Analyzing Urban Agglomeration Patterns and Economic Development in Metro Manila using Social Network Analysis

Abstract. Metro Manila, the Philippines’ largest urban agglomeration, illustrates the spatial clustering of economic activities typical of densely agglomerated regions. While core cities enjoy strong connectivity and agglomeration benefits, peripheral areas continue to experience marginalization, highlighting persistent uneven development. This study applies a gravity-based Social Network Analysis (SNA) to model intercity economic connections from 2015 to 2020, using entropy-weighted indicators and estimated transport distances to construct economic networks at three time points. The primary objective is to examine how the strength and structure of these connections have evolved and what they reveal about centralization, marginalization, and subgroup cohesion across cities. Findings confirm a strong and persistent core-periphery structure, with Makati, Manila, Pasay, and Quezon City consistently occupying dominant positions in the network. Fringe cities such as Marikina, Valenzuela, Muntinlupa and Pateros remained weakly integrated due to their peripheral location and limited connectivity to economic cores. In 2018, the network experienced a temporary decline in connectivity which is evident in lower density, efficiency, and centrality scores, before partially recovering in 2020. Central cities retained bridging roles, while others showed shifting positions over time. Cohesive subgroup analysis revealed strong intra-cluster ties but limited inter-cluster integration, reinforcing structural fragmentation. These demonstrate that proximity alone does not determine influence because functional roles, infrastructure, and institutional alignment are equally critical. Results also emphasize the need for proximity-responsive development, intercity collaboration, and investment in “bridge cities” to reduce spatial inequalities and enhance regional economic integration.