation model; that is, a model for the variable requiring imputation. Their variance estimator is valid, irrespective of the magnitude of the sampling fractions and the complexity of the donor imputation method, provided that the imputation model mean and variance are accurately estimated. They evaluate its performance in a simulation study and show that nonparametric estimation of the model mean and variance via smoothing splines brings robustness with respect to imputation model misspecifications. They also apply their variance estimator to real survey data when nearest‐neighbour imputation has been used to fill in the missing values. The Canadian Journal of Statistics 37: 400–416; 2009 © 2009 Statistical Society of Canada     

Transnational political practices and the receiving state: Turks and Kurds in Germany and the Netherlands

This article examines how the social and political contexts in receiving countries affect the transnational political practices of migrants and refugees, such as their mobilization around political events in their homeland. The case study explores the political participation of Turks and Kurds in Germany and the Netherlands in its full complexity, that is in both the immigration country and in homeland politics. The findings suggest that transnational political practices should not be reduced to a function of the political opportunity structures of particular receiving countries for two main reasons: (a) more inclusive political structures, which provide for more participation and co‐operation on immigrant political issues, may at the same time, and for that very reason, serve to exclude dialogue on homeland politics; (b) homeland political movements may draw on a different range of resources than their immigrant political counterparts, including those outside the local political institutional context.     

Evaluating the Effectiveness of Risk-Reduction Strategies for Consumer Chemical Products

Communication about risks offers a voluntary approach to reducing exposure to pollutants. Its adequacy depends on its impact on behavior. Estimating those impacts first requires characterizing current activities and their associated risk levels, and then predicting the effectiveness of risk-reduction strategies. Characterizing the risks from chemical consumer products requires knowledge of both the physical and the behavioral processes that influence exposures. This article presents an integrated approach that combines consumer interviews, users' beliefs and behaviors, and quantitative exposure modeling. This model was demonstrated in the context of consumer exposure to a methylene chloride-based paint stripper, showing how it could be used to evaluate current levels of risk and predict the effectiveness of proposed voluntary risk-reduction strategies.     

A Risk Assessment Method for Biological Introductions

This article describes an application of a method for assessing risks associated with the introduction of an organism into a new environment. The test organism was a binucleate Rhizoctonia fungal isolate that has potential for commercial development as a biological control agent for damping-off diseases in bedding plants. A test sample of host plant species was selected using the centrifugal phylogenetic host range principles, but with an emphasis on economic species. The effect of the fungus on the plant was measured for each species and expressed on a logarithmic scale. The effects on weights of shoots and roots per container were not normally distributed, nor were the effects on the number of plants standing (those which survived). Statements about the effect on the number standing and the shoot weight per container involved using the observed (empirical) distribution. This is illustrated with an example. Problems were encountered in defining the population of species at risk, and in deciding how this population should be formally sampled. The limitations of the method are discussed.     

Citizens' attitudes towards economic insecurity and government after the 2007 financial tsunami: A Hong Kong and Taiwan comparison

Wang KY‐T, Wong C‐k, Tang K‐L. Citizens' attitudes towards economic insecurity and government after the 2007 financial tsunami: A Hong Kong and Taiwan comparison The purpose of this study was to investigate people's attitudes to economic insecurity and government in Hong Kong and Taiwan after the financial tsunami of 2007. Random sampling telephone surveys were conducted in July 2009. These are the main conclusions: First, the most vulnerable groups hurt by the financial crisis were low‐income families and people who had lost their job or were afraid of losing it. This implies that the old policy issue of social stratification and the emerging policy issue of employment insecurity coexisted during the financial crisis. Second, personal experiences of economic insecurity had an influence on people's perceptions of the severity of the economic crisis at the societal level. Third, citizens had ambivalent feelings about public interventions during the crisis. Fourth, there were both convergence and divergence between Hong Kong and Taiwan with regard to attitudes to particular issues. The policy implications of these findings are discussed in the final section of this article.     

Decision Making Clusters in Retirement Savings: Gender Differences Dominate

This study explored the impact of demographic factors on individuals’ investment choice decisions in retirement savings funds. Analysis found identifiable member clusters across a large and diverse sample of almost 150,000 transactions. Results suggested that gender and risk are the most dominant factors with women showing a strong tendency to make lower risk investment choices. If this behavioural tendency is not addressed through education it will accentuate the hurdles women already face in accumulating adequate saving for retirement.     

INTERPERSONAL CONTEXT AT WORK AND THE FREQUENCY,APPRAISAL, AND CONSEQUENCES OF BOUNDARY‐SPANNING DEMANDS

Compared to job‐specific conditions, the interpersonal context of work has received less attention from work–family scholars. Using data from a 2007 U.S. survey of workers (N = 1,286), we examine the impact of workplace social support and interpersonal conflict on work–family conflict and exposure to boundary‐spanning demands—as indexed by the frequency that workers receive work‐related contact outside of normal work hours. Findings indicate that workplace social support is associated negatively with work‐to‐family conflict, while interpersonal conflict at work is associated with higher levels of work‐to‐family conflict. Results also indicate that both supportive and conflictive work contexts are associated with more frequent exposure to boundary‐spanning demands. However, workers in supportive contexts are more likely to appraise these demands as beneficial for accomplishing work tasks, and are less likely to appraise them as disruptive to family roles. By contrast, workers in conflictive contexts are more likely to appraise demands as disruptive to family roles, and are less likely to appraise them as beneficial for paid work. Consequently, our findings underscore the resource and demands aspects of interpersonal work contexts and their implications for the work–family interface.     

Robustness of Risk Maps and Survey Networks to Knowledge Gaps About a New Invasive Pest

In pest risk assessment it is frequently necessary to make management decisions regarding emerging threats under severe uncertainty. Although risk maps provide useful decision support for invasive alien species, they rarely address knowledge gaps associated with the underlying risk model or how they may change the risk estimates. Failure to recognize uncertainty leads to risk‐ignorant decisions and miscalculation of expected impacts as well as the costs required to minimize these impacts. Here we use the information gap concept to evaluate the robustness of risk maps to uncertainties in key assumptions about an invading organism. We generate risk maps with a spatial model of invasion that simulates potential entries of an invasive pest via international marine shipments, their spread through a landscape, and establishment on a susceptible host. In particular, we focus on the question of how much uncertainty in risk model assumptions can be tolerated before the risk map loses its value. We outline this approach with an example of a forest pest recently detected in North America, Sirex noctilio Fabricius. The results provide a spatial representation of the robustness of predictions of S. noctilio invasion risk to uncertainty and show major geographic hotspots where the consideration of uncertainty in model parameters may change management decisions about a new invasive pest. We then illustrate how the dependency between the extent of uncertainties and the degree of robustness of a risk map can be used to select a surveillance network design that is most robust to knowledge gaps about the pest.     

Linking Local Government Discretion and Accountability in Decentralisation

Decentralisation offers significant opportunities to improve government accountability by exerting stronger pressures both from below (demand) and above (supply). The literature contains many examples, however, where the potential has not been realised, partly because decentralisation reforms have often been introduced without thinking through their accountability implications. Even when accountability is taken into account, the efforts tend to emphasise either the supply or the demand side of the equation, but not both. Drawing on the sets of literature on fiscal, administrative and political decentralisation, this article presents a methodology for studying this.