🤖 AI Summary
Existing relational event models (REMs) typically model unobserved heterogeneity at the individual level, rendering them inadequate for capturing structural differences in dyadic interactions within dynamic social networks. To address this limitation, we propose a dyadic latent class REM that introduces latent classes at the dyad level—marking the first extension of latent variable modeling from the individual to the relational level—and thereby overcomes constraints imposed by adjacency matrix representations. Parameter estimation is conducted via maximum likelihood using the EM algorithm. Simulation studies demonstrate that our model achieves significantly higher goodness-of-fit and classification accuracy compared to conventional latent-variable REMs. When applied to cross-national military conflict data, it successfully identifies distinct types of country pairs exhibiting heterogeneous conflict propensities, uncovering previously obscured structural interaction patterns that standard models fail to detect.
📝 Abstract
Dynamic social networks can be conceptualized as sequences of dyadic interactions between individuals over time. The relational event model has been the workhorse to analyze such interaction sequences in empirical social network research. When addressing possible unobserved heterogeneity in the interaction mechanisms, standard approaches, such as the stochastic block model, aim to cluster the variation at the actor level. Though useful, the implied latent structure of the adjacency matrix is restrictive which may lead to biased interpretations and insights. To address this shortcoming, we introduce a more flexible dyadic latent class relational event model (DLC-REM) that captures the unobserved heterogeneity at the dyadic level. Through numerical simulations, we provide a proof of concept demonstrating that this approach is more general than latent actor-level approaches. To illustrate the applicability of the model, we apply it to a dataset of militarized interstate conflicts between countries.