| Category | Code | Definition | |
| Explained Variable | Fee | Audit fee, measured by the natural logarithm of the company’s audit fee | |
| Explaining Variables | Spe | Industry Specialization, measured by the cumulative number of signature of auditor i in industry k before year t | |
| Gender | Gender, is 1 for male auditor and 0 otherwise | ||
| Age | Auditor’s age | ||
| Edubg | Auditor’s education background, is 1 for bachelor degree or above, and 0 otherwise | ||
| Partner | Whether the auditor is partner, is 1 for partner, and 0 otherwise | ||
| Exp | Number of audit year, measured by the time of year i deducting the year of registration of CPA | ||
| Busyness | Auditor busyness, measured by the total audit tasks of auditor i in year t | ||
| Control Variables | Firm’s Characteristics | Opinion | Audit Opinion, is 1 for modified audit opinion, and 0 otherwise |
| Big 10 | Top 10 firms in year i, is 1 for the company which is audited by “big 10”, and 0 otherwise | ||
| Switch | Whether switch the firm, is 1 if the company switch the firm, and 0 otherwise | ||
| Auditee’s Characteristics | Em | Earnings management, extraordinary item/ absolute value of profit for the year | |
| Complexity | Complexity of economic business, the sum of inventory and account receivables/total asset | ||
| Lev | Solvency, asset-liability ratio | ||
| Grow | Development capacity, revenue growth rate | ||
| Size | Asset size, natural logarithm of total assets at year end | ||
| Punish | Governance risk, is 1 if the company is punished by regulators, and 0 otherwise | ||
| Loss | Financial risk, iss 1 if profit for the year is positive, and 0 otherwise | ||