Speaking Together: Explaining Collaboration Patterns Among UN Human Rights Experts

UN Special Procedures mandate holders form a dynamic collaboration network that constitutes a mostly self-organised structure within the UN human rights system. Through joint press releases and public statements, the independent experts mandated by the Human Rights Council (HRC) establish network ties that may affect advocacy effectiveness and institutional influence. This paper examines the structure and the drivers of this collaboration network. Our analysis draws on 4,230 press releases and public statements issued between October 2011 and December 2024, constructing a collaboration network among mandate holders. We employ a dyadic approach to identify factors influencing (non-)collaboration between pairs of mandate holders, and Exponential Random Graph Models to study endogenous network processes that reveal how the network structure itself shapes collaboration choices, e.g. in the form of cliques. Three explanatory mechanisms are tested: first, principal-agent dynamics, in which individual experts collaborate as delegated by their HRC mandates (operationalised through qualitative content analyses of the respective HRC resolutions). Second, homophily effects, examining whether biographical similarities, such as educational backgrounds, regional origins, and work experience, predict collaboration (exploiting the availability of application documents of all mandate holders). Third, strategic legitimacy-seeking, measured by the alignment of collaborating mandates' geopolitical profiles based on HRC voting and sponsorship patterns. Our paper addresses whether experts function primarily as agents or exercise autonomous network-building influenced by biographical characteristics and geopolitical contexts. Understanding these dynamics is particularly salient amid growing fragmentation and contestation within the multilateral human rights system, where informal networks may increasingly shape institutional effectiveness.