Testing and dating structural changes in copula-based dependence measures

This paper is concerned with testing and dating structural breaks in the dependence structure of multivariate time series. We consider a cumulative sum (CUSUM) type test for constant copula-based dependence measures, such as Spearman''s rank correlation and quantile dependencies. The asymptotic null distribution is not known in closed form and critical values are estimated by an i.i.d. bootstrap procedure. We analyze size and power properties in a simulation study under different dependence measure settings, such as skewed and fat-tailed distributions. To date breakpoints and to decide whether two estimated break locations belong to the same break event, we propose a pivot confidence interval procedure. Finally, we apply the test to the historical data of 10 large financial firms during the last financial crisis from 2002 to mid-2013.     

Migration information campaigns: How to analyse their impact?

Information campaigns aim at discouraging potential migrants from leaving their countries irregularly. This article discusses how to analyse the impact of such campaigns by identifying different research lines in the literature. The impact of migration information campaigns may be explored by, firstly, focusing on transnational migratory data and inter-state relations (the macro-level); secondly, by investigating their impact on narratives within societies (the meso-level); and, finally, by investigating the micro-level of their influence on migratory decision-making. At each level, scholars face considerable methodological challenges to filter out the impact of campaigns. This article suggests that a promising research avenue is to analyse more widely the narratives and information sources upon which (potential) migrants rely. Opening up the research focus may avoid the risk of over-emphasising the impact of information campaigns by only looking at them. It allows to better understand which sources of information actually influence migratory behaviour.     

Development of the Geographical Proportional-to-size Street-Intercept Sampling (GPSIS) method for recruiting urban nightlife-goers in an entire city

Abstract

We developed the Geographical Proportional-to-size Street-Intercept Sampling (GPSIS) method in order to obtain a sample of nightlife-goers which accounted for the diversity of spaces, patrons and locations within two Swiss cities. Popular nightlife zones were identified and quantified using social media data and local experts’ knowledge. Young people were recruited in the streets on Friday and Saturday nights on three consecutive weekends using the ‘fixed-line method, pro-rated for the zone’s estimated popularity. Of the 3092 young adults approached, 896 agreed to pre-register. The importance of recruitment in multiple zones and over multiple weekend-days was evidenced by significant variations in participant demographics and registration rates between recruitment zones, times and weather conditions. To conclude, by combining a geographical approach with in situ recruitment, GPSIS has considerable potential as a tool for recruiting samples that represent the diversity of the nightlife population and spaces.     

The Impact of EU Migration Policies on African Countries: the Case of Mali

This article elaborates on the impact of EU migration policies on African countries, taking Mali as a case study. Building upon fieldwork in the country, it argues that enhanced European involvement (EU and individual member states) has caused Mali to develop a more control-oriented dimension to its migration policy and to strengthen its links with European development actors and the Malian diaspora. While these reverberations of EU policies can be likened to what scholars have established for other African countries, Mali is unusual because of its large exposure to altered regional patterns of migration cooperation. Many of the regional refoulements and deportations end in Mali despite the fact (or, perhaps, because of the fact) that the official Malian state does little to regulate these operations. In the absence of official policy responses, civil society organizations have stepped in to provide returned migrants with basic care and reception.     

Enttraditionalisierung und Traditionalisierung der Arbeitsteilung im Haushalt. Beide Seiten sind wichtig

With this contribution we reply to the constructive feedback of Johannes Kopp. In doing so, we clarify that our paper “How does the division of labor change in the course of marriage” (KZfSS 58 (1), 2006) was the theoretical starting point for further longitudinal analyses of the division of housework. In a second study, though, we already conducted the analyses requested by Kopp.     

Employment Protection and Temporary Work Agencies

Employers who use temporary agency staff in contrast to regular staff are not affected by employment protection regulations when terminating a job. Therefore, services provided by temporary work agencies may be seen as a substitute for regular employment. In this paper, we analyse the effects of employment protection on the size of the temporary work agency sector in a model of equilibrium unemployment. We find that higher firing costs may even reduce temporary work agency employment if agencies themselves are subject to employment protection, a consideration that distinguishes our results from those for fixed‐term employment arrangements.     

Potential impact of COVID-19 on ongoing clinical trials: a simulation study with the neurological Yale Global Tic Severity Scale based on the CANNA-TICS study

The COVID-19 pandemic has manifold impacts on clinical trials. In response, drug regulatory agencies and public health bodies have issued guidance on how to assess potential impacts on ongoing clinical trials and stress the importance of a risk-assessment as a pre-requisite for modifications to the clinical trial conduct. This article presents a simulation study to assess the impact on the power of an ongoing clinical trial without the need to unblind trial data and compromise trial integrity. In the context of the CANNA-TICS trial, investigating the effect of nabiximols on reducing the total tic score of the Yale Global Tic Severity Scale (YGTSS-TTS) in patients with chronic tic disorders and Tourette syndrome, the impact of the two COVID-19 related intercurrent events handled by a treatment policy strategy is investigated using a multiplicative and additive data generating model. The empirical power is examined for the analysis of the YGTSS-TTS as a continuous and dichotomized endpoint using analysis techniques adjusted and unadjusted for the occurrence of the intercurrent event. In the investigated scenarios, the simulation studies showed that substantial power losses are possible, potentially making sample size increases necessary to retain sufficient power. However, we were also able to identify scenarios with only limited loss of power. By adjusting for the occurrence of the intercurrent event, the power loss could be diminished to different degrees in most scenarios. In summary, the presented risk assessment approach may support decisions on trial modifications like sample size increases, while maintaining trial integrity.