Community detection reveals multiple rich cores in Indonesia’s intranational production network

Abstract

Abstract This study examines the mesoscale organization of Indonesia’s intranational production network using the 2016 Interregional Input–Output (IRIO) table. We represent intermediate transactions as a weighted, directed supra-network of 578 province–sector nodes and combine three network tools in a single pipeline, namely consensus Leiden community detection, weighted rich-club analysis, rich-node enrichment testing, and inter-community backbone extraction. We evaluate whether production communities are primarily organized by geography or sectoral alignment, assess how economically central province–sector nodes are distributed across communities, and examine how the inter-community backbone structures national production integration. Results show that communities are predominantly geographic, aligning strongly with provinces and island groupings rather than sector labels, and therefore form spatially cohesive but multi-sector production blocs. The sector groups that dominate internal value added and external linkage channels further characterize the production-network profile of each community. This comparison identifies Java-based manufacturing production cores, Jakarta’s service-intermediation role, East Java’s hybrid service–manufacturing role, and resource-processing or resource-supplying interfaces outside Java. Rich-club and enrichment analyses show that production-network centrality is organized as a pattern of multiple spatially grounded rich-core communities rather than being absorbed into a single dominant production community. This multiple rich-core structure is Java-centered at the national mesoscale, with the island-constrained test giving the strongest support to the Jakarta-centered community. Cross-resolution results further show that selected communities outside Java, especially in resource-producing regions, exhibit supplier-side rich-node concentrations at finer spatial resolution. The inter-community backbone reveals a Java-centered strongest-corridor structure linking western, central, and eastern Indonesia through Jakarta and East Java. A redundancy-preserving PMFG comparison shows that these two communities remain structurally important gateway positions when additional high-weight routes are retained. Based on the 2016 IRIO table, the findings offer a structural snapshot of flow concentration and corridor dependence, serving as a basis for future dynamic analysis of shock propagation. Overall, the mesoscale framework provides a systematic basis for understanding how spatial production communities, rich-node concentration, and interregional gateway corridors jointly shape Indonesia’s production network, with implications for spatial inequality, national integration, and structural dependence.