Table 1.
Variables and definitions.
| Types of variables | Variable name | Symbol | Variable definition |
|---|---|---|---|
| Explained variable | Number of green patent applications | GP | Number of green applications filed that year |
| Number of green invention applications filed | GI | Number of green inventions filed that year | |
| Number of green utility models | GUMI | Number of green utility models applied for that year | |
| Proportion of green inventions | PGI | Green inventions as a percentage of total patents granted annually in the district | |
| Proportion of green utility models | PGUMI | Green utility models accounted for the total number of utility models obtained in the region | |
| Explanatory variables | Whether to process effects | DDD | Whether to implement carbon trading policy, the interaction item of individual time point industry |
| Individual variables | Whether the individual is processed | treat | Yes, take 1; No, take 0 |
| Ticker symbol | stkcd | Ticker symbol | |
| Time point variable | Whether to process time | period | Yes, take 1; No, take 0 |
| A given year | year | Year | |
| Industry variables | Whether to deal with industry | group | Yes, take 1; No, take 0 |
| Industry | Industry | Industry code | |
| Control variables | Asset size | LnAssets | Natural log of total annual assets |
| Net profit rate on total assets | ROA | Net profit/average balance of total assets | |
| Tobin Q value | Q | (Market value of outstanding shares + number of non-tradable shares x net assets per share + book value of liabilities)/total assets | |
| Asset-liability ratio | Leverage | Total year-end liabilities divided by total year-end assets | |
| Operating growth rate | Growth | Current Year operating income/Previous year operating income − 1 | |
| Cash flow ratio | Cash | Net cash flow from operating activities divided by total assets | |
| Return on equity | ROE | Net profit/average balance of shareholders’ equity | |
| Turnover of total assets | ATO | Operating income/average total assets | |
| Book-to-market ratio | BM | Book value/total market value | |
| Number of years established | LnAge | ln(year of the year - year of incorporation + 1) | |
| Corporate ownership | SOE | The value is 1 for state-controlled enterprises and 0 for others | |
| Mediating variables | Vendor concentration | SI | Top five supplier purchases as a percentage of total annual purchases |
| Customer concentration | CI | Ratio of top five customer sales to total annual sales |