# Compilation of a City-Level & Four-Digit Industry Code MRIO Table Based on Firm-Level Data
## 1 Introduction  
Input-output tables with their extension inter-country input-output (ICIO) tables or multi-region input-output (MRIO) tables have been widely used in research on relationships between consuming and producing sectors, such as global value chains (GVC), international production networks and environmental analyses [1, 2]. Due to statistical and methodological limitations, including monetary price valuation, sector classification or aggregation, and uncertainties and absences in trade statistics, available input-output (IO) databases are limited. Besides the input-output table at the country level, several well-known and always being updated global MRIO databases are the Global Trade Analysis Project MRIO table (GTAP-MRIOT) [2], the World Input-Output Database (WIOD) [3], EXIOBASE [4], and Eora [5]. The existing literature has applied these databases extensively for various international comparisons. For example, [PERSON] et al. [6] analyzed the spatial differences in energy intensity among G20 countries based on the WIOD and revealed its driving factors by employing multiplicative structural decomposition analysis. In addition, subnational, domestic regional IO databases have been constructed for some countries, such as Australia (e.g., [7]), Spain (e.g., [8]), Germany (e.g., [9]), and China (e.g., [10]). Similarly, they are utilized for a variety of purposes (e.g., [11]). Today's global intertwined situation is characterized by the multi-polarization of manufacturing centers where GVC is extendedmainly in a regional form. That is, not only is the country an important participant in joining the GVC, but also domestic regions as intermediate products or service providers join the GVC directly or indirectly [12]. While many MRIO tables exist in different countries, very few tables include more subdivided regions and sectors. For example, the detailed national benchmark IO tables in the U.S. (United States) contain relationships only for the subdivided 405 industries and do not show input-output relationships between regions. The yearly input-output accounts data published by BEA (Bureau of Economic Analysis) contains 71 industries and 52 regions (50 states, the District of Columbia, and Puerto Rico). Scholars have also compiled more disaggregated tables for various research purposes. However, almost no MRIO table covers a large number of cities with more disaggregated sectors in countries, especially those with advanced urbanization and specialization. Therefore, this paper uses China as a case study to present our approach of compiling an MRIO table with the most disaggregated level of region and sector. China is a good example because processing trade is the main way of embedding the global value chain, and domestic regional trade accounts for a large percentage. As a result, the degree of correlation between China's economy and the world economy is not only reflected in the scale of trade but also in the changes in the country's industrial and economic structure, which can be reflected by MRIO. Moreover, in recent years, China's intermediate product imports have shown a continuous decline, and intermediate products have been transferred to the domestic market. This indicates an inward trend in GVC [13]. The COVID-19 epidemic has exacerbated the trend of reverse globalization and challenged the current domestic value chain [14]. A focus on the general situation at the regional scale in China indicates the contradictory phenomenon of the high level of overall national growth versus unbalanced regional development. A within-nation comparison reflects remarkable regional policies, strategies and industrial structure. Therefore, it is necessary to understand the economic interdependence among different regions in China through MRIO. Current related studies about China are mostly based on WIOD, or China's 31 provinces and 42 sector IO models. The National Bureau of Statistics of China (NBS) has compiled national input-output tables every five years since 1987.