3.2.4. Control Variables

We controlled for the following variables at the firm level: firm size (total assets), firm age (years since the firm's founding), Top1 (largest shareholder), ROA (return on asset to proxy for firm performance), and Lev (asset–liability ratio). To control for other important characteristics of boards and CEOs, we included the following variables in our models: Board (natural logarithm of the number of directors); Inde (independent director), which denoted the proportion of independent directors on the board; and Dualiy (CEO and chairman duality), which indicated the overlap of the CEO and Chairman of the board. In addition, this paper controlled the industry effects (Industry) and year effects (Year) on firms green innovation, respectively.

Based on this, the descriptions of the variables are summarized in Table 2.


**Table 2.** The descriptions of the variables.
