Choice of the ridge factor from the correlation matrix determinant

Ridge regression is the alternative method to ordinary least squares, which is mostly applied when a multiple linear regression model presents a worrying degree of collinearity. A relevant topic in ridge regression is the selection of the ridge parameter, and different proposals have been presented in the scientific literature. Since the ridge estimator is biased, its estimation is normally based on the calculation of the mean square error (MSE) without considering (to the best of our knowledge) whether the proposed value for the ridge parameter really mitigates the collinearity. With this goal and different simulations, this paper proposes to estimate the ridge parameter from the determinant of the matrix of correlation of the data, which verifies that the variance inflation factor (VIF) is lower than the traditionally established threshold. The possible relation between the VIF and the determinant of the matrix of correlation is also analysed. Finally, the contribution is illustrated with three real examples.     

Not just a number? NEETs,data and datalogical systems

This paper draws on empirical research with NEET populations (16–24-year-olds not in education, employment or training) in the U.K. in order to engage with issues around identification, data and metrics produced through datalogical systems. Our aim is to bridge contemporary discourses around data, digital bureaucracy and datalogical systems with empirical material drawn from a long-term ethnographic project with NEET groups in Leeds, U.K. in order to highlight the way datalogical systems ideologically and politically shape people’s lives. We argue that NEET is a long-standing data category that does work and has resonance within wider datalogical systems. Secondly, that these systems are decision-making and far from benign. They have real impact on people’s lives – not just in a straightforwardly, but in obscure, complex and uneven ways which makes the potential for disruption or intervention increasingly problematic. Finally, these datalogical systems also implicate and are generated by us, even as we seek to critique them.     

Nonparametric estimator for mean residual life and vitality function

In this paper, we study the estimation of the vitality function(v(x)=E(X|X>x) and mean residual life function(e(x)=E(X-x|X>x) from a sample ofX using the empirical estimator and kernel estimator. Under suitable conditions of regularity, the asymptotic normality of the kernel estimator is obtained. Partially supported by Consejeria de Cultura y Ed. (C.A.R.M.), under Grant PIB 95/90.     

Between ‘Pioneers’ of the Cardiovascular Revolution and Its ‘Late Followers’: Mortality Changes in the Czech Republic and Poland Since 1968

After several decades of stagnation, mortality in most Central European countries started to decrease after 1989. The Czech Republic and Poland were the first former Communist countries in this region to experience a rapid and sustained increase in life expectancy. This study focuses on the trends in cause-of-death mortality that have contributed to the recent progress in these two countries. The analysis is based on the cause-of-death time series (1968–2013) reconstructed in accordance with the 10th ICD revision, which makes the data fully comparable over the full period under study. Actual trends in cause-specific mortality are presented, and age, sex and causes of death components of life expectancy changes are disentangled. In both countries, the reduction in cardiovascular mortality at adult and old ages was crucial for the increase in life expectancy after 1991. Results are discussed in the context of institutional changes that occurred after the fall of Communism, such as the reorientation of health policies and the emergence of non-governmental organizations. Changes in health-related attitudes and behaviours as well as structural changes in societies, notably the rising share of persons with tertiary education, are also discussed.     

Prohibition,Regulation or Free Market: A Mapping of Colombian People’s Perspectives Regarding National Drug Policies

Colombian laypersons’ perspectives regarding actual and potential drug policies were examined. Adults (N = 395) aged 18–68 and living in Bogota were presented with 24 vignettes that were composed according to two within-subject orthogonal factor designs: (a) Demand for drugs in the country × Current government policy regarding soft and hard drugs (from “laissez faire” policy for all drugs to complete prohibition of all drugs) and (b) Information campaigns regarding the dangerousness of drugs × Current policy. Participants rated the level of acceptability of each policy. Seven different perspectives were identified that can be grouped into five broad views. The first one (50 % of participants) was called “radical constructionists” because participants considered that all policies were unacceptable. The second one (19 %) was called “cultural conservatives” because only one drug policy was considered fully acceptable: complete prohibition (although half of the members of this group were willing to allow soft drugs to be sold freely). The third one (14 %) was called “progressive prohibitionists” because the preferred policies in this group were either complete prohibition or complete regulation by the government. The fourth one (8 %) was called “free trade libertarians” because the dominant opinion was that the drug market should be free. The last one (5 %) was called “progressive advocates of legalization” because the preferred policy in this group was complete regulation of all substances. In most cases, the presence of information campaigns was highly valued. Methodological implications and implications for decision-makers are discussed.     

Your work may be killing you! Workaholism,sleep problems and cardiovascular risk

This study tests the relationships between workaholism (i.e. working excessively and compulsively), sleep problems and cardiovascular risk in 537 employees from five Spanish hospitals. Four types of worker (i.e. workaholics, positive workers, compulsive workers and hard workers) were distinguished, and their health indicators were compared. The results showed that workaholics experienced significantly more sleep problems (i.e. morning tiredness, sleeping while driving and sleeping fewer hours both on weekdays and at weekends, with poorer quality), had higher relative risk scores, and consumed more caffeine and alcohol than the other patterns of worker (positive, compulsive and hard workers). Further analyses revealed that sleep problems fully mediated the relationship between workaholism (i.e. working excessively and compulsively) and cardiovascular risk. The study emphasizes the fact that being a workaholic might be a significant risk factor for having sleep problems and cardiovascular disease.     

International Business and National Culture: A Literature Review and Research Agenda

This literature review analyzes leading international business and management journals from 2000 to 2012 in order to explore the role of national culture in international business research. Through the analysis of the 265 selected articles, the study thematically maps the field and identifies research challenges and opportunities. It reflects on avenues for future research related to both thematic and methodological issues, among them: research focused on the impact of the home/host national culture on internationalization processes (as existing literature mainly focuses on cultural distance); the role to be played by new theoretical frameworks; and the need to consider cultural positions and cultural friction rather than traditional cultural distance when analyzing internationalization decisions.     

Intergenerational Activities that Promote Engaging Conversations are Preferred among Young and Older Adults

ABSTRACT

Loneliness negatively affects young and older adults. Intergenerational activities foster social connectedness. Using quantitative and qualitative methods, this study explored which intergenerational activities are most enjoyable for college students and retirement community residents. Demographics, loneliness, enjoyment, conversation level, and type of activity were analyzed. The enjoyment and conversation variables were positively correlated (r = .59, p < .001) which was supported by participants’ narratives. Both populations most enjoyed the activities with higher conversation levels, with the first being committees, followed by meals, one on one activities, and transportation. Retirement communities and universities should promote intergenerational activities, which include meaningful conversations.     

Unemployment and Earnings Assimilation of Immigrants

The regional unemployment elasticity of annual earnings for non‐OECD immigrants is found to be more than three times larger than for natives, using micro data covering all immigrants in Norway in 1990 and a random sample of natives. The decline in relative earnings of non‐OECD immigrants from 1980 to 1990 can largely be explained by the stronger impact of rising unemployment on immigrant earnings. These results highlight the importance of controlling for different period effects caused by fluctuating unemployment in panel studies of earnings assimilation among immigrants.