# The Enhanced-Earned Value Management (E-EVM) Model: A Proposal for the Aerospace Industry
## 2 The Earned Value Management
The forecasting of EV metrics is fundamental in project management improvement by [18] pointing out the accuracy of estimating final cost and duration. Several scholars [19] consider that a functional distinction can be made between a top down (the use of a project control system which generates project-based performance metrics to give a general overview of the project performance) and a bottom up (control system in which detailed activity information needs to be available constantly during the project control process), by proposing the combination of elements of top down and bottom up control. Research is normally focused on improving the final cost and the duration estimates rather than improving the use of the planned value to predict the earned and actual cost values. However, the authors in [13] propose a straightforward method for improving the predictive power of the PV before executing a project. On the other hand, the authors in [20] proposed two new metrics combining EVM with Project Risk Management, allowing project managers to have better control and monitoring. These indexes allow project managers to analyze whether the project over-runs are within the expected variability or, on the contrary, there are some structural and systemic changes over the project life cycle. Another innovative proposal [21] consists of the integration of a graphical tool extending the Earned Value Management methodology. According to [22], a cost uncertainty analysis is vital in order to provide decision makers with a comprehensible model including different factors affecting funding exposure, and finally, estimate the cost of project. A novel control metric for projects which uses cost and/or time incentives was introduced by [23]. The Earned Incentive Metric (hereinafter, EIM) measures the deviation in the accrual of incentives rather than the time and cost performance relative to the planned schedule. More recently, differently conducted research studies [24] presented a new evaluation model of the EVM for the construction industry, blended with risk analysis, to improve the project's future performance forecasting defined under uncertain conditions by using linguistic variables represented by interval-valued triangular fuzzy numbers. Other works [25] consider that construction projects demand specific requirements along the life cycle of a project. Even though EVM has several advantages, it has not been widely used in the construction services sector in Poland [26]. A new research work proposed by [27] is to provide new awareness for the integration of linear and Taguchi-based methods to control quality, cost, schedule, and risk. More recently, the authors in [28] presented a new EVM tool, the so-called Duration Estimate at Completion (DEAC) model, whose main goal is forecasting the time estimate at completion. The DEAC model uses the actual time spent on each activity, either in progress or upon completion, where the performance is measured in time units. Finally, another recent research work [29] considers the growing awareness of the importance of the role of project management for sustainable development in order to investigate the existing conceptual and methodological overlap between the bodies of knowledge of EVM and sustainability in project management. As indicated, the EVM model needs improvement addressed to projects in the aerospace sector, motivated by the high number of subprojects integrated into the whole projects. This is why the next section is going to describe the aerospace sector and to review the empirical research in this sector.