Stochastic Actor-oriented Models Research Articles

Political Alliance Formation and Cooperation Networks in the Utah State Legislature.

Social network analysis has become an increasingly important tool among political scientists for understanding legislative cooperation in modern, democratic nation-states. Recent research has demonstrated the influence that group affinity (homophily) and mutual exchanges (reciprocity) have in structuring political relationships. However, this literature has typically focused on political cooperation where costs are low, relationships are not exclusive, and/or partisan competition is high. Patterns of legislative behavior in alternative contexts are less clear and remain largely unexamined. Here, we compare theoretical expectations of cooperation in these contexts from the political and biosocial sciences and implement the first assessment of political alliance formation in a novel legislative environment where costs to cooperation are high and party salience low. We implement a stochastic actor-oriented model (SAOM) to examine bill floor sponsorship, a process in which a "floor sponsor" becomes the exclusive advocate for a colleague's piece of legislation, in the Utah state legislature from 2005 to 2008-a context in which gender (male) and political party (Republican) supermajorities exist. We find that (1) party and gender homophily predict who legislators recruit as floor sponsors, whereas seniority does not, and (2) legislators frequently engage in reciprocal exchanges of floor sponsorship. In addition, whereas gender homophily increases the likelihood of reciprocity, party homophily decreases it. Our findings suggest that when the cost of cooperation is high, political actors use in-group characteristics for initiating alliances, but once a cooperative relationship is established with an out-group political member, it is reinforced through repeated exchanges. These findings may be useful for understanding the rise of political polarization and gridlock in democracies internationally.

How do youth choose activities? Assessing the relative importance of the micro-selection mechanisms behind adolescent extracurricular activity participation

We investigate the network micro-selection mechanisms responsible for patterns of high school student extracurricular activity (ECA) participation, with a particular focus on those that can lead to ethnoracial segregation. We identify six types of mechanisms by which students select into activities (e.g., peer influence, homophily), which we test using a unique longitudinal dataset that combines student surveys with yearbook data on ECA involvement. These contexts represent two ethnoracially diverse U.S. high schools involving 2403 students and over 200 different activities spanning two school years. Using a stochastic actor-oriented model for two-mode networks, we find support for the hypothesized activity selection mechanisms. Follow-up analyses convey the relative importance of different mechanisms and inform our discussion of how ECA participation patterns develop and possible sources of segregation. Whereas selection is driven by mechanisms that include influence from friends and co-participants and similarity to fellow participants, no single overarching mechanism appears strong enough to fully account for ECA segregation

The role of full- and half-day preschool attendance in the formation of children's social networks

In the United States, the duration of children's preschool attendance differs, with some children attending full-day preschool and some children attending half-day preschool. This difference provides uneven daily exposure to peers that may have implications for childhood social outcomes, including the formation of social networks over time. In this study, we examined the role of full- and half-day preschool attendance in children's social network formation. Specifically, using stochastic actor-oriented modeling (i.e., a type of longitudinal social network analysis appropriate for measuring relationship formation over time), we analyzed longitudinal social network data from an intensive observational study of 25 three-year-old and 28 four-year-old students’ social play relationships in 2 preschool classrooms over the course of an entire school year. Our results provide no evidence that attending full-day preschool has a positive effect on the formation of social play relationships in early childhood. Instead, 3-year-old children who attended full-day preschool were significantly less likely than their half-day peers to form social play relationships over time. We discuss potential developmental and contextual factors that might explain this finding as well as future directions for research and practice.

