## 5 Analysis of Factors Influencing the Digital Service Trade Network of RCEP Member Countries
### QAP Regression Analysis
#### 5.1.2 Variable Selection Instructions  
After comprehensive consideration, the following influencing factor indicators are selected, as shown in Table 8. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Ranking** & **2006** & **2021** \\ \hline
1 & Singapore & Singapore \\
2 & Japan & Japan \\
3 & Malaysia & China \\
4 & Thailand & Thailand \\
5 & China & Malaysia \\
6 & Australia & Australia \\
7 & South Korea & South Korea \\
8 & Indonesia & Indonesia \\
9 & Philippines & Philippines \\
10 & Laos & Laos \\
11 & New Zealand & New Zealand \\
12 & Brunei & Brunei \\
13 & Cambodia & Cambodia \\
14 & Myanmar & Myanmar \\
15 & Vietnam & Vietnam \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Ranking of Intermediate Centrality Index of Overall Digital Services Trade Network of RCEP Member Countries in 2006 and 2021. Explanated Variable DSTcj is a comprehensive digital service trade and segmented industries trade network matrix constructed based on RCEP member countries' digital service trade data sourced from the OECD database. Explanatory Variable  
Difference in per capita GDP (GDPGj): Per capita GDP is usually used to evaluate the overall economic health of a country and can be used to measure its level of economic development. The greater the difference in economic development between two countries, the less likely it is to engage in bilateral digital service trade. Therefore, this study represents the absolute value of the difference in per capita GDP between the two countries using a matrix sourced from the World Bank database. Differences in the level of digital infrastructure (INFcj): The level of digital infrastructure measures the development level of a country or region in digital technology and information and communication technology. Referring to the research of [PERSON] [33] and other scholars, the development level of digital infrastructure is reflected by the comprehensive level of four indicators, namely the number of fixed telephone users, the number of fixed broadband users, the number of mobile cellular users, and the number of secure Internet servers. The smaller the difference in the development level of digital infrastructure between the two countries, the easier it is to carry out bilateral digital service trade. In this study, the absolute value of the difference in the level of digital infrastructure between the two countries is expressed by a matrix, and the data is taken from the World Bank database. Institutional distance (SYScj): The institutional distance between different countries or regions reflects the institutional gap, which not only leads to the existence of trade barriers but also increases trade costs. Drawing on [PERSON]'s [34] selection of indicator factors, six governance indicators, including discourse power and accountability, political stability and absence of terrorism, regulatory quality, government efficiency, corruption control, and the rule of law, are used to measure institutional distance. The specific measurement method is shown in Equation (2). The greater the institutional distance between two countries, the more obvious the institutional gap and the less likely it is to engage in bilateral digital service trade. Therefore, this study represents the institutional distance between two countries using a matrix with data sourced from the World Bank database. \[\text{SYS}\text{q}=\text{1}\text{S}_{\text{ct}}-\text{s}\text{S}_{\text{gt}} \text{1}/(\text{1}\max\text{S}_{\text{ct}}-\text{min}\text{S}_{\text{gt}} \text{1}) \tag{2}\]  
Among them, SYScj represents the institutional distance between country c and country j, _Sct_ represents the governance index value of country c in the t-th year, and _Sjt_ represents