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. 2024 Jun 11;19(6):e0304560. doi: 10.1371/journal.pone.0304560

Table 9. The effect of academic freedom (AF) on innovation output (forward citations) with the sample split according to the total number of forward citations per country.

Model (1) (2) (3) (4)
Sample Top 25 countries Top 50 countries Countries not in top 50 Excluding countries with 0 citations
Dependent variable Forward citationst+5 (ln) Forward citationst+5 (ln) Forward citationst+5 (ln) Forward citationst+5 (ln)
Statistic Coeff. (SE) Coeff. (SE). Coeff. (SE) Coeff. (SE)
Independent varibale
    AF (z) 0.399 (0.063)*** 0.362 (0.042)*** -0.001 (0.002) 0.395 (0.032)***
Controls
    Patent applications (ln) Yes Yes Yes Yes
    Year/country dummies Yes Yes Yes Yes
Countries (observations) 25 (2,664) 51 (4,943) 106 (6,978) 73 (6,576)
R2 (R2 adjusted) 0.756 (0.743) 0.681 (0.670) 0.165 (0.138) 0.653 (0.643)

Notes: The estimates are obtained from pooled OLS regressions. All variables are described in Table 1. Robust standard errors in parentheses.

* p < 0.10

** p < 0.05

*** p < 0.01.