PSI - Issue 22

Rosário Oliveira / Procedia Structural Integrity 22 (2019) 151–159

154

4

Rosário Oliveira/ Structural Integrity Procedia 00 (2019) 000 – 000

The application of EVM requires an initial effort in the planning of work to be done, particularly with regards to the definition of the activities to consider, the estimate of its duration and the costs inherent in each. According to [8] this model can be used as a technique to support the management in performance evaluation of the execution of the work, providing status and performance indicators relating schedule and cost; on the valuation date, based on the amount of actual work performed it compares its performance against what was planned and facilitates forecasts for the completion of the work. EVM uses three reference variables that are based on the fundamental concepts of values: 1) Planned Value (PV) or Budgeted Cost of Work Scheduled (BCWS) is the budgeted cost for the planned work (estimated cost), which is the value of the approved budgets in accordance with planned, it gives an indication of the overall cost of the work in the baseline, and allows to predict the costs to be invested throughout the execution; 2) Earned Value (EV) or Budgeted Cost of Work Performed (BCWP) is the budgeted cost for the tasks performed (income, values acquired or measured), it is the budgeted amount for the amount of work performed up to the date of status (time of evaluation), it is determined from the percentage of performance of the tasks; 3) Actual Cost (AC) or Actual Cost of Work Performed (ACWP) is the actual cost of the tasks performed, it consists of the value of the actual costs of the work carried out until the state date, it is determined from the actual costs spent on the job executed. In monitoring the deadline and the cost of the work, EVM compares the baseline with the one performed on the status date, which it is the control date. With PV, EV and AC a set of indicators is obtained that quantifies and evaluates the state and performance of the work at the control date. According to [8] these indicators are index of state, performance and forecast. Status indicators reflect the Cost Variation (CV) and the Schedule Variance (SV) of the planned. Cost Variance (CV = EV-AC) measures the difference between the earned values of the work performed (values of the measurement of the work) and the values of the actual cost of the work performed (values of the actual costs of the work performed on the work). The status date, if CV <0 then the work is costing more than the budget, if CV> 0 then the work is costing less than forecasted budget. Schedule Variation (SV = EV-PV) measures the difference between the earned value from the work performed (measurement of the work) and the values of the budget for the work performed (planned values for the work performed). At the state date, if SV <0 then the work is delayed relative to the planned, if SV> 0 then the work is ahead of schedule. Performance indicators are the Cost performance index (CPI) and the Schedule Performance Index (SPI). On the state date, the Cost Performance Index (CPI = EV / AC) establishes the relation between the earned values (EV) and the actual cost (AC); the CPI translates the rate between the earned values and the values spent in the same period. At the state date, if CPI = 1 then the amount spent was fully earned, the work is within the planned budget; if CPI <1 then the amount spent is greater than the amount earned, the work is costing more than the planned budget; if CPI> 1 then the amount spent is less than the amount earned, the work is costing less than the scheduled budget. For example, if we obtain a CPI = 0.90 we can conclude that for each unit of capital invested only 90% is physically converted into output, that is, the loss for each monetary unit spent is 10%. On the state date, the Schedule Performance Index (SPI = EV / PV) establishes the relation between the earned values (EV) (measurement of the work) and the planned values (PV) (values planned for the work); the SPI translates the rate between measured values and planned values over the same period. Thus, at the state date, if SPI = 1 then the work is proceeding as planned; if SPI <1 then the work is behind schedule; if SPI> 1 then the work is ahead of schedule. For example, if we get a SPI = 0.80 we can conclude that 80% of the work planned was executed. The forecast indicators indicate estimates of time and cost at the end of the works. These are Estimated At Completion (EAC), Variation At Completion (VAC) and Time At Completion (TAC).