## 2 Materials and Methods
### Construction of Quality Risk Evaluation Indicator System for Assembled Building
#### 2.1.1 Identification of Quality Risk Factors for Assembled Building

Table 1: Quality risk evaluation indicators of the whole process of prefabricated buildings. The decision-making design phase U\({}_{1}\) contains four indicators, which are the deviation rates for key design parameters U\({}_{11}\), the amount of design team experience on relevant projects U\({}_{12}\), the number of design changes in the prefabricated components U\({}_{13}\), and the construction rework rate after meetings and handovers U\({}_{14}\). Excessive deviations or frequent changes in key design parameters can lead to construction delays and quality hazards, affecting the overall controllability of the project. An experienced design team can more effectively solve complex problems encountered during the design process, reduce errors and omissions during the design phase, and minimize the risk of rework. A high rework rate means that inadequate preliminary design briefings or inadequate reviews lead to deviations during construction, triggering safety hazards. The bidding and procurement phase U\({}_{2}\) contains three indicators which are, the number of enterprises participating in the tender U\({}_{21}\), the scoring of the suppliers' and the contractors' qualifications U\({}_{22}\), and the acceptance rate of purchased materials U\({}_{23}\). The greater the number of companies bidding, the more competitive the bidding will be and the more adequate the bidding will be, which will help in the selection of quality suppliers. The qualifications and reputation of suppliers or contractors may be directly affected by changes in policy or adjustments in regulatory requirements, which can have a knock-on effect on the quality risk of the project, and suppliers and contractors with high qualification scores will be able to ensure the quality of construction of the project. The acceptance rate of materials directly reflects the quality control of the procurement process, which is crucial to the stability and safety of subsequent construction. The production and transportation phase U\({}_{3}\) contains seven indicators which are, immature technical specifications for component production U\({}_{31}\), the raw material quality and supply chain stability U\({}_{32}\), the production equipment failure rate and utilization rate U\({}_{33}\), the average years of experience of the production staff U\({}_{34}\), the number of production meetings and the time for communication and feedback U\({}_{35}\), the transportation damage rate U\({}_{36}\), and the compliance rate of stacking protection and handling measures U\({}_{37}\). Immature technical specifications can directly lead to deviations in the production of components, affecting their consistency. Raw material quality and supply chain stability can vary significantly due to fluctuations in raw material prices or the risk of supply chain disruptions, which often result from dynamic changes in the external market environment, and poor raw material quality and supply chain delays can affect not only the timely supply of components, but also the construction schedule. Failure of production equipment and inexperienced personnel can increase uncertainty in the production process and affect the overall quality of the project. Production meetings and feedback mechanisms can help resolve production issues and reduce the risk of information asymmetry. The transportation damage rate and stacking protection, and the loading and unloading measures ensure the safety of components in the logistics process, preventing damage or quality degradation during transportation and storage. The U\({}_{4}\) indicator layer of the on-site assembly construction stage consists of four indicators, namely, the construction personnel training pass rate U\({}_{41}\), the assembly construction technology implementation compliance rate U\({}_{42}\), the unreasonable site plan U\({}_{43}\), and the acceptance pass rate U\({}_{44}\). The skill and training level of construction personnel directly affects the smooth running of the project.