Fig 1.
Number of NIPDAFs in China over the years since 2013.
Fig 2.
Impact mechanism of comprehensive intellectual property ability on firm productivity.
Table 1.
Description and measurement for the variables.
Table 2.
Descriptive statistics for the variables.
Fig 3.
Trend of firm productivity in 2011–2020.
Table 3.
Results of basic model regression.
Fig 4.
Parallel trend test.
Table 4.
Goodman-Bacon decomposition.
Fig 5.
Placebo test.
Fig 6.
Results of balance hypothesis test.
Fig 7.
Kernel density plot of propensity score values before and after PSM.
Table 5.
Results of PSM-DID and alternative indicators.
Table 6.
Results incorporating contemporaneous policies.
Table 7.
Results of mechanism analysis.
Table 8.
Results of heterogeneity analysis.