Comparing Estimates of the Effects of Air Pollution on Human Mortality Obtained Using Different Regression Methodologies

Studies using regression techniques report their results using a variety of statistics. Evaluation of the consistency of findings, such as in a metaanalysis, requires calculating the statistical estimates of the effect reported in each study in a comparable manner. In this paper, we consider multiple linear regression, multiple Poisson regression, and logistic regression estimates. We present results that are needed to calculate, on a common basis, the slope of the regression function at a specified value, the elasticity function of the regression function at a specified value, the relative risk at a specified value, and the odds ratio at a specified value. We apply these results to studies of the association of daily mortality in an area to the daily air pollution level of ozone and PM₁₀. We calculate the estimated slope of the number of deaths per billion population associated with an increase of 1 ppb of ozone level in studies of daily mortality in three urban areas. These studies, in Los Angeles, New York, and St. Louis, produced very comparable results on a common basis, especially when compared to the coefficients as reported. We also calculated the estimated elasticity function of the daily mortality and daily PM₁₀ level for eight areas and found that the elasticities varied within a factor of roughly two, much less than the variability in the coefficients as reported.     

Mixing patterns between age groups in social networks

We present a method for estimating transmission matrices that describe the mixing and the probability of infection between age groups. Transmission matrices can be used to estimate age-dependent forces of infection in age-structured, compartmental models for the study of infectious diseases. We analyze the social network generated by the synthetic population of Portland and extract mixing patterns. Our results show that the mixing within the population consists of two groups, children and adults. Children interact most frequently with other children close to their own age, while adults interact with a wider range of age groups and the durations of typical adult contacts are shorter than typical contacts between children. Furthermore, the transmission matrix shows that children are more likely to acquire infection than adults.     

Development and Consideration of Global Policies for Managing the Future Risks of Poliovirus Outbreaks: Insights and Lessons Learned Through Modeling

The success of the Global Polio Eradication Initiative promises to bring large benefits, including sustained improvements in quality of life (i.e., cases of paralytic disease and deaths avoided) and costs saved from cessation of vaccination. Obtaining and maintaining these benefits requires that policymakers manage the transition from the current massive use of oral poliovirus vaccine (OPV) to a world without OPV and free of the risks of potential future reintroductions of live polioviruses. This article describes the analytical journey that began in 2001 with a retrospective case study on polio risk management and led to development of dynamic integrated risk, economic, and decision analysis tools to inform global policies for managing the risks of polio. This analytical journey has provided several key insights and lessons learned that will be useful to future analysts involved in similar complex decision-making processes.     

Mental load and work stress as two types of energy mobilization

A conceptual framework is presented in which mental load and stress are regarded as two distinct biobehavioural states in the work environment that differ in energy mobilization, mood and coping strategy. The framework combines two types of theory that are based on human performance research using laboratory tasks on the one hand and applied research in the work environment on the other. A high workload is regarded as an important but not a critical factor in the development of stress symptoms. Even under unfavourable conditions it is possible to work intensively and to be highly activated without feelings of strain or psychosomatic complaints. In contrast, working conditions that provide few possibilities for control and little social support or are associated with reduced well-being and increased health risks. The two states differ in activation, coping style and mood. A proper distinction is important not only for theory building but also for the reconstruction of the work environment. It may lead to recommendations that aim to enhance the work efficiency of employees while reducing the probability that stress responses will occur.     

Environmental assessment in forestry: the initial experience

This study analyses the effectiveness of the European Community's Environmental Assessment Directive of 1985 in its application in the U.K. forestry sector. It assesses the applicability of the regulations in the provision of the public and private outputs of forestry. The environmental assessment regulation may contribute to the provision of the optimal amount of these public and private goods in theory, but it is concluded that, in common with initial results of the environmental assessment process in other sectors, the regulations do not make this contribution in practice in the forestry sector. The main deficiencies of the environmental statements examined were the failure to identify the significant potential impacts; to present alternative project sites and design features; and the erroneous measure of particular externalities. The environmental assessment process was also found to be unsatisfactory in the lack of public accessibility and consultation. The need for revision of the process in the forestry sector is highlighted.     

Best monotone M‐estimators

The author shows how to find M‐estimators of location whose generating function is monotone and which are optimal or close to optimal. It is easy to identify a consistent sequence of estimators in this class. In addition, it contains simple and efficient approximations in cases where the likelihood function is difficult to obtain. In some neighbourhoods of the normal distribution, the loss of efficiency due to the approximation is quite small. Optimal monotone M‐estimators can also be determined in cases when the underlying distribution is known only up to a certain neighbourhood. The author considers the e‐contamination model and an extension thereof that allows the distributions to be arbitrary outside compact intervals. His results also have implications for distributions with monotone score functions. The author illustrates his methodology using Student and stable distributions.     

VOTING AND IMITATIVE BEHAVIOR

Political behavior generates private benefits by helping people fit in with desired friends. A voter imitates other voters, but at the same time they imitate him. An equilibrium solution requires exogenous variables: the narrow self-interest of the participants. The reduced form makes one's vote a function of the narrow self-interest of others as well as one's own. In accord with the model, a person's party identification depends on his ethnic group's current income and its income in 1909 as well as his own income.     

NONPARAMETRIC QUANTILE ESTIMATION FROM RECORD-BREAKING DATA

Sometimes, in industrial quality control experiments and destructive stress testing, only values smaller than all previous ones are observed. Here we consider nonparametric quantile estimation, both the ‘sample quantile function’ and kernel-type estimators, from such record-breaking data. For a single record-breaking sample, consistent estimation is not possible except in the extreme tails of the distribution. Hence replication is required, and for m. such independent record-breaking samples the quantile estimators are shown to be strongly consistent and asymptotically normal as m-→∞. Also, for small m, the mean-squared errors, biases and smoothing parameters (for the smoothed estimators) are investigated through computer simulations.