Learning the two parameters of the Poisson–Dirichlet distribution with a forensic application

In forensic science, the rare type match problem arises when the matching characteristic from the suspect and the crime scene is not in the reference database; hence, it is difficult to evaluate the likelihood ratio that compares the defense and prosecution hypotheses. A recent solution consists of modeling the ordered population probabilities according to the two-parameter Poisson–Dirichlet distribution, which is a well-known Bayesian nonparametric prior, and plugging the maximum likelihood estimates of the parameters into the likelihood ratio. We demonstrate that this approximation produces a systematic bias that fully Bayesian inference avoids. Motivated by this forensic application, we consider the need to learn the posterior distribution of the parameters that governs the two-parameter Poisson–Dirichlet using two sampling methods: Markov Chain Monte Carlo and approximate Bayesian computation. These methods are evaluated in terms of accuracy and efficiency. Finally, we compare the likelihood ratio that is obtained by our proposal with the existing solution using a database of Y-chromosome haplotypes.     

Until work do us part: Labour migration and occupational stratification in non-cohabiting marriage

While recent decades have seen considerable research on cohabitation without marriage, the study of marriage without cohabitation has not fared as well. Prior work on the latter has emphasized the importance of occupational stratification, but ignored the social context around occupation, particularly regarding labour mobility and economic development. In this paper, we outline the significance of contemporary labour mobility and concomitant occupational stratification for the risk of non-cohabiting marriage, and use data from the IPUMS–International project to provide a cross-national accounting of non-cohabiting marriage. We focus on two issues: first, how does prevalence vary across countries, across time, and with respect to economic development? Second, how do the core dynamics of labour mobility—including migration, occupational status, and economic development—influence the probability of non-cohabiting marriage? Results indicate broad cross-national differences in prevalence, increasing risk over time, and a pattern of accumulating risk associated with multifaceted social disadvantage.     

Multilevel analysis in social research: An application of a cross-classified model

The multilevel approach can be a fruitful methodological framework in which to formulate the micro-macro relationships existing between individuals and their contexts. Usually, place of residence is taken as proxy for context. But individuals can be classified at the same level in more than one way. For example, not only may place of residence be relevant, but birthplace, household or working relations may also be taken into account. Contextual effects can be better identified if multiple classifications are simultaneously considered. in this sense, data do not have a purely hierarchical structure but a cross-classified one, and become very important to establish whether the resulting structure affects the covariance structure of data. In this paper, some critical issues arising from application of multilevel modelling are discussed, and multilevel cross-classified models are proposed as more flexible tools to study contextual effects. A multilevel cross-classified model is specified to evaluate simultaneously the effects of women's place of birth and women's current place of residence on the choice of bearing a second child by Italian women in the mid-1990s.     

Prognostic assessment of repeatedly measured time-dependent biomarkers,with application to dilated cardiomyopathy

We propose new time-dependent sensitivity, specificity, ROC curves and net reclassification indices that can take into account biomarkers or scores that are repeatedly measured at different time-points. Inference proceeds through inverse probability weighting and resampling. The newly proposed measures exploit the information contained in biomarkers measured at different visits, rather than using only the measurements at the first visits. The contribution is illustrated via simulations and an original application on patients affected by dilated cardiomiopathy. The aim is to evaluate if repeated binary measurements of right ventricular dysfunction bring additive prognostic information on mortality/urgent heart transplant. It is shown that taking into account the trajectory of the new biomarker improves risk classification, while the first measurement alone might not be sufficiently informative. The methods are implemented in an R package (longROC), freely available on CRAN.     

