# New Possibilities of Using DEMATEL and ERPN in the New PFMEA Hybrid Model
## 3 Results and Discussion
### Theoretical Analysis of the Proposed Models  
In our research, we started with a real-world problem that often occurs when PFMEA is used in practice. PFMEA reaches its limits if we identify many failure modes with the same RPN. This was evident in one of the proposals for solving this problem. This was the classical continuation analysis of PFMEA (conventional PFMEA). For time, organizational reasons, and economic reasons, it is not possible to apply the measures and solve all the problems at once. It is therefore very important to establish a clear prioritization for the proposal of measures. We used the conventional PFMEA as a benchmark for comparison with other proposals, even though it was clear that the PFMEA would be ineffective and unable to reduce the monitored criteria. This was also confirmed. Many authors have used the DEMATEL model to overcome these limits [21; 31; 32; 33; 35; 36; 37; 38; 39; 43; 44]. This was also demonstrated in our research. Moreover, we confirmed these results by monitoring the proposed criteria, which we were able to reduce. Among the requirements of manufacturing organizations, the main aim is to reduce the number of defective products. The DEMATEL model results in a digraph that gives us \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Failure Mode**} & \multirow{2}{*}{**IFC [€]**} & \multicolumn{3}{c}{**PFMEA**} & \multicolumn{2}{c}{**PFMEA**} & \multirow{2}{*}{**DEMATEL**} & \multirow{2}{*}{**ERPN**} \\  & & & & **Initial State** & & & **Conventional** & & & \\  & & & **n\({}_{\mathbf{n}}\)** & _FC [€]_ & **n\({}_{\mathbf{n}}\)** & _FC [€]_ & **n\({}_{\mathbf{n}}\)** & _FC [€]_ & **n\({}_{\mathbf{n}}\)** & _FC [€]_ \\ \hline FM2 & 3.55 & 8.61 & 40 & 486.4 & 29 & 352.64 & 14 & 170.24 & 17 & 206.72 \\ FM3 & 0.31 & 0.31 & 42 & 26.04 & 29 & 17.98 & 12 & 7.44 & 29 & 17.98 \\ FM4 & 0.2 & 0.2 & 40 & 16 & 35 & 14 & 29 & 11.6 & 32 & 12.8 \\ FM5 & 6.79 & 8.86 & 44 & 688.6 & 38 & 594.7 & 14 & 219.1 & 31 & 485.15 \\ FM6 & 0.15 & 3.83 & 44 & 175.12 & 43 & 171.14 & 35 & 139.3 & 37 & 147.26 \\ FM7 & 0.1 & 0.11 & 42 & 8.82 & 44 & 9.24 & 38 & 7.98 & 39 & 8.19 \\ FM8 & 0.53 & 2.93 & 44 & 152.24 & 16 & 55.36 & 31 & 107.26 & 30 & 103.8 \\ FM9 & 0.2 & 3.1 & 42 & 138.6 & 23 & 75.9 & 17 & 56.1 & 31 & 102.3 \\ FM10 & 2.31 & 4.34 & 42 & 279.3 & 28 & 186.2 & 34 & 226.1 & 29 & 192.85 \\ FM11 & 0.68 & 6.49 & 40 & 286.8 & 18 & 129.06 & 29 & 207.93 & 15 & 107.55 \\ FM12 & 2.14 & 7.9 & 42 & 421.68 & 24 & 240.96 & 30 & 301.2 & 18 & 180.72 \\ \hline \(\Sigma\) & & & 462 & 2679.6 & 327 & 1847.18 & 283 & 1454.25 & 308 & 1565.32 \\ \hline \hline \end{tabular}
\end{table} 
Table 14: The economic evaluation of models. information about the interaction between failure modes and categorizes the modes into influencing and influenced modes. We have used these results to estimate whether and how each of the proposed models can reduce the monitored criteria. In doing so, we also considered the strength of the interaction between the failure modes that were obtained from the experts' evaluations and is presented in Table 3. The results showed that our estimation was correct. It should be emphasized that DEMATEL is highly dependent on the input values. This requires quality experts knowledgeable about the system being evaluated. If the input data are not exact, the DEMATEL results will be misleading and the estimation of the models functionality will be incorrect. Based on the research by [PERSON] et al. [8], we constructed the ERPN model. We confirmed the results of that research because we were able to determine the prioritization of failure modes. In our study, we again confirmed these results by validating them in practice. Subsequently, we proposed a model for the economic evaluation of the benefit of the models, where we used internal and external costs (they are created as an economic effect of the failure modes and are identified in the ERPN model). These data were the basis for the determination of the ERPN.