Modelling emergent structures in mobility

Modelling emergent structures in mobility

Marion Hoffman, Institute for Advanced Study in Toulouse, Toulouse School of Economics.

4th of December 2025

This seminar is jointly organized with the School of Mathematics and Statistics at University College Dublin.

Abstract: 

It is increasingly common to study the mobility and migration of individuals between social and physical locations as networks in which locations are nodes connected by mobile individuals. This conceptualisation as mobility networks facilitates the analysis of endogenous processes, in which individuals influence one another in their mobility destinations. Technically, this amounts to analysing interdependence between individuals’ mobility paths.

A recently pro1posed framework allows the statistical modelling of these social processes and, therefore, of dependence in mobility, combining features of Exponential Random Graph Models (ERGMs) and classic log-linear models.

In the first part of this talk, I will discuss how we can specify these models in a principled and theoretically informed way. I will show how we can reformulate the model under analysis as a multinomial logit with dependent observations and apply statistical theory to propose model specifications that (i) are based on clear individual-level dependence assumptions, (ii) have a clear individual-level interpretation, and (iii) avoid (near-)degeneracy, a common problem for models with dependent observations.

In the second part, I will discuss the practical value of this new modelling framework. I will examine how important endogenous processes may be in real-world mobility networks and whether omitting them may lead to misleading results.

(This is joint work with Per Block and others)