## 5 Results
### PSM Results and Discussions
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Cooperation**} & \multirow{2}{*}{**CO1**} & \multirow{2}{*}{**CO2**} & \multirow{2}{*}{**CO31**} & \multirow{2}{*}{**CO32**} & \multirow{2}{*}{**CO4**} & \multirow{2}{*}{**CO5**} & \multirow{2}{*}{**CO6**} & \multirow{2}{*}{**CO7**} & \multirow{2}{*}{**COA**} & \multirow{2}{*}{**COB**} & \multirow{2}{*}{**COC**} & \multirow{2}{*}{**COD**} & \multirow{2}{*}{**COE**} \\ \hline NN & (0.080) * & 0.042 & (0.123 ** & 0.074 & 0.079 & 0.060 & 0.082 & 0.064 ** & 0.060 & 0.109 & 0.020 & 0.135 \\  & (1.51) & (1.16) & (2.63) & (1.25) & (1.19) & (1.52) & (1.24) & (1.22) & (2.07) & (1.37) & (1.07) & (1.27) \\
3 NN & \(-\)0.005 & 0.034 & (0.090 ** & 0.040 & 0.033 & 0.070 & 0.089 * & 0.079 * & 0.076 & 0.157 & 0.090 \\  & \(-\)0.12 & (1.12) & (2.34) & (1.08) & (0.77) & (0.78) & (0.81) & (1.29) & (1.88) & (2.19) & (0.89) & (1.49) & (0.99) \\  & \(-\)0.013 & 0.026 & (0.064 ** & 0.110 & 0.036 & 0.048 & 0.036 & 0.061 & 0.045 ** & 0.087 ** & 0.063 & 0.162 & 0.084 \\  & \(-\)0.31 & (0.89) & (2.09) & (1.26) & (0.72) & (1.17) & (0.93) & (1.14) & (1.79) & (2.56) & (0.77) & (1.56) & (0.94) \\ Kernel & \(-\)0.008 & 0.029 & (0.074 ** & 0.137 & 0.031 & 0.045 & 0.040 & 0.045 & 0.037 & 0.071 & 0.091 & 0.016 & 0.102 \\  & \(-\)0.21 & (0.21) & (0.25) & (1.77) & (0.65) & (1.18) & (1.10) & (0.88) & (1.59) & (2.26) & (1.22) & (1.06) & (1.22) \\ \hline Obs. & 864 & 1897 & 1139 & 329 & 613 & 811 & 956 & 515 & 2514 & 1380 & 235 & 158 & 225 \\ Caliper & 0.015 & 0.015 & 0.017 & 0.022 & 0.019 & 0.017 & 0.019 & 0.020 & 0.016 & 0.016 & 0.018 & 0.022 & 0.021 \\ \hline \multicolumn{10}{c}{**ATT and T-stat**} \\ \hline
**Nations** & **Bulgaria** & **Estonia** & **Greece** & **Cronia** & **Hungary** & **Latvia** & **Portugal** & **Romania** \\ \hline NN & 0.121 ** & 0.125 & 0.054 & 0.054 & \(-\)0.016 & 0.056 & 0.019 & \(-\)0.024 \\  & (3.20) & (1.31) & (1.05) & (0.94) & (\(-\)0.31) & (0.54) & (0.62) & (\(-\)0.26) \\
3 NN & 0.100* & 0.068 & 0.035 & 0.049 & 0.002 & 0.146 * & 0.037 & \(-\)0.024 \\  & (3.09) & (0.82) & (0.84) & (0.99) & (0.04) & (1.65) & (1.42) & (\(-\)0.28) \\
5 NN & 0.097 ** & 0.052 & 0.044 & 0.045 & 0.019 & 0.135 & 0.031 & \(-\)0.053 \\  & (3.13) & (0.65) & (1.10) & (0.95) & (0.46) & (1.58) & (1.25) & (\(-\)0.64) \\ Kernel & 0.107 ** & 0.016 & 0.059 & 0.058 & 0.015 & 0.127 & 0.031 & \(-\)0.023 \\  & (3.81) & (0.21) & (1.58) & (1.31) & (0.41) & (1.60) & (1.36) & (\(-\)0.31) \\ \hline Obs. & 2436 & 301 & 1062 & 776 & 1204 & 296 & 3204 & 419 \\ Caliper & 0.015 & 0.021 & 0.019 & 0.021 & 0.018 & 0.021 & 0.015 & 0.019 \\ \hline \end{tabular} Source: author’s elaboration. ATT is the average treatment effect on the treated. T-stat is shown in the parentheses, as are the t-statistic of the difference \(t\)-test of the treated group and the matched control group. ** \(p<\) 0.1, ** \(p<\) 0.05, *** \(p<\) 0.01 if the t-statistic is located within (1.645, 1.960), (1.960, 2.576), and \(>\)2.576, respectively. Matching is conducted only within the common support. All individuals with the same proper \(p\)-score are selected if there are any. Caliper is 0.1 * std. dev. of the \(p\)-score. The results for other countries are omitted because of “no observations” and “insufficient observations”. Please refer to Table 2 for a detailed variable description.  
\end{table} 
Table 7: PSM results, perfectly matched cooperation and nation. The outcome is innovation with environmental benefits. introduce environmental innovation: mining and quarrying (30.0-40.0%), water and waste management (16.4-19.8%), cultural-related activities and information services (7.1-9.7%), financial service activities (16.2%, 25%), and professional, scientific, technical activities, and veterinary (12.9%).