4.2.5. Control Variables

In order to reduce the interference of factors other than independent variables and dependent variables in this study, several control variables are included in the analysis drawing on the research of Yang et al. (2018, 2019) [69], Fang et al. (2016) [77], Xiao et al. (2019) [78], and Zhang et al. (2022) [79].

(1) Proportion of technical employees: Human resources are the main force in technological innovation. It is crucial to have a certain number of technical personnel for high-quality innovation. (2) Employee proportion with a bachelor's degree or above: it affects the quality of enterprise human capital, and controlling this variable can avoid the interference caused by the difference of human capital among enterprises. (3) TMT average age: TMT average age reflects the risk tendency of the team members to make decisions. (4) Enterprise size: It may affect the extent of resources that firms commit for capabilities such as innovation. The resources will influence the speed and outcome of strategic decisions made by the TMT. (5) The TMT size: it affects the process and results of internal collaboration among team members [1]. (6) R&D investment: it is an important reflection of its innovation capability and innovation quality. (7) Enterprise capital structure: Capital structure is the result of enterprise financing. It determines the ownership of the property of the enterprise and also stipulates the rights and interests of different investment subjects and the risks borne by them.

Table 1 shows the definitions and descriptions of all variables.


**Table 1.** Variable definition and description.
