Nonparametric estimation of the link function including variable selection

Nonparametric methods for the estimation of the link function in generalized linear models are able to avoid bias in the regression parameters. But for the estimation of the link typically the full model, which includes all predictors, has been used. When the number of predictors is large these methods fail since the full model cannot be estimated. In the present article a boosting type method is proposed that simultaneously selects predictors and estimates the link function. The method performs quite well in simulations and real data examples.     

The link between economic and social upgrading in global supply chains: Experiences from the Southern Cone

This article uses nine case studies of global supply chains (GSCs) in Southern Cone countries to explore the extent to which economic and social upgrading are linked and spread from lead firms to their supply chain. While economic and social upgrading are found in lead firm segments throughout the case studies, the impacts on suppliers are varied. Pattern groupings enable the authors to develop a three‐part typology of development in GSCs, in the light of which they consider the roles of public policies, company behaviour and social actors in addressing developmental outcomes for GSC lead firms and suppliers.     

Paradoxe Folgen finanzieller Anreize zur Arbeitsaufnahme für die Beschäftigungsstabilität

Financial incentives to work (in-work benefits) are an instrument of labour market policy to motivate the unemployed to re-enter employment. Following neoclassical economic reasoning, such financial incentives should be effective, since the unemployed are expected to maximize financial utility. However, one common empirical finding is that such wage-subsidized employment is rather unstable. Applying Boudons cognitivist model to the ending of wage-subsidized employment the hypotheses are derived that firstly the in-work benefit is interpreted by the employee as a signal for the firm’s violation of the norm of reciprocity and secondly that the employee’s resulting sanctioning behaviour can raise the probability for job terminations. Survey data on in-work benefit recipients is used to test the hypotheses, performing ordered logit and event history analysis in combination with propensity score matching. Results from the empirical analysis support the hypotheses. It is concluded that labour market policy should be based not only on the assumption of economically rational behaviour, if labour market programmes are to be effective.     

Casino Self- and Forced Excluders’ Gambling Behavior Before and After Exclusion

Casino exclusion programs are intended to prevent or limit gambling-related harm. Although previous research showed that self-exclusion is associated with reduced gambling, it remains unknown whether self- and forced excluded subjects show different patterns of gambling behavior and if exclusion from casino gambling affects all gambling activities. The present study retrospectively investigated (1) the role of voluntariness of exclusion for the first time, and (2) general gambling behavior of excluded individuals before and after exclusion. A total of N = 215 casino excluders (self-excluders: n = 187, forced excluders: n = 28) completed an online survey or a face-to-face interview up to 8 years after enrollment. Self- and forced excluders showed similar rates of abstinence (self-excluders: 19.3%, forced excluders: 28.6%) and reduction (self-excluders: 67.4%, forced excluders: 60.7%), even though forced excluders reported a significantly greater initial gambling intensity compared to self-excluders (e.g., pre-exclusion gambling time; self-excluders: 3.2 days/week, forced excluders: 4.3 days/week). Overall, results indicated that 20.5% of excluders stopped all gambling activities and another 66.5% reduced their gambling. Those who continued gambling significantly reduced this behavior in every segment, except for gambling halls. Findings indicate that self- and forced exclusion are associated with similarly reduced gambling behavior, even in non-excluded segments. However, unchanged gambling in gambling halls emphasizes the importance to implement consistent exclusion programs over all gambling segments.     

Penalized regression with correlation-based penalty

A new regularization method for regression models is proposed. The criterion to be minimized contains a penalty term which explicitly links strength of penalization to the correlation between predictors. Like the elastic net, the method encourages a grouping effect where strongly correlated predictors tend to be in or out of the model together. A boosted version of the penalized estimator, which is based on a new boosting method, allows to select variables. Real world data and simulations show that the method compares well to competing regularization techniques. In settings where the number of predictors is smaller than the number of observations it frequently performs better than competitors, in high dimensional settings prediction measures favor the elastic net while accuracy of estimation and stability of variable selection favors the newly proposed method.     

Has the HIV Epidemic Peaked?

This study reviews the highly diverse regional and country patterns of HIV epidemics and discusses possible causes of the geographic variation in epidemic sizes. Past trends and projections of the epidemics are presented and the peak years of epidemics are estimated. The potential future impact of new prevention technologies is briefly assessed. A final section summarizes the future impact of the epidemic on key demographic variables. The main finding of this analysis is that the HIV epidemic reached a major turning point over the past decade. The peak years of HIV incidence rates are past for all regions, and the peaks of prevalence rates are mostly in the past except in Eastern Europe, where they are expected to peak in 2008. But owing in part to the life‐prolonging effect of antiretroviral therapy and to sustained population growth, the absolute number of infected individuals is expected to keep growing slowly in sub‐Saharan Africa and to remain near current levels worldwide, thus posing a continuing challenge to public health programs. No country is expected to see a decline in its population size between 2005 and 2050 that is attributable to high mortality related to AIDS.     

Supplier‐Switching Inertia and Competitive Asymmetry: A Demand‐Side Perspective*

Building on strategic management, operations strategy, and supplier management literatures, this article presents a framework for supplier selection from the demand‐side perspective. We highlight the role of a purchasing firm's switching inertia in the supplier‐selection process and demonstrate the usefulness of our framework for the industrial automation industry. Empirical data for this study was collected from 171 corporate and plant‐level executives in pharmaceutical, chemical, and paper‐and‐pulp manufacturing industries in the United States. A series of Web‐based individually customized discrete choice experiments asked the respondents to either switch to the new supplier or stay with the existing supplier. Based on the results of these experiments, we demonstrate the existence of switching inertia in the supplier‐selection process and discuss the managerial implications for incumbent and challenger supplier firms.     

Beliefs About and Attitudes Toward Gambling in French-Speaking Switzerland

The present study aims to analyze attitudes and beliefs of the French-speaking general Swiss population (n = 2500; female n = 1280; mean age = 43 years) as regards gambling, which are to date almost exclusively studied in the North American and Australian contexts. Beliefs related to gambling include the perception of the effectiveness of preventive measures toward gambling, the comparative risk assessment of different addictive behaviors, the perceived risks of different types of gambling and attitudes are related to the gambler’s personality. The general population perceived gambling rather negatively and was conscious of the potential risks of gambling; indeed, 59.0% of the sample identified gambling as an addictive practice. Slot machines were estimated to bear the highest risk. Compared with women and older people, men and young people indicated more positive beliefs about gambling; they perceived gambling as less addictive, supported structural preventive measures less often, and perceived gambling as a less serious problem for society. Gamblers were more likely to put their practices into perspective, perceiving gambling more positively than non-gamblers. General population surveys on such beliefs can deliver insights into preventive actions that should be targeted to young men who showed more favorable views of gambling, which have been shown to be associated with increased risk for problematic gambling.