Goodness of fit for stochastic actor-oriented models

We propose a Mahalanobis distance–based Monte Carlo goodness of fit testing procedure for the family of stochastic actor-oriented models for social network evolution. A modified model distance estimator is proposed to help the researcher identify model extensions that will remediate poor fit. A limited simulation study is provided to establish baseline legitimacy for the Mahalanobis distance–based Monte Carlo test and modified model distance estimator. A forward model selection workflow is proposed, and this procedure is demonstrated on a real data set

Die Modellierung komplexer Netzwerke: zum Nutzen agentenbasierter Modelle in der neuen Netzwerkforschung

"Die 'neue Netzwerkforschung' argumentiert, dass große soziale Netzwerke in unterschiedlichsten Kontexten (zum Beispiel das World Wide Web, Sexualkontakte, Koautorschaften) sehr ähnliche, hocheffiziente Struktureigenschaften aufweisen ('small world' oder 'scale free' Strukturen). Darüber hinaus werden diese Strukturen als das Resultat einfachster individueller Verhaltensmechanismen gesehen, die die makroskopische Struktur als unbeabsichtigtes Nebenprodukt individueller Beziehungswahlentscheidungen erzeugen. Die Verfasser behaupten, dass diese Forschung aus Sicht der Soziologie zwei Defizite aufweist. Erstens sind die verwendeten Verhaltensmodelle soziologisch wenig plausibel. Typischerweise werden mechanistische - oftmals an physikalischen Modellen orientierte - individuelle Verhaltensregeln angenommen und die zugrundeliegenden Motive individueller Beziehungswahlen nicht explizit modelliert. Die Modelle bieten daher wenig Einsicht in die Bedingungen der behaupteten Strukturresultate. Zweitens untersuchen empirische Arbeiten üblicherweise nur, ob globale Netzwerkmerkmale in dem Bereich liegen, der durch die theoretischen Modelle vorhergesagt wird, testen aber nicht Mechanismen der Netzwerkdynamik auf der individuellen Ebene. Sie schlagen daher vor, dass soziologische 'neue Netzwerkforschung' das Instrument 'agentenbasierter Modellierung' einsetzt. Agentenbasierte Modelle beschreiben explizit die individuellen Verhaltenziele und -regeln bestenfalls beschränkt rationaler Akteure, die nur über unvollständige lokale Information verfügen. Sie zeigen an einem Beispiel auf, wie eine agentenbasierte Modellierung der Dynamik großer Netzwerke mit soziologisch plausiblen Verhaltensannahmen nicht nur die Entstehung von 'small world' und 'scale free' Strukturen erklären kann, sondern darüber hinaus auch Bedingungen identifiziert, unter denen die zugrundeliegenden Verhaltensregeln zu verschiedenen Strukturen führen. Sie gehen dann auf statistische Ansätze ein, insbesondere auf die 'actor oriented statistics', die es möglich machen, konkurrierende Verhaltenshypothesen an Netzwerkdaten zu testen." (Autorenreferat

Democratizing corruption:a role structure analysis of Indonesia’s “Big Bang” decentralization

The study investigates to what degree Indonesia’s large-scale decentralization and democratization changed corruption networks. A role structure approach is developed to move current analysis of dyad-level structures to the network level. This approach is empirically tested by comparing the relational content and third-party structures of 96 corruption networks operating in the first phase of decentralization (2001–2004), characterized by a powerful local council, with 94 corruption networks detected in the second phase (2005–2013), when direct local elections were introduced, and the power of the local council declined. Building on Fiske’s relational model theory, it is argued and found that the local executive’s reduced dependence on the local council provided the opportunity to initiate corrupt exchanges with a broader set of players both inside and outside the bureaucracy. Whereas deep dependence power relations (i.e. formal authority) remained important, an increasing proportion of corruption networks involved compound role structures characterized by both shallow (non-embedded profit and work relations) and deep interdependence (kin- and friendship). Furthermore, third party intermediaries became more important. Implications for the study of networks of corruption are discussed.</p

Determinants of safe sexual behavior of female sex workers in Tehran:the woman, her network, and the sexual partner

BACKGROUND: Despite the steady growth of sexual transmission of HIV, there is little evidence about safe sexual behavior of FSWs, and social network effects on this behavior, in Iran. Our aim in this study was to determine the effect of social network characteristics on condom use among FSWs, considering individual characteristics of the FSWs and of their sexual partners, characteristics of their relationship, and the FSW’s personal network. METHODS: A cross-sectional ego-centric network survey of 170 FSWs was carried out in Tehran between January and June 2017. A multilevel ordered logistic regression analysis was conducted to examine the effects of individual and relational characteristics simultaneously. RESULTS: Condom use in sexual relationships of the FSWs on average was rather low. Important determinants of safe sexual behavior were found both at the level of the individual FSW and at the level of the sexual partner. The main determinants at the level of the individual FSW were FSWs’ age and HIV knowledge. At the level of the sexual partner, age and education of sexual partners, as well as intimacy, duration of tie, frequency of contacts with a given partner, frequency of contact, perceived social support, and perceived safe sex norms were significantly associated with condom use. CONCLUSIONS: The findings highlighted that considering only the individual characteristics of female sex workers is not sufficient for effectively promoting condom use. Factors at the network and dyadic level should also be considered, especially the role of sexual partners. Network-based interventions may be useful which modify social relationships to create a social environment that can facilitate changes in sexual behavior

The origins of redistributive policy preferences: political socialisation with and without a welfare state

Research on the impact of the macroeconomy on individual-level preferences for redistribution has produced varying results. This paper presents a new theory on the presence of an expansive welfare state during one’s formative years as a source of heterogeneity in the effect that macroeconomic conditions have on individuals’ preferences for redistributive policy. This theory is tested using cohort analysis via the British Social Attitudes surveys (1983–2010), with generations coming of age between the end of World War I and today. Findings confirm that cohorts that were socialised before and after the introduction of the welfare state react differently to economic crises: the former become less supportive of redistribution, while the latter become more supportive. The research sheds light on the long-term shifts of support for the welfare state due to generational replacement

Do firms demand temporary workers when they face workload fluctuation? Cross-country firm-level evidence

The growth of temporary employment is one of the most important transformations of labor markets in the past decades. Theoretically, firms' exposure to short-term workload fluctuations is a major determinant of employing temporary workers when employment protection for permanent workers is high. The authors investigate this relationship empirically with establishment-level data in a broad comparative framework. They create two novel data sets by merging 1) data on 18,500 European firms with 2) measures of labor-market institutions for 20 countries. Results show that fluctuations increase the probability of hiring temporary workers by 8 percentage points in countries with strict employment protection laws. No such effect is observed in countries with weaker employment protections. Results are robust to subgroups, subsamples, and alternative estimation strategies