Evolving connections: Understanding the dynamics behind the Sino-foreign sister city network

Sister city relationships bolster trust and facilitate deeper interactions between international cities, acting as key enablers for transnational cooperation. However, less is known about the driving factors for the dynamic evolution of sister city networks. Accordingly, our study leverages data from Sino-foreign sister cities and applies the stochastic actor-oriented model (SAOM) to analyze the evolution process of these networks. We examine the driving roles of network structure characteristics, sister city attributes, and control variables. Key findings include that network density (outdegree) positively and insignificantly influences the formation of these networks, while activity plus popularity foster these connections. For city attributes, institutional distance and geographical similarity (both coastal cities) play a positive driving force in the development of sister cities. By contrast, cultural distance similarity negatively affects the dynamic development of these ties. Most interestingly, three control variables exhibit different effects on Sino-foreign sister city networks. Economic level and opening-up degree of cities exert positive and significant effects on the evolution of networks. By comparison, the effect of resource endowment of cities on network evolution presents a negative and significant driving force. In addition, this study also examines spatial heterogeneity in the evolution of Sino-foreign sister city relationships across different continents. These findings can help urban diplomacy practitioners to formulate and implement sister city planning policies and promote the efficiency of Sino-foreign cities in establishing sister city relationships.