井上 寛康

This study simulates how the disruption of imports from various regions affects the total production of the importer economy. We particularly incorporate the propagation of the economic effect through domestic supply chains using data on more than one million firms and four million supply chain ties in Japan. Our findings are summarized as follows. First, the negative effect of the disruption of intermediate imports grows exponentially as its duration and strength increase due to downstream propagation. Second, the propagation of the economic effect is substantially affected by the network topology of importers, such as the number of importers (affected nodes) and their degree of upstreamness in supply chains, whereas the effect of their degree centrality is heterogeneous depending on their degree of upstreamness. Finally, the negative effect of import disruption can be mitigated by the reorganization of domestic supply chains, even when conducted only among network neighbors. Our findings provide important policy and managerial implications for the achievement of more robust and resilient global supply chains.

In this paper, we simulate the economic loss resulting from supply chain disruptions triggered by the Great East Japan Earthquake (GEJE) in 2011, applying data from firm-level supply chains and establishment-level attributes to an agent-based model. To enhance the accuracy of the simulation, we extend data and models in previous studies in four ways. First, we identify the damage to production facilities in the disaster-hit regions more accurately by using establishment-level census and survey data and geographic information system (GIS) data on the damages caused by the GEJE and subsequent tsunami. Second, the use of establishment-level data enables us to capture supply chains between non-headquarter establishments in disaster-hit regions and establishments in other regions. Third, we incorporate the effect of power outages after the GEJE on production reduction, which exacerbated the effect of the supply chain disruption, particularly in the weeks immediately after the GEJE. Finally, our model incorporates sectoral heterogeneity by employing sector-specific parameters. Our findings indicate that the extended method can significantly improve the accuracy of predicting the domestic production after the GEJE, particularly due to the first three improvements utilizing various data sources, not because of the use of more sector-specific parameters. Our method can be applied to predict the economic effect of future disasters, such as the Nankai Trough earthquake, on each region more precisely.

Abstract Using multinational input–output data, we analyze how the productivity of countries adjusted for participation in global value chains affects their output growth in manufacturing sectors. Based on parametric and non-parametric methods, we find that value-chain linkages are critical to the productivity–growth nexus and help to explain cross-country differences in sectoral output growth rates compared to the situation where these linkages are ignored. Our results have implications for macroeconomics, where they point to peer effects in productivity as drivers of growth, and for economic development, where they illustrate how the participation in global value chains may outweigh disadvantages in productive performance at the level of individual countries. They may also encourage future empirical tests of replicator dynamics to verify whether global value chains can explain the weak evidence of selection forces at the firm level.

To prevent the spread of COVID-19, many governments have imposed lockdowns. This practice has resulted in economic stagnation across broad areas because of the shock of the lockdown propagated to other regions through supply chains. Using supply-chain data for 1.6 million firms in Japan, this study examines how the economic effects of lockdowns in multiple regions interact with each other. Our major findings are twofold. First, when multiple regions coordinate the timing of their lockdowns, their economic losses are smaller than when they do so asynchronously. Second, the benefit of synchronous lockdown in multiple regions is larger when they are connected through a larger number of supply-chain links. Our results suggest a need for policy coordination across regions and countries when lockdowns are imposed.

This study shows how import and export shocks propagate through domestic supply chains using actual Japanese supply-chain data and a world input-output table (WIOT) based on firm-level agent-based simulations. We propose three different models with which to connect the domestic firms to a WIOT. Then, we estimate the value-added losses of Japanese firms caused by shocks of different magnitudes and durations originating in China, in the EU and the US, and globally. The volume and rates at which losses increase are very different across the connection models, which indicates that the assignment of international connections to firms matters greatly. The losses increase sublinearly as the duration expands, which indicates that the shock propagation ultimately saturates the economy. Rates of saturation differ substantially depending on the assignment of international connections. The losses increase superlinearly as the initial reduction rate increases. This occurs because there is a greater probability of one supplier being replaced by other suppliers if the reduction is smaller.

<title>Abstract</title>In this study, we investigate the flow of money among bank accounts possessed by firms in a region by employing an exhaustive list of all the bank transfers in a regional bank in Japan, to clarify how the network of money flow is related to the economic activities of the firms. The network statistics and structures are examined and shown to be similar to those of a nationwide production network. Specifically, the bowtie analysis indicates what we refer to as a “walnut” structure with core and upstream/downstream components. To quantify the location of an individual account in the network, we used the Hodge decomposition method and found that the Hodge potential of the account has a significant correlation to its position in the bowtie structure as well as to its net flow of incoming and outgoing money and links, namely the net demand/supply of individual accounts. In addition, we used non-negative matrix factorization to identify important factors underlying the entire flow of money; it can be interpreted that these factors are associated with regional economic activities. One factor has a feature whereby the remittance source is localized to the largest city in the region, while the destination is scattered. The other factors correspond to the economic activities specific to different local places. This study serves as a basis for further investigation on the relationship between money flow and economic activities of firms.

