## 5 Results
### PSM Results and Discussions
They possess greater competitive advantages in tenders than SMEs, especially when the government does not provide preference to SMEs [33]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Individual Innovations**} & \multicolumn{8}{c}{**ATT and T-stat**} \\  & **ECOINNO** & **ECOMINO** & **ECOMINO** & **ECOMINO** & **ECOMINO** & **ECOMINO** & **ECOMINO** \\ \hline NN & 0.057 *** & 0.006 & 0.020 & 0.018 & 0.012 & 0.013 & 0.045 *** \\  & (3.25) & (0.42) & (1.31) & (1.25) & (0.83) & (1.39) & (2.87) \\
3 NN & 0.053 *** & 0.004 & 0.005 & 0.003 & 0.018 & 0.011 & 0.037 *** \\  & (3.60) & (0.03) & (0.41) & (0.25) & (1.47) & (1.45) & (2.76) \\
5 NN & 0.049 *** & 0.004 & 0.008 & 0.006 & 0.018 & 0.014 * & 0.037 *** \\  & (3.47) & (0.34) & (0.64) & (0.49) & (1.55) & (1.88) & (2.90) \\ Kernel & 0.061 *** & 0.008 & 0.012 & 0.007 & 0.016 & 0.011 & 0.033 *** \\  & (4.65) & (0.73) & (1.09) & (0.67) & (1.51) & (1.60) & (2.75) \\ \hline Obs. & 9724 & 9754 & 9755 & 9756 & 9757 & 9754 & 9757 \\ Caliper & 0.016 & 0.016 & 0.016 & 0.016 & 0.016 & 0.016 & 0.016 \\ \hline \multicolumn{8}{c}{**ATT and T-stat**} \\  & \multicolumn{8}{c}{_ECOIMOP-end_} & \multicolumn{8}{c}{_ECOCAT_} \\  & \multicolumn{8}{c}{_ECOENU_} & \multicolumn{8}{c}{_ECOINS_} & \multicolumn{8}{c}{_ECOREM_} & \multicolumn{8}{c}{ECOEXT_} & \multicolumn{8}{c}{ECOPRD} & \multicolumn{8}{c}{ECOPRC} & \multicolumn{8}{c}{ECORG} & \multicolumn{8}{c}{ECOMKT} \\ \hline NN & 0.031 * & 0.054 *** & 0.034 * & 0.034 ** & 0.056 ** & 0.013 & 0.014 & 0.009 \\  & (2.14) & (3.93) & (2.43) & (2.45) & (2.27) & (0.53) & (0.62) & (0.50) \\
3 NN & 0.038 *** & 0.057 *** & 0.026 ** & 0.029 ** & 0.041 ** & 0.004 & 0.12 & 0.004 \\  & (3.14) & (4.97) & (2.20) & (2.47) & (1.96) & (0.17) & (0.61) & (0.28) \\
5 NN & 0.037 *** & 0.056 *** & 0.030 *** & 0.030 *** & 0.047 ** & \(-\)0.002 & 0.012 & 0.003 \\  & (3.17) & (5.06) & (2.60) & (2.70) & (2.35) & (\(-\)0.11) & (0.64) & (0.25) \\ Kernel & 0.042 *** & 0.054 *** & 0.033 *** & 0.033 *** & 0.034 * & \(-\)0.003 & 0.026 & 0.013 \\  & (3.90) & (5.23) & (3.14) & (3.17) & (1.82) & (\(-\)0.19) & (1.55) & (1.05) \\ \hline Obs. & 9757 & 9740 & 9737 & 9736 & 4811 & 4811 & 4812 & 4812 \\ Caliper & 0.016 & 0.016 & 0.016 & 0.016 & 0.017 & 0.017 & 0.017 & 0.017 \\ \hline \hline \end{tabular}  
* Source: authors’ elaboration. ATT is the average treatment effect on the treated. T-stat is 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.  
\end{table} 
Table 5: PSM results. Outcomes are individual eco-innovation with different environmental benefits. Table 7 demonstrates the PSM results when we match the cooperation or nation perfectly. Public procurement works on environmental innovation in enterprises cooperating with clients from the private sector (6.4-12.3%, \(p\leq\) 0.05), with partners from the same country (6.4%, \(p\leq\) 0.05, only in NN), and with partners from other European countries (7.1-8.7%, \(p\leq\) 0.05, 3 NN, SNN, and kernel). For the subgroups of nations, merely in Bulgaria, the public contract is estimated to be statistically significantly related to a company's decisions on eco-innovation (9.7-12.1%, \(p\leq\) 0.01). Table 8 implies the impact of a public contract on eco-innovation in each industrial sector. In the following five sectors, enterprises having public contracts are more likely to