Does Tax Uncertainty Affect Firm Innovation Speed?

China implemented a new corporate income tax system in 2008, and to ensure the consistency of the index and avoid the interference of noise, we select all A-share firms listed on the Shanghai and Shenzhen Stock Exchanges from 2008 to 2020 for the initial sample. We obtain the data from the CSMAR and Wind databases. In this study, we exclude (1) firms with a negative denominator in the effective tax rate calculation; (2) firms whose actual tax rates are less than 0 or greater than 1; (3) Special treatment firms and firms from the financial industry to avoid the influence of special firms and special industries; and (4) those with missing values for the required data.