The concept of a "global production network" is important for understanding a country's or a firm's economic competitiveness. A big firm, called a flagship, is likely to form a production network, which comprises of a lot of other related firms. The economic performance of a firm in the production network depends on the efficiency of the production network. So, it is necessary to survey the characteristics of a production network for us to fully understand how strong the economic power our certain industry or firm has. (The rest is omitted.)