Diversifying supply chains has been a policy objective of the Japanese government to construct a robust and resilient economy since the spread of COVID-19 in the final stages of the Abe Administration. Although geographically expanded supply chains incur a risk of inflows of negative economic shocks from other regions and countries, this risk can be alleviated by more diversification. In addition, diversified supply chains are found to promote the performance of firms. Recently, the domestic supply chains of Japanese firms started to be diversified, but firms still agglomerate in Tokyo substantially. Moreover, the international supply chains of Japanese firms rely considerably on Chinese suppliers and clients. Therefore, more geographic diversification of supply chains of Japanese firms is suggested for the more robust, resilient, and high-growth economy in the post Abenomics period, including diversifying within Japan, reducing the reliance on China, and strengthening links with developed countries, with the help of the government.

Economies are frequently affected by natural disasters and both domestic and overseas financial crises. These events disrupt production and cause multiple other types of economic losses, including negative impacts on the banking system. Understanding the transmission mechanism that causes various negative second-order post-catastrophe effects is crucial if policymakers are to develop more efficient recovery strategies. In this work, we introduce a credit-based adaptive regional input-output (ARIO) model to analyse the effects of disasters and crises on the supply chain and bank-firm credit networks. Using real Japanese networks and the exogenous shocks of the 2008 Lehman Brothers bankruptcy and the Great East Japan Earthquake (March 11, 2011), this paper aims to depict how these negative shocks propagate through the supply chain and affect the banking system. The credit-based ARIO model is calibrated using Latin hypercube sampling and the design of experiments procedure to reproduce the short-term (one-year) dynamics of the Japanese industrial production index after the 2008 Lehman Brothers bankruptcy and the 2011 Great East Japan earthquake. Then, through simulation experiments, we identify the chemical and petroleum manufacturing and transport sectors as the most vulnerable Japanese industrial sectors. Finally, the case of the 2011 Great East Japan Earthquake is simulated for Japanese prefectures to understand differences among regions in terms of globally engendered indirect economic losses. Tokyo and Osaka prefectures are the most vulnerable locations because they hold greater concentrations of the above-mentioned vulnerable industrial sectors.

This study examines how research collaboration of firms affects the quality of their innovation outcomes using comprehensive patent data for firms in the world from 1991 to 2010. Identifying research collaboration by co-patenting relationships, we find that research collaboration with other firms, particularly with foreign firms, leads to substantial improvement in innovation quality. We also observe a positive effect of the brokerage in the global network, especially for firms with international collaboration links. These results are applicable to the effect on the quality of innovation achieved individually without any collaboration. Therefore, our findings emphasize the importance of links with a variety of partners, particularly with foreign partners to improve innovation performance. Finally, we find that the collaboration effect is larger in the 2000s than in the 1990s and varies depending on firm size and across countries.

This study investigates the localization of collaboration in knowledge creation by using data on Japanese patent applications. Applying distance-based methods, we obtained the following results. First, collaborations are significantly localized at the 5% level with a localization range of approximately 100km. Second, the localization of collaboration is observed in most technologies. Third, the extent of localization was stable from 1986 to 2005 despite extensive developments in information and communications technology that facilitate communication between remote organizations. Fourth, the extent of localization is substantially greater in inter-firm collaborations than in intra-firm collaborations. Furthermore, in inter-firm collaborations, the extent of localization is greater in collaborations with small firms. This result suggests that geographic proximity mitigates the firm-border effects on collaborations, especially for small firms.

This paper studies the structure of the Japanese production network, which includes one million firms and five million supplier-customer links. This study finds that this network forms a tightly-knit structure with a core giant strongly connected component (GSCC) surrounded by IN and OUT components constituting two half-shells of the GSCC, which we call awalnut structure because of its shape. The hierarchical structure of the communities is studied by the Infomap method, and most of the irreducible communities are found to be at the second level. The composition of some of the major communities, including overexpressions regarding their industrial or regional nature, and the connections that exist between the communities are studied in detail. The findings obtained here cause us to question the validity and accuracy of using the conventional input-output analysis, which is expected to be useful when firms in the same sectors are highly connected to each other.