## 4 Empirical Analysis of the Uncertainty Index System
### Construction of an Uncertainty Index System  
The PEST model is an analytical model that helps companies study the external environment. In this paper, the PEST model is improved to make it suitable for the study of uncertainty in the application of digital technology. It generally corresponds to the four main categories of political, economic, social and technological [53]. In this paper, we draw on the classification of the PEST model to classify the uncertainty of the new generation of digital technologies. According to the identification results of the LDA theme model, the uncertainties with weak influence on digital technology application were eliminated and, finally, 13 main uncertainties were selected and classified according to the nature of uncertainty factors, which were divided into five aspects: policy, industry, personnel, economy and law. The index system is shown in Table 3.  
Policy. In recent years, the application of new generation digital technologies in the construction industry, such as the Internet of Things (IoT), Building Information Modelling (BIM) and big data, has greatly improved the productivity of the construction industry. The adoption of new-generation technologies by companies should be preceded by the adoption of technologies at the national level [54]. After evaluating the advantages of new-generation digital technology, if the state believes that the new technology can bring cost reduction and efficiency improvement to the construction industry under the guidance of relevant national policies, at the enterprise level, construction enterprises selectively introduce the new-generation digital technology according to the guidance of national policies, in order to achieve the purpose of enterprise cost reduction and efficiency improvement. Therefore, the formulation, implementation and supervision of policies play important roles in guiding and ensuring the application of new-generation digital technologies in the construction industry. Industry. The mode of production organisation of the industry affects the development of new technologies to a certain extent; the organisation and process of China's construction industry is basically divided, resulting in the overall efficiency of the industry being not high, and this inefficiency has been tolerated by the industry and the market for a long time, resulting in a lack of motivation to transform most of the construction enterprises [5]. Therefore, reform of the existing mechanisms of the construction industry and the transformation of the organisational and business methods of construction production have become the key to the application of the new generation of digital technologies. In addition, a new type of technical means can be easy to get started and the rapid development of the key is its good applicability; therefore, the new technology related to the degree of perfection of \begin{table}
\begin{tabular}{c c c} \hline \hline
**Hierarchical Division** & \multicolumn{2}{c}{**Uncertainty Indicator System**} \\ \hline \multirow{2}{*}{Policy A} & A\({}_{1}\) & \multirow{2}{*}{Perfection of the policy protection system} \\  & A\({}_{2}\) & \\  & A\({}_{3}\) & \\ \hline \multirow{3}{*}{Industry B} & B\({}_{1}\) & \multirow{3}{*}{Perfection of technical standards and guidelines} \\  & B\({}_{2}\) & \\ \cline{1-1}  & B\({}_{3}\) & \\ \hline \multirow{3}{*}{Personnel C} & C\({}_{1}\) & Number of professional technicians \\ \cline{1-1}  & C\({}_{2}\) & \multirow{3}{*}{Acceptance of digital technology} \\ \cline{1-1}  & C\({}_{3}\) & \\ \hline \multirow{3}{*}{Econom. Personnel D} & D\({}_{1}\) & Cycle of return on investment for digital technology \\ \cline{1-1}  & D\({}_{2}\) & \multirow{3}{*}{Software and hardware configuration upgrade costs} \\ \hline \multirow{2}{*}{Legal Aspect E} & E\({}_{1}\) & \multirow{2}{*}{Perfection of the legal system of intellectual property protection} \\ \cline{1-1}  & E\({}_{2}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Uncertainty Indicator System.