## 5 Findings and Discussion
### Discrepancy of the Two Perspectives  
Discrepancy means there are some conflicts or changes between facts, figures, or claims. It represents different types of opinions that are associated with different cognition. The results reveal that social-technical sustainability is characterized by indicator discrepancy. As listed in Table 9, the \"bearing capacity of structure\" is a primary indicator of social-technical sustainability. This indicator acknowledges the advantages of high carrying capacity of steel structures from the perspective of technical sustainability. It also underlines the value of structural safety for end-users, which may be considered a proxy for social sustainability. This finding is consistent with [PERSON] et al.'s [51] views that structural bearing capacity is the basis of comfort for users. It also sheds new light on steel structures' social-technical performance. In effect, this indicator's dual role embodies the rationale of sustainable construction by giving a broader definition of social sustainability, namely social-technical sustainability.  
The results indicate that designers and constructors are prone to bias towards some indicators, including \"structural constructability\" and \"weldability of steel\". The reason is that constructors are accustomed to advanced technologies, construction plans, and construction operability in the construction process. However, designers might not be inclined to them due to the scope of services [52]. On the contrary, designers may purport to those indicators such as \"vulnerability of structure\" and \"living comfort of steel structure\" differently from what constructors do. Therefore, if designers fail to work on these indicators from design-construction integration, it will make inefficiency in the construction process and give rise to construction accidents.  
The discrepancy of sustainability indicators also applies to the dimension of greenness. Figure 5 shows the differences between designers and constructors in evaluating the greenness indicators. Constructors hold that the \"utilization ratio of underground space\", \"construction land area\" and \"construction electricity consumption\" are critical,whereas designers insist that such indicators make no sense. This is partial, provided that construction engineers, who control this type of indicator, represent construction enterprises' interests instead of design institutes. In this study, it is suggested that design enterprises should more consider such indicators in the project implementation process. As many countries have not enforced greenness specifications for steel structures, assessing environmental sustainability for steel structure projects might be challenging. A typical example is that Israeli attaches importance to the indicators of \"evaluator impression\" and \"solid waste\" in the building performance assessment system [53]. Jordan emphasizes the efficient use of environmental resources and deems the \"soil protection\" and \"plant coverage\" indicators to be crucial [54]. At a county level, it is understandable that the greenness indicators in China's urbanization context differ from that in other counties such as Israel and Jordan.