| Variable type | Variable name | Definition of major variables |
| Explained variables | NCSKEW | Negative skewness of share’ s return rate in the year of t. |
| Crash | If there is any stock crash of a firm in the year of t. | |
| Explaining variable | R&D | Tthenapierian logarithm is gotten by adding 1 to firm’s expenditure on R&D. |
| Control variables | RturnSd | The excess turnover rate of share I in the year of t. |
| RetFirmAvg | The annual average of specific weekly return rate of share I in the year of t. | |
| Sigma | The annual standard deviation of specific weekly return rate of share I in the year of t. | |
| Size | The size of a firm, napierian logarithm of total assets. | |
| Lev | Asset-liability ratio. | |
| BM | The proportion of a firm’s book value to market value. | |
| ROA | Return on total assets which is gotten by dividing net profit by the total assets at year end. | |
| AbsDa | The accrued profit calculated with modified Jones model. |