# The Enhanced-Earned Value Management (E-EVM) Model: A Proposal for the Aerospace Industry
## 5 Results  
### General Procedure E-EVM Models  
This section focuses on demonstrating the results after the description of the new E-EVM model in Section 4. As indicated, this is a simulation of a big aerospace project where the WBS has been disaggregated into 4000 subprojects. The projects are measured in hours as the unit cost which allows us to know the times without using the ESM [5; 6; 7], EDM [8], or EVM [9] models.  
In Table 3, the main parameters of project performance have been selected.  
In order to facilitate comprehension of the whole procedure, a set up \"color\" code system has been proposed in Figure 2. Colors green and blue are linked directly to the two improvements implemented in the E-EVM model. The first improvement, that is to say,  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Characteristics** & **EVM** & **E-EVM** \\ \hline Metrics & _EV_, _AC_, _PV_ & _EV_(_i_), _AC_(_i_), _PV_(_i_) \\ Performance indicator (variances) & _CV_, _SV_ & _CV_(_i_), _SV_(_i_) \\ Performance indicator (indices) & _CPI_, _SPI_ & _CPI_(_i_), _SPI_(_i_) \\ Forecast method & _EAC_, _ETC_, _VAC_ & _EAC_(_i_), _ETC_(_i_), _VAC_(_i_) \\ “Double” vision cost/time (first improvement) & No & Yes \\ Inputs & Cost units & Cost and time units \\ Outputs & Cost units & Cost and time units \\ Large-size work breakdown structure & No & Yes \\ (WBS; second improvement) & One project & \(i\) projects \\
\begin{tabular}{c} Continuous revision and improvement \\ usage \\ Decision-making process \\ \end{tabular} & One project & \(i\) projects \\ \hline \hline \end{tabular}
\end{table}
Table 2: EVM and E-EVM. Features and main characteristics. Source: Own elaboration.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Condition** & **Meaning** \\ \hline \multirow{2}{*}{Schedule Variance (\(SV\))} & _SV_ **\textless{} 0** & **Behind schedule** \\  & _SV_ **\textgreater{} 0** & **Ahead of schedule** \\ \hline Schedule Performance Index & _SPI_ **\textless{} 1** & **Non-efficient use of time** \\ (_SPI_) & _SPI_ **\textgreater{} 1** & Efficient use of time \\ \hline \multirow{2}{*}{Cost Variance (\(CV\))} & _CV_ **\textless{} 0** & **Over budget** \\  & _CV_ **\textgreater{} 0** & Under budget \\ \hline \multirow{2}{*}{Cost Performance Index (_CPI_)} & _CPI_ **\textless{} 1** & **Non-efficient use of resources** \\  & _CPI_ **\textgreater{} 1** & Efficient use of resources \\ \hline \hline \end{tabular} Note: Boldface means unwanted conditions.  
\end{table}
Table 3: Main EVM parameters. Source: Own elaboration.  
the use of units of time (hours) instead of units of cost (EUR) will be assigned to the green color. Moreover, the second one, that is to say, the disaggregation into subprojects, will be assigned to the blue color. Obviously, this color system will provide with a more visual and intuitive system for the follow up of the whole process.  
The general procedure followed is shown in Figure 3, where different stages have been defined with the colors previously mentioned. A distinction can be made between the projections, main parameters, control limits and subprojects out of the range of computation, in blue, and the cost versus time computation and overall project output, in green, which means that they are linked to double vision.  
In order to understand Figure 3, the notation requires some explanation:  
* \(N(i)\): Set of subprojects \(i\), for every \(i\) belonging to the WBS.  
Figure 3: E-EVM blocks diagram model. Source: Own elaboration.  
Figure 2: Color code legend. Source: Own elaboration.  
* _AC, PV, EV, BAC,_ and hourly rate: Set of inputs of each subproject \(i\).
* _CV(i); CPI(i); SV(i); SPI(i); EAC(i); ETC(i); and VAC(i):_ Set of output of each subproject \(i\) (column vectors).
* UpL_CV and LoL_CV: Upper and lower limit of Cost Variance.
* UpL_SV and LoL_SV: Upper and lower limit of Schedule Variance.