Eliciting Risk and Time Preferences

We design experiments to jointly elicit risk and time preferences for the adult Danish population. Since subjects are generally risk averse, we find that joint elicitation provides estimates of discount rates that are significantly lower than those found in previous studies and more in line with what would be considered as a priori reasonable rates. The statistical specification relies on a theoretical framework that involves a latent trade‐off between long‐run optimization and short‐run temptation. Estimation of this specification is undertaken using structural, maximum likelihood methods. Our main results based on exponential discounting are robust to alternative specifications such as hyperbolic discounting. These results have direct implications for attempts to elicit time preferences, as well as debates over the appropriate domain of the utility function when characterizing risk aversion and time consistency.     

Bimodality based on the generalized skew-normal distribution

This paper focuses on the development of a new extension of the generalized skew-normal distribution introduced in Gómez et al. [Generalized skew-normal models: properties and inference. Statistics. 2006;40(6):495–505]. To produce the generalization a new parameter is introduced, the signal of which has the flexibility of yielding unimodal as well as bimodal distributions. We study its properties, derive a stochastic representation and state some expressions that facilitate moments derivation. Maximum likelihood is implemented via the EM algorithm which is based on the stochastic representation derived. We show that the Fisher information matrix is singular and discuss ways of getting round this problem. An illustration using real data reveals that the model can capture well special data features such as bimodality and asymmetry.     

On the mixtures of Weibull and Pareto (IV) distribution: An alternative to Pareto distribution

Finite mixture models have provided a reasonable tool to model various types of observed phenomena, specially those which are random in nature. In this article, a finite mixture of Weibull and Pareto (IV) distribution is considered and studied. Some structural properties of the resulting model are discussed including estimation of the model parameters via expectation maximization (EM) algorithm. A real-life data application exhibits the fact that in certain situations, this mixture model might be a better alternative than the rival popular models.     

Risk attitudes in a social context

Many experiments have demonstrated that when evaluating payoffs, people take not only their own payoffs into account, but also the payoffs of others in their social environment. Most of this evidence is found in settings where payoffs are riskless. It is plausible that if people care about the payoffs of others, they do so not only in a riskless context, but also in a risky one. This suggests that an individual’s decision making under risk depends on the risks others in his or her environment face. This paper is the first to test whether individuals’ risk attitudes are affected by the risks others face. The results show that risk attitudes appear to be less affected by others’ risks than expected, even though the same subjects do show concerns for inequality in a riskless setting. Interestingly, we find that people prefer risks to be independent across individuals in society rather than correlated.     

‘Drink a 12 box before you go’: pre-loading among young people in Aotearoa New Zealand

The practice of pre-loading—drinking large amounts of alcohol rapidly in private spaces prior to socialising in the night-time economy—has come to notice recently in the study of alcohol-related harm, but no studies have explored these phenomena in Aotearoa New Zealand. We used a theoretical framework developed with public health alcohol studies for understanding drinking cultures that conceptualises patterns of behaviours as arising within a dynamic interaction between forces of hedonism, function and control. We report findings from 34 focus groups conducted with 18–25 year olds as part of a project supported by the Marsden Fund, between 2011 and 2012, to investigate drinking cultures among young people. Our thematic analyses of participants’ accounts of pre-loading show that the term is in common use, applying to a range of practices motivated by price of alcohol but influenced by the pleasures of intoxication, the importance of peer processes and certain aspects of the regulatory system. We conclude with a discussion of the usefulness of the framework and the implications of the findings for public health policy that aims to reduce alcohol consumption and the harm that arises from it.     

Spectral estimation for locally stationary time series with missing observations

Time series arising in practice often have an inherently irregular sampling structure or missing values, that can arise for example due to a faulty measuring device or complex time-dependent nature. Spectral decomposition of time series is a traditionally useful tool for data variability analysis. However, existing methods for spectral estimation often assume a regularly-sampled time series, or require modifications to cope with irregular or ‘gappy’ data. Additionally, many techniques also assume that the time series are stationary, which in the majority of cases is demonstrably not appropriate. This article addresses the topic of spectral estimation of a non-stationary time series sampled with missing data. The time series is modelled as a locally stationary wavelet process in the sense introduced by Nason et al. (J. R. Stat. Soc. B 62(2):271–292, 2000) and its realization is assumed to feature missing observations. Our work proposes an estimator (the periodogram) for the process wavelet spectrum, which copes with the missing data whilst relaxing the strong assumption of stationarity. At the centre of our construction are second generation wavelets built by means of the lifting scheme (Sweldens, Wavelet Applications in Signal and Image Processing III, Proc. SPIE, vol. 2569, pp. 68–79, 1995), designed to cope with irregular data. We investigate the theoretical properties of our proposed periodogram, and show that it can be smoothed to produce a bias-corrected spectral estimate by adopting a penalized least squares criterion. We demonstrate our method with real data and simulated examples.     

Time as a limited resource: Communication strategy in mobile phone networks

We used a large database of 9 billion calls from 20 million mobile users to examine the relationships between aggregated time spent on the phone, personal network size, tie strength and the way in which users distributed their limited time across their network (disparity). Compared to those with smaller networks, those with large networks did not devote proportionally more time to communication and had on average weaker ties (as measured by time spent communicating). Further, there were not substantially different levels of disparity between individuals, in that mobile users tend to distribute their time very unevenly across their network, with a large proportion of calls going to a small number of individuals. Together, these results suggest that there are time constraints which limit tie strength in large personal networks, and that even high levels of mobile communication do not fundamentally alter the disparity of time allocation across networks.     

Grandparenting across borders: American grandparents and their Israeli grandchildren in a transnational reality

Families are increasingly dispersed across national borders. Americans in Israel are one migrant group that represents the worldwide phenomenon of transnationalism. Grandparents separated geographically from their grandchildren develop new means of communication with them and new kinds of relationships. This study uses ethnographic interviews with the grandparents of transnational, American-Israeli children and youth to offer an in-depth examination of the experience of grandparenting across borders. We find that grandparenting children who are both geographically distant and raised in a foreign culture necessitates the development of new ways of maintaining relationships with grandchildren. This study considers the impact of transnational migration on the extended family, on those left behind, who struggle with redefining their roles as grandparents and with the sense of being deprived of the roles they had expected to play.     

The Institute of Philosophy Is the Country's Central Philosophical Establishment

The author recollects the significant landmarks in the institute's development, which coincides with and reflects the history of the country over the past eighty years.     

The Post-Soviet Party of Power

The author analyzes the character, role, structure, functions, and evolution of United Russia as a "party of power" in the context of world experience with dominant and predominant parties in competitive political systems.