Structural Characteristics and Evolutionary Drivers of Global Virtual Water Trade Networks: A Stochastic Actor-Oriented Model for 2000-2015

Structural Characteristics and Evolutionary Drivers of Global Virtual Water Trade Networks: A Stochastic Actor-Oriented Model for 2000-2015

Contextualizing oppositional cultures: The variable significance of gender and ethnic minority status across schools

Different lines of research have argued that specific groups, such as boys or ethnic minorities, are more prone to develop an anti-school culture than others, leading to group differences in the social acceptance of high performers. Taking an ecological view, we ask to what extent the school context promotes or prevents the emergence of group-specific oppositional cultures. Theoretically, we argue that group-based oppositional cultures become more likely in schools with low socio-economic resources and in schools where socio-economic differences align with demographic attributes. We test our hypotheses based on data from a large-scale, four-wave network panel survey among more than 4000 students in Germany. Applying stochastic actor-oriented models for the coevolution of networks and behavior, we find that group-based oppositional cultures in which students like high performers less are very rare. However, in line with theoretical expectations, the less resourceful a school is, the more boys tend to evaluate high-performing peers less positively than girls do. Moreover, the more ethnic minority boys are socioeconomically disdvantaged in a school, the more they tend to evaluate high performers less positively than majority boys do.

The development of university teachers’ collaboration networks during a departmental professional development project

Professional interaction in the workplace is an indispensable part of professional development. We examined how teachers' teaching collaboration networks within a university department changed throughout an eight-month professional development project and how these networks influenced teachers’ observation choices in formative peer observations. Stochastic actor-oriented modeling (SAOM) shows that it was more likely that teachers started to collaborate when they were working on the same floor (propinquity), were more active in attending project meetings, and had more teaching experience. The multiple regression quadratic assignment procedure (MR-QAP) indicates that teachers were more likely to observe colleagues with whom they already collaborated.

Modeling Diffusion through Statistical Network Analysis: A Simulation Study and Empirical Application to Same-Sex Marriage

Abstract The study of international relations by definition deals with interdependencies among countries. One form of interdependence between countries is the diffusion of country-level features, such as policies, political regimes, or conflict. In these studies, the outcome variable tends to be categorical, and the primary concern is the clustering of the outcome variable among connected countries. Statistically, such clustering is studied with spatial econometric models. This article instead proposes the use of a statistical network approach to model diffusion with a binary outcome variable. Using a statistical network instead of spatial econometric models allows for modeling autocorrelation in policy outcomes rather than the corresponding latent variable, and it simplifies the inclusion of temporal dynamics, higher level interdependencies, and interactions between network ties and country-level features. In our simulations, the performance of the Stochastic Actor-Oriented Model (SAOM) estimator is evaluated. Our simulation results show that spatial parameters and coefficients on additional covariates in a static binary spatial autoregressive model are accurately recovered when using SAOM. To demonstrate this model, the paper applies SAOM to original data on the international diffusion of same-sex marriage and gives practical instructions for using such models.

Being Popular or Having Popular Friends, Which Is Better? A Longitudinal Social Network Analysis of Depressive Symptoms among Chinese Adolescents under Major Chronic Stress.

Background: Previous studies have found that adolescents’ depressive symptoms are influenced by social networks in a stressful context, especially focusing on the processes of social selection and social influence. The current study aimed to explore the coevolution of sociometric popularity and depressive symptoms among adolescents suffering from the stress attached to the Chinese gaokao. Methods: The analytical sample comprised 1062 Chinese adolescents who were under significant pressure to return to school for an additional year (returnees) to prepare for college entrance examinations. Students were assessed for depressive symptoms and asked to nominate up to five friends within their classes across four waves (six months). We employed stochastic actor-oriented models to investigate the interdependent relationships between popularity and depressive symptoms. Results: Adolescents’ depressive symptoms negatively predicted future friendship popularity in this stressful situation, but not vice versa. The results of this study also highlighted the importance of friends’ popularity, indicating that adolescents who nominated popular peers as friends tended to subsequently have lower depressive symptoms. Conclusion: These findings suggested that friends’ popularity may serve as a protective factor against depressive symptoms under major chronic stress. Network-based interventions may have practical implications for reducing depressive symptoms under major chronic stress.

Effects of social networks on interventions to change conservation behavior.

