## 3 Methodology
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Class II**} & \multicolumn{2}{c}{**Class III**} & \multicolumn{2}{c}{**Class IV**} \\ \cline{2-7}
**DMU** & **Year** & **Efficiency** & **DMU** & **Year** & **Efficiency** & **DMU** & **Year** & **Efficiency** \\ \hline
37 & 2021 & 13\% & 37 & 2020 & 39\% & & \\
38 & 2021 & 4\% & 38 & 2020 & 73\% & & \\
39 & 2021 & 100\% & 39 & 2020 & 100\% & & \\
40 & 2021 & 83\% & 40 & 2020 & 16\% & & \\
41 & 2021 & 67\% & 41 & 2020 & 38\% & & \\
42 & 2021 & 100\% & 42 & 2020 & 7\% & & \\
43 & 2021 & 57\% & 43 & 2021 & 31\% & & \\
44 & 2021 & 45\% & 44 & 2021 & 2\% & & \\
45 & 2021 & 87\% & 45 & 2021 & 6\% & & \\
46 & 2021 & 100\% & 46 & 2021 & 100\% & & \\
47 & 2021 & 100\% & 47 & 2021 & 4\% & & \\
48 & 2021 & 23\% & 48 & 2021 & 19\% & & \\
49 & 2021 & 31\% & 49 & 2021 & 100\% & & \\  & & & 50 & 2021 & 22\% & & \\  & & & 51 & 2021 & 100\% & & \\  & & & 52 & 2021 & 61\% & & \\  & & & 53 & 2021 & 100\% & & \\  & & & 54 & 2021 & 55\% & & \\ Average & & 61\% & & & 45\% & 67\% & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._  
Figure 2: Average efficiencies by classes over the years. effort, while failure in the more challenging class IV projects could jeopardize future revenues. Therefore, the PMO focuses on expediting simple projects and does not take risks with expensive or revenue-focused projects. Given the wrong results in class III, by the end of 2020, the PMO management had decided to prioritize such a class, which was reflected in the 2021 results. To assess the appropriateness of average efficiency in project control, this study also computed efficiencies weighted by cost and time. The rationale behind employing weighted indicators lies in the fact that maintaining cost efficiency, often associated with low-cost projects, holds less significance than achieving an intermediate efficiency level in high-cost projects. The same principle applies to project completion time. While a short, high-efficiency project can help mitigate resource idieness in critical areas, a large project with intermediate efficiency has the potential to reduce more idle hours. Hence, considering both cost and project completion time may be relevant in evaluating the implications of efficient management. Equations (4) and (5) below depict cost and time efficiency, respectively. \[Eff_{cw}=\frac{\sum{eff_{i}}C_{i}}{\sum{C_{i}}} \tag{4}\]  
\[Eff_{tw}=\frac{\sum{eff_{i}}T_{i}}{\sum{T_{i}}} \tag{5}\]  
where:  
\(Eff_{cw}\) and \(Eff_{tw}\) = cost- and time-weighted efficiencies;  
\(C_{i}\) and \(T_{i}\) = cost and time to completion of the \(i\)th project;  
\(\Sigma C_{i}\) and \(\Sigma T_{i}\) = total cost and total time to completion of all the projects. Table 7 presents the weighted and average efficiencies for the different classes. Notably, Class II and IV exhibited a major disparity between average and cost-weighted efficiency. In Class II, projects with higher costs received lower priority, leading to a 4.8 percentage point difference below the average. Conversely, in Class IV, the PMO prioritized projects with larger budgets, resulting in a positive difference of 9.5 percentage points, which was an outcome that made sense. Appendix B shows the entire calculation for weighted efficiencies. Table 8 presents the partial success rate of projects by class, showing the absolute number and the percentage of projects that finished on time and at the expected cost. It is interesting to note that the greater the class (and the value), the greater the percentage on time, which reflects the initial prioritization given by PMO to class IV projects. The low accuracy in cost in class IV projects highlights that on-time performance is achieved, jeopardizing cost. Regarding the cost, class II is significantly more accurate than the other classes due to such projects' low complexity and uncertainty.