A Simulation Study of Some Biasing Parameters for the Ridge Type Estimation of Poisson Regression

This article proposes several estimators for estimating the ridge parameter k based on Poisson ridge regression (RR) model. These estimators have been evaluated by means of Monte Carlo simulations. As performance criteria, we have calculated the mean squared error (MSE), the mean value, and the standard deviation of k. The first criterion is commonly used, while the other two have never been used when analyzing Poisson RR. However, these performance criteria are very informative because, if several estimators have an equal estimated MSE, then those with low average value and standard deviation of k should be preferred. Based on the simulated results, we may recommend some biasing parameters that may be useful for the practitioners in the field of health, social, and physical sciences.     

Beyond tail median and conditional tail expectation: Extreme risk estimation using tail Lp-optimization

The conditional tail expectation (CTE) is an indicator of tail behavior that takes into account both the frequency and magnitude of a tail event. However, the asymptotic normality of its empirical estimator requires that the underlying distribution possess a finite variance; this can be a strong restriction in actuarial and financial applications. A valuable alternative is the median shortfall (MS), although it only gives information about the frequency of a tail event. We construct a class of tail L^p-medians encompassing the MS and CTE. For p in (1,2), a tail L^p-median depends on both the frequency and magnitude of tail events, and its empirical estimator is, within the range of the data, asymptotically normal under a condition weaker than a finite variance. We extrapolate this estimator and another technique to extreme levels using the heavy-tailed framework. The estimators are showcased on a simulation study and on real fire insurance data.     

Creating a reference to a complex emergency situation using time series methods: war in Guinea-Bissau 1998-1999

Impacts of complex emergencies or relief interventions have often been evaluated by absolute mortality compared to international standardized mortality rates. A better evaluation would be to compare with local baseline mortality of the affected populations. A projection of population-based survival data into time of emergency or intervention based on information from before the emergency may create a local baseline reference. We find a log-transformed Gaussian time series model where standard errors of the estimated rates are included in the variance to have the best forecasting capacity. However, if time-at-risk during the forecasted period is known then forecasting might be done using a Poisson time series model with overdispersion. Whatever, the standard error of the estimated rates must be included in the variance of the model either in an additive form in a Gaussian model or in a multiplicative form by overdispersion in a Poisson model. Data on which the forecasting is based must be modelled carefully concerning not only calendar-time trends but also periods with excessive frequency of events (epidemics) and seasonal variations to eliminate residual autocorrelation and to make a proper reference for comparison, reflecting changes over time during the emergency. Hence, when modelled properly it is possible to predict a reference to an emergency-affected population based on local conditions. We predicted childhood mortality during the war in Guinea-Bissau 1998-1999. We found an increased mortality in the first half-year of the war and a mortality corresponding to the expected one in the last half-year of the war.     

Uncertain Numbers and Uncertainty in the Selection of Input Distributions—Consequences for a Probabilistic Risk Assessment of Contaminated Land

Risks from exposure to contaminated land are often assessed with the aid of mathematical models. The current probabilistic approach is a considerable improvement on previous deterministic risk assessment practices, in that it attempts to characterize uncertainty and variability. However, some inputs continue to be assigned as precise numbers, while others are characterized as precise probability distributions. Such precision is hard to justify, and we show in this article how rounding errors and distribution assumptions can affect an exposure assessment. The outcome of traditional deterministic point estimates and Monte Carlo simulations were compared to probability bounds analyses. Assigning all scalars as imprecise numbers (intervals prescribed by significant digits) added uncertainty to the deterministic point estimate of about one order of magnitude. Similarly, representing probability distributions as probability boxes added several orders of magnitude to the uncertainty of the probabilistic estimate. This indicates that the size of the uncertainty in such assessments is actually much greater than currently reported. The article suggests that full disclosure of the uncertainty may facilitate decision making in opening up a negotiation window. In the risk analysis process, it is also an ethical obligation to clarify the boundary between the scientific and social domains.     

Trust and health in Eastern Europe: Conceptions of a new society

Little attention has been paid to why trends and levels of mortality and morbidity differ in Eastern Europe and few studies have addressed people's own perceptions of their new political system – perceptions which per se may be important for social development. The aim of the present study was to analyse the extent to which trust and economic circumstances affect self‐rated health in Poland, Estonia and Russia and how much health differences between the countries can be explained by these factors. A better economy and higher trust were related to better individual health, while economic factors seemed most important for inter‐country differences. It is probable that both institutional factors and individual perceptions contribute to people's well‐being, but in terms of social policy, an improved welfare system may be the most effective way forward.     

Relationship Quality in Marital and Cohabiting Unions Across Europe

In this study, the authors used data from the first wave of the Generations and Gender Survey to investigate relationship quality among currently married and cohabiting individuals ages 18 to 55 (N = 41,760) in 8 European countries (Bulgaria, France, Germany, Hungary, Norway, Romania, Russia, and The Netherlands). They expected to find fewer differences between cohabitation and marriage in countries where cohabitation is widespread. Controlling for a range of selection characteristics of respondents and their partners (e.g., common children, union duration, and education), the analyses showed that in all countries cohabiters more often had breakup plans and were less satisfied with their relationships than individuals who married. This cohabitation gap in relationship quality was largest in Russia, Romania, and Germany, which indeed were among the countries in the current sample where cohabitation was least prevalent.     

Symptoms of Eating Disorders Among Females in Drug Addiction Treatment

The aim of this study is to measure and describe symptoms of eating disorders among females in treatment for drug addiction in Norway. Previous clinical and epidemiological studies have revealed coprevalence between eating disorders and substance use or abuse. However, few studies have measured eating disorders in drug-using samples and even fewer within the context of drug treatment. In this study, 29 females with drug use disorder in residential treatment were tested with the Eating Disorder Inventory–2. A subgroup of 9 females (31%) with significant symptoms of eating disorders was identified. The characteristics of this group and possible clinical consequences are discussed.     

Toddlers Help Anonymously

Young children are extremely motivated to help others, but it is not clear whether they do so in anonymous situations without social recognition. In two studies, we found that 18‐month‐old toddlers provided help equally in situations where an adult recipient was present and in situations where an adult recipient was not present. We included several control conditions to rule out that toddlers were simply unaware of their anonymity or were merely motivated to restore the physical order of things. Together, these findings suggest that early in ontogeny children are motivated to help others in need regardless of whether they can immediately be recognized for their prosocial intentions.     

Forms of gambling,gambling involvement and problem gambling: evidence from a Swedish population survey

The purpose of this study was to explore the association between problem gambling (PG) and participation in different forms of gambling in order to elucidate relationships between PG, gambling involvement and gambling intensity. Using data from the first wave of the Swedish Longitudinal Gambling Study (Swelogs) (n = 4,991), the study tested four hypotheses, namely that (1) some forms of gambling are more closely associated with PG than other forms; (2) high gambling involvement is associated with PG; (3) gambling involvement is positively associated with the intensity of gambling; and (4) the relationship between gambling involvement and PG is influenced by the specific forms of gambling in which individuals participate. All four hypotheses were supported. More specifically, the study found that while many PGs regularly participate in multiple forms of gambling, half of PGs participate regularly in only one or two forms of gambling. The study concluded that some forms of gambling are more closely associated with problem gambling than other forms, and that gambling policy and regulation, as well as the development of responsible gambling initiatives, should focus on these forms.