Tom Snijders

Tom Snijders
University of Groningen | RUG · Department of Sociology

PhD

About

64
Publications
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4,233
Citations

Publications

Publications (64)
Article
Full-text available
Success for All (SfA) is a comprehensive school reform program with a strong emphasis on cooperative learning that aims to improve students’ social emotional learning alongside students’ cognitive learning. In the present study it was examined whether SfA led to improved students’ social behavior in Grade 1–3 of primary education. Peer sociometric...
Article
This study examines ethnic integration in secondary school. Social identity theory suggests that perception of relevant individual attributes plays a crucial role in defining ingroups and outgroups, contributing to befriending, and disliking others. Therefore, we analyze the role of peer-perceived ethnicity in social ties. Networks of friendship, d...
Article
Full-text available
It was examined whether cooperative learning within the Success for All (SfA) program led to improved group work behaviour of Grade 1 pupils. 168 pupils of six SfA schools and 144 pupils of four control schools participated. Positive and negative group work behaviour was observed during a group task, taking into account socioemotional ethos, group...
Article
Full-text available
We propose two complementary ways to deal with a nesting structure in the node set of a network — such a structure may be called a multilevel network, with a node set consisting of several groups. First, within‐group ties are distinguished from between‐group ties by considering them as two distinct but interrelated networks. Second, effects of noda...
Data
Bolt, D. (2003). Book review of A. Boomsma, M.A.J. van Duijn & T.A.B. Snijders (Eds.). (2000). Essays on item response theory. New York: Springer. Psychometrika, 68 (1), 155-158.
Article
Full-text available
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 base...
Article
This paper addresses the formation of social norms of cooperation through interaction in repeated Public Goods Games, using novel multilevel techniques. Cooperation has traditionally been understood as the interplay of static factors such as shared social identity and pre-existing norms. This study investigates the dynamic emergence of cooperative...
Article
Full-text available
This study examined how classroom peer relations can be described in terms of the network of help relations among students, and the positions students take up in this help network, and whether the structure of adolescent classroom help networks and individual network positions were associated with academic achievement. Help networks were based on t...
Preprint
Full-text available
We consider the specification of effects of numerical actor attributes in statistical models for directed social networks. A fundamental mechanism is homophily or assortativity, where actors have a higher likelihood to be tied with others having similar values of the variable under study. But there are other mechanisms that may also play a role in...
Article
Full-text available
This paper proposes that common measures for network transitivity, based on the enumeration of transitive triples, do not reflect the theoretical statements about transitivity they aim to describe. These statements are often formulated as comparative conditional probabilities, but these are not directly reflected by simple functions of enumerations...
Chapter
Multilevel analysis and social network analysis both represent social structure, and have led to statistical methodologies departing from the traditional atomic approach to social systems that is implied by linear regression analysis. There are various ways in which multilevel considerations are important for social network analysis. This chapter s...
Book
This volume provides new insights into the functioning of organizational, managerial and market societies. Multilevel analysis and social network analysis are described and the authors show how they can be combined in developing the theory, methods and empirical applications of the social sciences. This book maps out the development of multilevel r...
Article
Full-text available
The complex interplay between bullying/victimization and defending was examined using a longitudinal social network approach (stochastic actor-based models). The (co)evolution of these relations within three elementary schools (Grades 2-5 at Time 1, ages 8-11, N = 354 children) was investigated across three time points within a year. Most bullies a...
Article
Glossary Definition of the Subject Introduction Stochastic Models for Network Dynamics Statistical Estimation and Testing Example: Dynamics of Adolescent Friendship Models for the Co‐evolution of Networks and Behavior Example: Co‐evolution of Adolescent Friendship and Alcohol Use Extensions Future Directions Bibliography
Article
Full-text available
Longitudinal social networks are increasingly given by event data; i.e., data coding the time and type of interaction between social actors. Examples include networks stemming from computer-mediated communication, open collaboration in wikis, phone call data and interaction among political actors. In this paper, we propose a general model for netwo...
Article
Full-text available
Three relations between elementary school children were investigated: networks of general dislike and bullying were related to networks of general like. These were modeled using multivariate cross-sectional (statistical) network models. Exponential random graph models for a sample of 18 classrooms, numbering 393 students, were summarized using meta...
Article
Full-text available
The issue of the influence of norms on behavior is as old as sociology itself. This paper explores the effect of normative homophily (i.e. “sharing the same normative choices”) on the evolution of the advice network among lay judges in a courthouse. (Blau, 1955) and (Blau, 1964) social exchange theory suggests that members select advisors based on...
Article
Full-text available
Studies of peer effects in educational settings confront two main problems. The first is the presence of endogenous sorting which confounds the effects of social influence and social selection on individual attainment. The second is how to account for the local network dependencies through which peer effects influence individual behavior. We empiri...
Article
Full-text available
This paper explores time heterogeneity in stochastic actor oriented models (SAOM) proposed by Snijders (Sociological Methodology. Blackwell, Boston, pp 361-395, 2001) which are meant to study the evolution of networks. SAOMs model social networks as directed graphs with nodes representing people, organizations, etc., and dichotomous relations repre...
Article
Full-text available
A model for network panel data is discussed, based on the assumption that the observed data are discrete observations of a continuous-time Markov process on the space of all directed graphs on a given node set, in which changes in tie variables are independent conditional on the current graph. The model for tie changes is parametric and designed fo...
Article
Stochastic actor-based models are models for network dynamics that can represent a wide variety of influences on network change, and allow to estimate parameters expressing such influences, and test corresponding hypotheses. The nodes in the network represent social actors, and the collection of ties represents a social relation. The assumptions po...
Article
