1. The ratio of value-added and the ratio of surplus-operated can only be compared meaningfully among industries with similar characteristics.
2. The intermediate inputs of service industry mainly consist of operation expenses, for example, fees of rents, utilities, and communication. In contrast, the other industry requires mass materials and supplies to produce. This is the reason why the ratio of intermediate inputs in the other industry is higher than service industry. Similarly, the ratio of value-added in service industry is higher than the other industry. Therefore, it is meaningless to compare with different characters of the industry.