| Variable | Definition |
| Inv_effi | Residual calculated from the Richardson (2006) [8] model. If the residual > 0, it means the firm over-invests; if the residual < 0, it means the firm under-invests; if the residual = 0, it means the firm reaches it optimal investment level |
| Reform | Dummy variable = 1 if affected by the investment system reform |
| Time | Dummy variable = 1 after the investment system reform |
| Size | Natural log of the total asset |
| Lev | Ratio of total liability to total asset |
| Cash | Cash and cash equivalents |