## 2 Theoretical Background
### Comparative Analysis of Methods
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Reference** & **[PERSON]** & **[PERSON]** & & & & & & \\ and [PERSON], & & ✓ & 1 & & ✓ & ✓ & Periodic & Validation procedure \\
2013 [28] & & & & & & & & \\ \hline \hline ([PERSON], [PERSON], and [PERSON], 2018) [15] & & & 2 & ✓ & ✓ & & Dynamic & Delphi panel or questionnaire \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative analysis of methods. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Reference** & **Reference** & **Reference** & **Reference** & **Reference** & **Reference** & **Reference** & **Reference** & **Reference** \\ \hline ([PERSON], & & & & & & & & & \\ [PERSON], and & & ✓ & 1 & ✓ & ✓ & & & Dynamic & Strategic Alignment \\ [PERSON], 2020) [20] & & & & & & & & & \\ \hline ([PERSON], [PERSON], and & & & & & & & & \\ [PERSON], 2019) [17] & ✓ & & 2 & & ✓ & ✓ & & Periodic & Strategic alignment \\ \hline ([PERSON], [PERSON], & & & & & & & & \\ and [PERSON], & & ✓ & 3 & ✓ & ✓ & ✓ & Dynamic & Algorithmic procedure \\
2021) [22] & & & & & & & & & \\ \hline ([PERSON], [PERSON], & & & & & & & Static & Strategic alignment \\ and [PERSON], 2011) [2] & ✓ & & 3 & & ✓ & & & Static & Strategic alignment \\ \hline ([PERSON], [PERSON], and & & & & & & & & \\ [PERSON], 2003) [14] & ✓ & & 2 & ✓ & ✓ & & Static & Delphi panel or \\ \hline ([PERSON], [PERSON], & & & & & & & & \\ [PERSON], [PERSON], and & & & 2 & & & ✓ & Static & Strategic Alignment \\ [PERSON], 2019) [19] & & & & & & & & \\ \hline ([PERSON], [PERSON], & & & & & & & \\ [PERSON], and [PERSON], & & & 1 & ✓ & ✓ & ✓ & Dynamic & Delphi panel or \\
2017) [13] & ✓ & & 1 & ✓ & ✓ & ✓ & Dynamic & questionnaire \\ \hline ([PERSON], [PERSON], [PERSON], and & & & & & & & \\ [PERSON], 2016) [29] & ✓ & 3 & & & ✓ & Periodic & Validation procedure \\ \hline ([PERSON], [PERSON], and [PERSON], & 2021) [23] & ✓ & 2 & & ✓ & & Static & Algorithmic procedure \\ \hline ([PERSON], [PERSON], [PERSON], & & & & & & & \\ [PERSON], and [PERSON], & & & 3 & ✓ & ✓ & & Static & Delphi panel or \\
2014) [9] & & & & & & & & \\ \hline ([PERSON] and [PERSON], 2017) [7] & ✓ & 2 & & ✓ & ✓ & Static & Algorithmic procedure \\ \hline ([PERSON], [PERSON], & & & & & & & \\ [PERSON], and & & & & & & & \\ [PERSON], 2018) [5] & ✓ & 1 & ✓ & ✓ & Dynamic & Decision support \\ \hline ([PERSON] et al., & & & & & & & \\
2016) [27] & ✓ & 2 & & ✓ & ✓ & Static & Algorithmic procedure \\ \hline ([PERSON], [PERSON], and & & & & & & \\ [PERSON], 2000) [21] & ✓ & 1 & ✓ & ✓ & Static & Decision support \\ \hline ([PERSON], & & & & & & & \\
2021) [18] & ✓ & & 3 & ✓ & ✓ & Static & Strategic alignment \\ \hline ([PERSON], & & & & & & & \\
2017) [16] & ✓ & & 3 & ✓ & ✓ & Dynamic & PMM \\ \hline ([PERSON] and & & & & & & & \\ [PERSON], 2019) [24] & ✓ & 2 & & ✓ & & Static & Validation procedure \\ \hline ([PERSON], 2011) [8] & ✓ & & 1 & ✓ & ✓ & Dynamic & PMM \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._The ideal situation for the methods in the literature is represented by a technique that can fulfil the criteria of quantitative methodology, inclusion of internal and external perspective, industrial PMM consistency assessment, KPI comparison, and has a high ease of implementation and frequent recalculation rule. Therefore, identifying a method that combines all the required conditions will be a plus for the study, thus presenting a comprehensive and wide-ranging model that can easily take into account and evaluate all the facets possessed by a tree of indicators. It can be seen that the proposed approaches are more or less equally divided between qualitative and quantitative methodologies, allowing for a broad spectrum of implementable methods. Indeed, the critical analysis of the scientific literature allowed to determine this categorization, since no relevant \"hybrid/mixed\" model was found out in the current state-of-the-art.