The p(2) model is a statistical model for the analysis of binary relational data with covariates, as occur in social network studies. It can be characterized as a multinomial regression model with crossed random effects that reflect actor heterogeneity and dependence between the ties from and to the same actor in the network. Three Markov chain Mon...
Book
Full-text available
Les échanges sociaux s’inscrivent nécessairement dans le temps – la durée nécessaire, par exemple, à la réciprocité directe ou indirecte ou à la négociation et renégociation des règles et des termes de ces échanges. Les réseaux sociaux, qui représentent des systèmes d’échanges et d’interdépendances, sont donc dynamiques par nature. (...) Tous les a...
Article
Full-text available
Networks and controversies : on the effect of norms on the dynamics of structures. The issue of the influence of norms on behaviour is as old as sociology itself. Institutional theorists, such as Selznick (1957), theorized this influence in terms of « precarious values ». This paper uses this classical view to bring in structure between norms and b...
Article
A parametric, continuous-time Markov model for digraph panel data is considered. The parameter is estimated by the method of moments. A convenient method for estimating the variance–covariance matrix of the moment estimator relies on the delta method, requiring the Jacobian matrix—that is, the matrix of partial derivatives—of the estimating functio...
Article
Full-text available
A deeper understanding of the relation between individual behavior and individual actions on one hand and the embeddedness of individ- uals in social structures on the other hand can be obtained by em- pirically studying the dynamics of individual outcomes and network structure, and how these mutually aect each other. In methodolog- ical terms, thi...
Article
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We give a non-technical introduction into recently developed methods for analyzing the co-evolution of social networks and behavior(s) of the network actors. This co-evolution is crucial for a variety of research topics that currently receive a lot of attention, such as the role of peer groups in adolescent development. A family of dynamic actor-dr...
Article
Full-text available
The p2 model is a random effects model with covariates for the analysis of binary directed social network data coming from a single observation of a social network. Here, a multilevel variant of the p2 model is proposed for the case of multiple observations of social networks, for example, in a sample of schools. The multilevel p2 model defines an...
Article
With the development of an MCMC algorithm, Bayesian model selection for the p2 model for directed graphs has become possible. This paper presents an empirical exploration in using approximate Bayes factors for model selection. For a social network of Dutch secondary school pupils from different ethnic backgrounds it is investigated whether pupils r...
Article
A random effects model is proposed for the analysis of binary dyadic data that represent a social network or directed graph, using nodal and/or dyadic attributes as covariates. The network structure is reflected by modeling the dependence between the relations to and from the same actor or node. Parameter estimates are proposed that are based on an...
Article
A random e#ects model is proposed for the analysis of binary dyadic data that represent a social network or directed graph, using nodal and/or dyadic attributes as covariates. The network structure is reflected by modeling the dependence between the relations to and from the same actor or node. Parameter estimates are proposed that are based on an...
Article
A class of statistical models is proposed that aims to recover latent settings structures in social networks. Settings may be regarded as clusters of vertices. The measurement model is based on two assumptions. (1) The observed network is generated by hierarchically nested latent transitive structures, expressed by ultrametrics, and (2) the expecte...
Article
Full-text available
This paper considers only models with such a conditioning
Article
In a study of conflict in organizations, Lindenberg’s relational signaling theory is used to develop hypotheses on the impact of relationship strength, network embeddedness, and organizational change on social escalation. Social escalation is defined as the involvement of one or more third parties in a conflict. An empirical test is conducted with...
Article
The present longitudinal study aims to explain emotional and social loneliness experienced by older adults (N=99) during two-and-a-half years of widowhood. Utilization of multilevel analysis and a “visual” cluster analysis with prescribed classification criteria enabled us to search for average adaptational developments as well as individual variab...
Article
Full-text available
The unidimensional nature of the De Jong-Gierveld Loneliness Scale is investigated. The internal properties of the scale scores were studied using item response theory, supplemented by an external validity study. In line with the theory of relational loneliness, the results stress the significance of distinguishing between emotional loneliness and...
Book
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Contents and abstracts of all book chapters are available here and at https://aboomsma.webhosting.rug.nl/irt.htm. See also the linked data for a review of the book: Bolt, D. (2003). Book review of A. Boomsma, M.A.J. van Duijn & T.A.B. Snijders (Eds.). (2000). Essays on item response theory. New York: Springer. Psychometrika, 68 (1), 155-158.
Article
Full-text available
We propose a class of actor-oriented statistical models for closed social networks in general, and friendship networks in particular. The models are random utility models developed within a rational choice framework. Based on social psychological and sociological theories about friendship, mathematical functions capturing expected utility of indivi...
Article
Full-text available
This longitudinal study aims to explain loneliness in newly bereaved older adults, taking into account personal and circumstantial conditions surrounding the partner's death. A distinction is made between emotional and social loneliness. Data were gathered both before and after partner loss. Results were interpreted within the framework of the...
Article
Full-text available
This study employs a multidisciplinary model to explain the adoption of agricultural innovations in developing economies with reference to hybrid cocoa in Ghana. The empirical evidence shows that, in the adoption of hybrid cocoa, the support that small-scale farmers obtain via their social networks is more relevant than the advantage of farm size e...
Article
Psychiatric patients generally report more adverse recollections of their parents' rearing behaviour than individuals from the general community. It is, however, as yet unclear whether we can infer from this finding that the families of psychiatric patients differ from the families of healthy controls, that is, whether patients' adverse views are s...
Article
Full-text available
Digraph panel data (arcs between vertices observed at two or more time points) arise in the social sciences and other fields of scientific inquiry. A popular approach to model such data is to embed the discrete observations of the random digraph into an unobserved, continuous-time Markov process. A large and appealing family of Markov probability m...

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