Variable	Variable definitions
Explained variable
Inst	On June 30, 2008, the shareholding ratio of institutional investors in the company
Explanatory variables (characteristic variables of critical audit matters)
Num_cam	The number of critical audit matters
Freq_num	The average value of proportion of the numerical value contained in each critical audit matter (the total value of each proportions divided by the number of critical audit matters of the company)
Freq_per	The average value of proportion of the percentage value contained in each critical audit matter (the total value of each proportions divided by the number of critical audit matters of the company)
Freq_spe	Specific critical audit matters, the average value of proportion of the company’s specific critical audit matters to the company’s number of critical audit matters (define the company’s specific critical audit matters as critical audit matters whose probability of occurrence is less than 50%)
The Form	Format of disclosure of critical audit matters: define company with tabular as 1, textual narratives as 0.
Control variable
$I n s t_{t - 1}$	On June 30, 2017, institutional investors in the company’s shareholding
(1) company characteristic variables (9)
Lev	The company’s asset-liability ratio
Eps	Basic earnings per share of the company
Ocfps	Operating cash flow per share of the company
The Size	The logarithm of a company’s total assets
Price,	Year-end closing price
Divi	Whether the company pays cash dividends at the end of the year: define company with dividend as 1, otherwise as 0.
The State	Define the property right of the company is 1 for state-owned company and 0 for non-state-owned company
Opi	Audit opinion. Define a clean report as 1, otherwise as 0.
Big 4	Accounting firm. Define the company audited by international big 4 accounting firm as 1, otherwise as 0.
(2) industry control variables (21)
Sic 2	According to the industry classification of China securities regulatory commission in 2012, the industry types are controlled