Child Health-Related Quality of Life and Parental Social Capital in Greece: An Exploratory Study

In this paper, we examined dimensions of child health-related quality of life in Greece in relation to parental assessments of neighbourhood social capital and social support networks. For the analysis, two main measures were used: (1) child self-reported health-related quality of life in ten dimensions, as measured by the KIDSCREEN questionnaire; (2) subjective measures of parental neighbourhood social capital and social support. Parental assessments of neighbourhood social capital and social support were both independently and positively associated with child self-reported health-related quality of life. However, they were not associated with the same dimensions of child well being, nor were they associated with all dimensions of child well being. These results suggest that greater attention in future research needs to be paid to the differential associations between the various dimensions of social capital and child health-related quality of life, with clear focus implications for social and health policies.     

Could the EQ-5D be Used to Predict Mortality and Hospitalization Over a Long Term Period?

Although numerous studies have demonstrated that social support affects a range of life experiences, only a few have examined the moderators and mediators such as self-esteem. According to self-control theory, self-control represents one’s ability to override or change one’s inner responses, and to interrupt undesired behavioral tendencies and refrain from acting on them. A high level of self-control may help individuals to mediate or moderate negative affect and thus weaken any adverse effects, contributing to their subjective well-being (SWB) in the long run. The current study explored how this interaction may affect the subjective well-being of the Chinese elderly, for whom self-control and social support are especially important life management issues. The study examined whether self-control mediates and moderates the relationship between social support and SWB among the elderly Chinese population. The data were collected from 335 elderly Chinese people (162 females and 173 males) from ten cities in central China, who completed the Chinese Social Support Scale, Trait Self-control Scale, Life Satisfaction Scale and Positive and Negative Affect Scale. The results showed that self-control, social support and SWB were strongly and significantly related. Hierarchical regression analysis showed that self-control partially mediated the influence of social support on SWB. Moreover, self-control moderated the relationship between social support and positive affect, but not life satisfaction and negative affect. These findings imply that self-control is a critical indicator of SWB and can serve as a basis for differentiating between intervention strategies that promote SWB among the elderly by helping them manage positive and negative affect. Future studies should further examine the internal mechanisms by which self-control influences SWB.     

The Spreading of Cohabitation as a Diffusion Process: Evidence from Italy

Drawing on seminal work by Nazio and Blossfeld (Eur J Popul 19(1):47–82, 2003) and Di Giulio and Rosina (Demogr Res 16(14):441–468, 2007), this paper tests whether the recent spread of cohabitation in Italy has followed the typical pattern of diffusion of innovation processes. In doing so, we contribute to the debate on the determinants of the emergence of “new” family behaviour. Following previous literature, innovative behaviour should spread initially through direct social modelling, i.e. interpersonal communication among highly selected individuals (peer effects). At later stages, the diffusion should spread through knowledge awareness of the innovation, i.e. communication with previous generations (pre-cohort effects), so that also less selected individuals are prone to adopt the new behaviour. In the specific Italian context—a Catholic, “familistic” setting, with high normative pressure and importance of parental approval—we surmise the influence of previous generations to be dominant. We use data from the “Family and Social Subjects” survey carried out by Istat (2009) and apply Event History Analysis in the form of competing-risks exponential models to study Italian women’s transition to cohabitation as first partnership. Results suggest that the most important driver of the spreading of cohabitation in Italy is represented by the degree of its diffusion among older cohorts. However, we find a positive and significant interaction between women’s education and peer effects at the onset of the phenomenon, in line with the Second Demographic Transition (SDT) hypothesis. Cohabitation is also more likely if parents experienced separation/divorce and, more generally, if the environment of the family of origin can be described as “SDT-friendly”.     

Mind the Covid-19 crisis: An evidence-based implementation of Next Generation EU

This paper develops an evidence-based approach to the selection and prioritisation of Next Generation EU (NGEU) projects for timely implementation and impact of the Recovery Plan for Europe. The analysis of a large sample of projects, currently funded by the European Union (EU) with the same priorities and objectives of NGEU, suggests that a timely implementation should be driven – within the EU Commission coordination framework – by national governments liaising directly with their citizens through participatory procedures, involving relevant stakeholders. Simplified implementation procedures with clear spatial targeting and limited involvement of regional authorities are necessary conditions for the avoidance of implementation delays.