Table 1. Definitions of key variables and description of measurement methods.

Variant	Variable name	Variant	Description of calculations
Implicit Variable	SA index	SA	Drawing on Sun’s study(2019), please see the text for the equation
Independent Variable	Director’s information technology experience	DTB	Ratio of directors with IT background to total number of board members
	Directors’ information technology experience Classification	DTC	Directors with information technology experience (denoted by "1") Directors without information technology experience (denoted by "0")
Intermediary Variant	Media coverage of sentimental value	REV	Media coverage in the year prior to the public offering computes the word vector, the sum of the positive and negative sentiment values
Containment Variant	Year of establishment	FT	Time from limited liability company formation to listing in years
	return on net assets	ROE	Ratio of net profit to total assets for the year preceding the initial public offering of the enterprise
	gearing	DAR	Ratio of corporate liabilities to total assets
	registered capital	RC	Registered capital in the public transfer prospectus of the enterprise
Clusters Variant	Grouping of independent directors	IDG	Whether the percentage of independent directors is higher than its sample median, in two groups