Assessing infrastructure criticality using input-output table and network analysis

Despite substantial progress in understanding infrastructure interdependencies and their economic implications, quantifying the criticality of infrastructure and its vulnerabilities to climate impacts remains challenging. Existing models often oversimplify the consequences of infrastructure failure, assuming total cessation of activities, which can lead to unrealistic risk assessments and inefficient resource allocation. This study addresses these gaps by focusing on the criticality of four infrastructure groups, energy, water, information and communication technologies (ICT), and transport, regarding economic activities and material transactions (input-output relationship). Leveraging data from the OECD Input-Output tables, the research identifies key infrastructure-related sectors based on the International Standard Industrial Classification (ISIC Rev.4) and analyzes their roles within the economy. The research begins by examining the intermediate inputs provided by infrastructure-related sectors (sectors of which activities are related to the critical infrastructure services, e.g., land transport, water supply) to all sectors across the 11 largest economies, determining which infrastructure sectors or groups generate the highest monetary flows. Subsequently, network analysis is used to evaluate the structural importance of these sectors by measuring their centrality within the economic network. To further explore their criticality, the study simulates disruptions to individual and combined infrastructure groups, assessing their impacts on network topology and economic connectivity. The findings highlight the pivotal role of the transportation and energy sectors, which together account for 70% of infrastructure-related expenditures in the economy. Among these, the energy sector emerges as the most central and influential, underscoring its critical function across all industries. A disruption in energy infrastructure could result in a 12% reduction in in-strength centrality across the network, emphasizing its widespread economic impact. Transportation infrastructure, while essential for manufacturing industries, demonstrates its criticality in enabling production and logistics. Similarly, ICT infrastructure is shown to be indispensable for service-oriented sectors, reflecting its growing importance in the modern economy. The water sector, while less centralized in its role, exhibits a dispersed yet significant influence across various industries, underscoring its essential but less direct contribution. Overall, the study advances our understanding of the economic significance and interdependence of critical infrastructure groups, providing a robust framework to evaluate their roles, vulnerabilities, and potential impacts on economic activities.