Social networks are critical to the success of behavioral interventions in conservation because network processes such as information flows and social influence can enable behavior change to spread beyond a targeted group. We investigated these mechanisms in the context of a social marketing campaign to promote a wildlife poisoning hotline in Cambodia. With questionnaire surveys we measured a social network and knowledge and constructs from the theory of planned behavior at 3 points over 6 months. The intervention initially targeted ∼11% (of 365) of the village, but after 6 months ∼40% of the population was knowledgeable about the campaign. The likelihood of being knowledgeable nearly doubled with each additional knowledgeable household member. In the short term, there was also a modest, but widespread improvement in proconservation behavioral intentions, but this did not persist after 6 months. Estimates from stochastic actor-oriented models suggested that the influences of social peers, rather than knowledge, were driving changes in intention and contributed to the failure to change behavioral intention in the long term, despite lasting changes in attitudes and perceived norms. Our results point to the importance of accounting for the interaction between networks and behavior when designing conservation interventions.

Social Environment and Academic Performance: A Systematic Review of Stochastic Actor-Oriented Research

Academic achievements play an important role in an individual’s professional development, and are also considered one of the main characteristics of an education system. Academic achievements are associated with multiple factors, including the social environment of students. In this paper we review the studies that use stochastic actororiented models to examine the effects of social networks on academic achievements. We consider both the results and designs of existing studies and outline potential avenues for future research. We demonstrate that the majority of studies analyze the networks of positive relationships in schools. Only a few studies are based on data from universities. We also conclude that the majority of studies are based on data from western democracies. These findings can be considered as a basis for further empirical analysis.

Stochastic actor-oriented modelling of the impact of COVID-19 on financial network evolution.

The coronavirus disease 2019 (COVID‐19) pandemic has led to tremendous loss of human life and has severe social and economic impacts worldwide. The spread of the disease has also caused dramatic uncertainty in financial markets, especially in the early stages of the pandemic. In this paper, we adopt the stochastic actor‐oriented model (SAOM) to model dynamic/longitudinal financial networks with the covariates constructed from the network statistics of COVID‐19 dynamic pandemic networks. Our findings provide evidence that the transmission risk of the COVID‐19, measured in the transformed pandemic risk scores, is a main explanatory factor of financial network connectedness from March to May 2020. The pandemic statistics and transformed pandemic risk scores can give early signs of the intense connectedness of the financial markets in mid‐March 2020. We can make use of the SAOM approach to predict possible financial contagion using pandemic network statistics and transformed pandemic risk scores of the COVID‐19 and other pandemics.

Peer selection and influence for marijuana use in a complete network of first-year college students

BackgroundMarijuana is the most frequently used illicit drug among college students, and there is a need to understand the social processes that contribute to young adults’ marijuana use. Substance use behaviors tend to be more similar (homophilous) among individuals with social ties to one another. However, little is known about whether marijuana use homophily within young adult relationships is due to social selection (seeking out ties with similar marijuana use to one’s own) or social influence (adopting similar marijuana use behaviors as one’s ties), or both. Methods: Students (N = 1,489; 54.6% female; Mage = 18.6 years) at one University completed online surveys in their first three semesters of college. Surveys assessed participant characteristics, marijuana use, and ties to up to 10 other students in the whole (sociocentric) network of first-year college students. Stochastic-actor oriented models (SAOMs) were used to analyze the co-evolution of marijuana use and social ties over time. Results: Participants were more likely to select peers with similar past 30-day marijuana use as themselves. Concurrently, students’ past 30-day marijuana use became more similar to their peers’ use over time. Discussion: Evidence for selection and influence effects were highly significant after controlling for network structure and other covariates indicating these processes may work in tandem to increase marijuana use homophily over the first year of college. This highlights the importance of relationships made early in the first-year of college, as these initial peer ties are likely to reinforce marijuana use behaviors that occur within these relationships.

