## 2 Theoretical Background
### Comparative Analysis of Methods
Moreover, having the possibility of giving practical grounding to a quantitative methodology or being able to develop a system theorized in the scientific literature concretely are possibilities equally to be taken into account for the assessment of the coherence of a tree of indicators. However, as emphasized above, a quantitative methodology is preferable so that a relevant practical application can be made to an already existing and proven effective evaluation method. Analyzing the criterion of ease of implementation, it can be seen that there are works that possess one as the result of the analysis; this value indicates that the approach presents a high complexity in terms of practical application of the method. This result suggests that the proposed procedure either presents a complex algorithm, an elaborate structure for Analyzing the results of the questionnaires or presents graphs with links between values that require a very long and complex analysis, which in practice would be too difficult to implement and would not be accepted by those who have to implement it. The methods that respond with two to the same item show an application technique of neutral difficulty, having characteristics that, by construction, present a minimal residual problem that does not make them immediately applicable, and the timing of their application must nevertheless be taken into account. Consequently, the items in the table with a 3 to the criterion in question are those that best combine short application times and simplicity of calculation or method establishment; for these reasons, methodologies with this value are considered among the best implementable within organizations. Continuing, it can be seen that in the entry showing the recalculation frequency of the method, the \"static\" entries are multiple: this is a result we wish to avoid since it is well known that boundary conditions, especially in competitive environments, can change continuously over time, leading to the need to revise the strategy frequently. Therefore, to have a structure that does not provide for a subsequent recalculation derived from changing conditions, such as those exemplified above, is to be considered a significant shortcoming, as such considerations are considered fundamental and necessary for successful and reliable evaluation work. Some approaches possess a periodic recalculation frequency, which means that after a specific fixed interval of time, there will be a reassessment, but this too is not entirely satisfactory as a periodic revision. However, it gives dynamism to the model and provides for reassessments that may prove to be unnecessary, given that the conditions or environments have not changed significantly. Moreover, if something were to change, a re-evaluation of the indicator tree would not be required, but one would have to wait until the recalculation period for an update. This leads to inefficiencies in the company as it will measure its performance inappropriately with metrics that have become useless as long as there is no update. Possessing the peculiarity of 'dynamic' makes a methodology very efficient and responsive, as it prevents the company from wasting resources in measuring performance that is no longer needed and obsolete. Indeed, this peculiarity will undoubtedly be more demanding to implement than the periodic one, as it requires constant monitoring of the environment and a consequent re-evaluation when specific changes occur. Still, it avoids problems from measuring metrics that are no longer necessary or incorrect. By doing so, one focuses more on performance while still being able to be competitive and responsive. It can be seen that, concerning the criteria of including the internal and external perspective, assessing the consistency of the industrial PMM and comparing KPIs, it is tough to find a method that succeeds in satisfying all three. Still, often only a couple of them can be happy, or there are even approaches that stop at just one.