Service inputs before and after the manufacturing process are important components in the production process. Moreover, this service input largely determines the value-added of final goods. It is generally said that service input, not the manufacturing process, produces the largest amount of value-added in final goods.
This is known as the "smile curve," that is, the relationship between the degree of value-added and production process is a U-shaped curve. GVCs made full use of comparative advantages by segmenting each production process. As a result of the development of GVCs, a service process other than a manufacturing process stays in developed countries, while the manufacturing process moved into Asian countries.