A substitute for poor institutions? Interorganizational affiliations in the alliance formation process

PurposeThis study aims to investigate how the home country institutional development influences the alliance formation process.Design/methodology/approachA network of strategic alliances between 95 airlines over a 5-year period is analyzed with stochastic actor-oriented models [i.e. Simulation investigation for empirical network analysis (SIENA)]. Robustness analyses use a subsample of these airlines over a period of 10 years.FindingsThe results demonstrate that the membership in a firm group and a high share of state ownership are more beneficial for the number of alliances if the firm originates from a country with low institutional development.Practical implicationsFirms from less developed countries can use affiliations (e.g. to firm groups or the government) as signals to attract international alliance partners.Social implicationsPolicymakers from less developed countries should support the development of (local) firm groups to stimulate interorganizational cooperation.Originality/valueFirms form alliances based on two aspects: preferences for alliance partners and attractiveness to potential partners. Prior studies outlined that institutional development affects the preferences of firms for alliance partners. This study demonstrates how the institutional development influences the attractiveness to potential partners.

RETRACTED: “Adolescents who feel depressed are rejected but do not withdraw: A longitudinal study of ethnically diverse friendship networks in England, Sweden, and Germany”

Adolescents who feel depressed are likely to experience social isolation from friends. Previous studies have put forward at least four hypotheses that can account for the association between felt depression and social isolation. The hypotheses are: (1) adolescents who are rejected tend to feel more depressed, (2) adolescents who feel depressed tend to become rejected, (3) adolescents who withdraw from friends tend to feel more depressed, and (4) adolescents who feel depressed tend to withdraw from friends. The present study aims to test these four hypotheses in ethnically diverse contexts in three countries. Two waves of data from England (n = 515), Sweden (n = 1,228), and Germany (n = 869) were obtained from the Children of Immigrants Longitudinal Survey in Four European Countries (CILS4EU). One separate stochastic actor-oriented model of the longitudinal coevolution of friendship networks and felt depression was estimated for each of the three countries using the statistical package RSiena. The results consistently indicated that, in all three countries, adolescents who felt depressed were rejected by their peers. Also, the results consistently indicated that adolescents who felt depressed sought more friends, and the results therefore refuted the suggestion that adolescents who feel depressed withdraw from their friends. The findings of the study can inform health-promotion interventions that attempt to limit the social isolation of adolescents who feel depressed in ethnically diverse contexts. More specifically, the study suggests that the social isolation of adolescents who feel depressed may be limited through interventions that reduce the rejection that these adolescents experience from their peers.

Social Networks and Entrepreneurial Passion: Selection or Contagion?

Entrepreneurial passion is contagious such that social interaction leads to passion convergence. However, do entrepreneurs also select whom they interact with based on passion similarity? The complex interdependencies between social networks and passion remain undertheorized and empirically puzzling. Using a stochastic actor-oriented model (SIENA) and four waves of panel data, we test hypotheses about the co-evolution of social networks and entrepreneurial passion during a 5-months university-based acceleration program. We find that entrepreneurs select social network ties based on similar levels of passion for founding and inventing but that only passion for founding is socially contagious. We discuss theoretical, empirical, and practical implications.

Stronger through Agreement: The Role of Consensus in Social Influence on Work-related Stress

Stress in the workplace is prevalent and an important concern in organizational practice. Apart from being shaped by situational factors and individual propensities, people’s stress experiences are affected by their social contacts via interactions. Little is known about how compositional features of one’s local network amplify or dampen the strength of this social force. Adopting a network perspective, we propose that the degree of peer consensus in stress perceptions positively moderates individuals’ susceptibility to peer influence. We conducted a 6-month longitudinal study of the coevolution of psychological stress and social ties applying stochastic actor-oriented models. Our analysis supported the moderation hypothesis: The higher the variance of stress scores among peers was (i.e., the lower the consensus), the less the focal person was influenced by his/her peers’ stress. Our work establishes that consensus amplifies the power of peer influence on stress development.

