| Variable Type | Variable Name | Symbol | Variable Definition | Variable Type |
| Dependent variable | Internal pay gap | Gap | Refer to the relevant study by Zhou Quanxiong et al. | Dependent variable |
| Independent variable | Enterprise digitalization | ED | Drawing on the research ideas of Wu Fei et al. [16] | Independent variable |
| Mediating variables | Absorptive capacity | AC | Ratio of R&D expenditure to operating revenue * 100 | Mediating variables |
| Control variables | Enterprise Age | List Age | ln(current year − year of launch + 1) | Control variables |
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| Enterprise size | Size | Natural logarithm of total assets |
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| Nature of ownership | SOE | Dummy variables: 1 = state-owned, 0 = other |
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| Concentration of ownership | Top1 | Number of shares held by the largest shareholder/total number of shares |
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