Workplace Gossip and the Evolution of Friendship Relations: The Role of Complex Contagion

Complex contagion theory is used to develop novel hypotheses on the effects of workplace gossip on expressive relations. It is argued that hearing gossip from multiple senders or about multiple targets impacts receivers’ friendships with gossip targets. Hypotheses are tested in a two-wave sociometric panel study among 148 employees of three units in a Dutch childcare organisation. Stochastic Actor-oriented Models yield only very weak support for simple contagion processes, with positive gossip fostering receiver-target friendships in one, and negative gossip significantly decreasing them in another of the three Departments. No support was found for complex contagion effects based on multiple senders. Findings for complex contagion based on multiple targets were inconsistent. Implications for theories of gossip and reputation are discussed.

Beyond cultural and geographical proximity: delving into the factors that influence the dynamics of academic relationships between students in higher education

Scholars have widely recognised the importance of academic relationships between students at the university. While much of the past research has focused on studying their influence on different aspects such as the students’ academic performance or their emotional stability, less is known about their dynamics and the factors that influence the formation and dissolution of linkages between university students in academic networks. In this paper, we try to shed light on this issue by exploring through stochastic actor-oriented models and student-level data the influence that a set of proximity factors may have on formation of these relationships over the entire period in which students are enrolled at the university. Our findings confirm that the establishment of academic relationships is derived, in part, from a wide range of proximity dimensions of a social, personal, geographical, cultural and academic nature. Furthermore, and unlike previous studies, this research also empirically confirms that the specific stage in which the student is at the university determines the influence of these proximity factors on the dynamics of academic relationships. In this regard, beyond cultural and geographic proximities that only influence the first years at the university, students shape their relationships as they progress in their studies from similarities in more strategic aspects such as academic and personal closeness. These results may have significant implications for both academic research and university policies.

Dynamic interdependence of advice seeking, loaning, and recovery characteristics in recovery homes

ABSTRACT Recovery homes in the US provide stable housing for over 250,000 individuals with past histories of homelessness, psychiatric comorbidity and criminal justice involvement. We need to know more about how these settings help those who remain in recovery. Our study measured advice seeking and willingness-to-loan relationships, and operationalized them as a dynamic multiplex social network—multiple, simultaneous interdependent relationships—that exist within 42 Oxford House recovery homes over time. By pooling relationship dynamics across recovery houses, a Stochastic Actor-Oriented Modeling (SAOM) framework was used to estimate a set of parameters governing the evolution of the network and the recovery attributes of the nodes simultaneously. Findings indicated that advice and loan relationships and recovery-related attitudes were endogenously interdependent, and these results were affected exogenously by gender, ethnicity, and reason for leaving the recovery houses. Prior findings had indicated that higher advice seeking in recovery houses was related to higher levels of stress with more negative outcomes. However, the current study found that recovery is enhanced over time if advice was sought from residents with higher recovery scores. Our study shows that social embedding, i.e., one’s position in relationship networks affects recovery prospects. More specifically, the formation of ties with relatively more recovered residents is an important predictor of better outcomes.

Insight into Selecting Adolescents for Drinking Intervention Programs: a Simulation Based on Stochastic Actor-Oriented Models.

Adolescent drinking remains a prominent public health and socioeconomic issue in the USA with costly consequences. While numerous drinking intervention programs have been developed, there is little guidance whether certain strategies of participant recruitment are more effective than others. The current study aims at addressing this gap in the literature using a computer simulation approach, a more cost-effective method than employing actual interventions. We first estimate stochastic actor-oriented models for two schools from the National Longitudinal Study of Adolescent to Adult Health (Add Health). We then employ different strategies for selecting adolescents for the intervention (either based on their drinking levels or their positions in the school network) and simulate the estimated model forward in time to assess the aggregated level of drinking in the school at a later time point. The results suggest that selecting moderate or heavy drinkers for the intervention produces better results compared to selecting casual or light drinkers. The intervention results are improved further if network position information is taken into account, as selecting drinking adolescents with higher in-degree or higher eigenvector centrality values for intervention yields the best results. Results from this study help elucidate participant selection criteria and targeted network intervention strategies for drinking intervention programs in the USA.