Earned Value Management (EVM) Formulas
Earned Value Management (EVM) Formulas
Earned Value Management (EVM) is a project management methodology that integrates scope, schedule, and cost to assess project performance and progress. It provides an objective way to measure project performance and forecast future performance.
Key Terms:
- Planned Value (PV): The authorized budget assigned to scheduled work. It is the budgeted cost of work scheduled (BCWS).
Formula: PV = Budget at Completion (BAC) × % Planned Complete
Example: A project has a total budget (BAC) of $100,000. By the end of the first month, 20% of the work was planned to be completed.
PV = $100,000 × 0.20 = $20,000
- Earned Value (EV): The value of the work performed in terms of the authorized budget assigned to that work. It is the budgeted cost of work performed (BCWP).
Formula: EV = Budget at Completion (BAC) × % Actual Complete
Example: For the same project with a BAC of $100,000, if 15% of the work is actually completed.
EV = $100,000 × 0.15 = $15,000
- Actual Cost (AC): The total cost incurred for the work performed. It is the actual cost of work performed (ACWP).
Example: For the 15% of work actually completed, the actual cost incurred was $18,000. AC = $18,000
Performance Measurement Formulas:
- Cost Variance (CV): Measures the difference between the earned value and the actual cost. It indicates whether the project is under or over budget.
Formula: CV = EV – AC
Interpretation:
CV > 0 : Under budget (favorable)
CV < 0 : Over budget (unfavorable)
CV = 0 : On budget
Example: Using the values above: CV = $15,000 (EV) – $18,000 (AC) = -$3,000
Interpretation: The project is $3,000 over budget.
- Schedule Variance (SV): Measures the difference between the earned value and the planned value. It indicates whether the project is ahead of or behind schedule.
Formula: SV = EV – PV
Interpretation:
SV > 0 : Ahead of schedule (favorable)
SV < 0 : Behind schedule (unfavorable)
SV = 0 : On schedule
Example: Using the values above: SV = $15,000 (EV) – $20,000 (PV) = -$5,000
Interpretation: The project is $5,000 behind schedule.
- Cost Performance Index (CPI): Measures the cost efficiency of the project work. It indicates the value earned for each dollar spent.
Formula: CPI = EV / AC
Interpretation:
CPI > 1 : Performing efficiently (under budget)
CPI < 1 : Performing inefficiently (over budget)
CPI = 1 : Performing on budget
Example: Using the values above: CPI = $15,000 (EV) / $18,000 (AC) = 0.83
Interpretation: For every dollar spent, only $0.83 worth of work was earned. The project is performing inefficiently in terms of cost.
- Schedule Performance Index (SPI): Measures the schedule efficiency of the project work. It indicates the rate at which the project is progressing compared to the plan.
Formula: SPI = EV / PV
Interpretation:
SPI > 1 : Performing efficiently (ahead of schedule)
SPI < 1 : Performing inefficiently (behind schedule)
SPI = 1 : Performing on schedule
Example: Using the values above: SPI = $15,000 (EV) / $20,000 (PV) = 0.75
Interpretation: The project is progressing at 75% of the planned rate. The project is performing inefficiently in terms of schedule.
Forecasting Formulas:
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Budget at Completion (BAC): The total planned budget for the project.
This is the total value of the project baseline.
Example: The total budget for the entire project is $100,000. BAC = $100,000
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Estimate At Completion (EAC): The expected total cost of completing all work.
There are several ways to calculate EAC, depending on assumptions about future performance:
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- EAC (if CPI is expected to continue for the remainder of the project):
This assumes that the current cost efficiency will continue.
Formula: EAC = BAC / CPI
Example: Using BAC = $100,000 and CPI = 0.83: EAC = $100,000 / 0.83 = $120,481.93 Interpretation: At the current rate of spending, the project is expected to cost approximately $120,481.93 to complete.
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- EAC (if future work will be performed at the budgeted rate):
This assumes that past cost variances are atypical and future work will be completed as planned.
Formula: EAC = AC + (BAC – EV)
Example: Using AC = $18,000, BAC = $100,000, EV = $15,000: EAC = $18,000 + ($100,000 – $15,000) = $18,000 + $85,000 = $103,000
Interpretation: If future work is performed at the budgeted rate, the project is expected to cost $103,000 to complete.
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- EAC (if CPI and SPI are expected to influence future work):
This is a more complex formula that considers both cost and schedule efficiency.
Formula: EAC = AC + (BAC – EV) / (CPI × SPI)
Example: Using AC = $18,000, BAC = $100,000, EV = $15,000, CPI = 0.83, SPI = 0.75:
EAC = $18,000 + ($100,000 – $15,000) / (0.83 × 0.75) = $18,000 + $85,000 / 0.6225 = $18,000 +
$136,546.18 = $154,546.18
Interpretation: Considering both cost and schedule efficiency, the project is expected to cost approximately
$154,546.18 to complete.
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- EAC (if future work is re-estimated): This is used when a new estimate to complete (ETC) is provided.
Formula: EAC = AC + ETC
Example: If a new estimate to complete the remaining work (ETC) is $90,000: EAC = $18,000 (AC) + $90,000 (ETC) = $108,000
Interpretation: Based on the new estimate for remaining work, the project is expected to cost $108,000 to complete.
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Estimate To Complete (ETC): The expected cost to complete the remaining project work.
Formula: ETC = EAC – AC (based on the chosen EAC calculation)
Example: Using EAC = $120,481.93 (from EAC = BAC/CPI) and AC = $18,000:
ETC = $120,481.93 – $18,000 = $102,481.93
Interpretation: The remaining work is expected to cost $102,481.93.
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- ETC (if future work efficiency is assumed to be the current CPI):
Formula: ETC = (BAC – EV) / CPI
Example: Using BAC = $100,000, EV = $15,000, CPI = 0.83: ETC = ($100,000 – $15,000) / 0.83 = $85,000 / 0.83 = $102,409.64
Interpretation: The remaining work is expected to cost $102,409.64, assuming current cost efficiency.
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Variance At Completion (VAC): The projected difference between the total planned budget (BAC) and the expected total cost at completion (EAC). It indicates the expected budget overrun or underrun.
Formula: VAC = BAC – EAC
Example: Using BAC = $100,000 and EAC = $120,481.93: VAC = $100,000 – $120,481.93 = -$20,481.93
Interpretation: The project is expected to be $20,481.93 over budget at completion.
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To Complete Performance Index (TCPI): The calculated CPI that must be achieved on the remaining work to meet a specified management goal (BAC or EAC). It indicates the future cost efficiency required to meet the target.
TCPI (to meet BAC): This indicates the efficiency needed to finish the project within the original budget.
Formula: TCPI_BAC = (BAC – EV) / (BAC – AC)
Example: Using BAC = $100,000, EV = $15,000, AC = $18,000:
TCPI_BAC = ($100,000 – $15,000) / ($100,000 – $18,000) = $85,000 / $82,000 = 1.036
Interpretation: To finish within the original budget, the remaining work must be completed at an efficiency of 1.036. This means for every dollar spent, $1.036 worth of work must be earned.
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TCPI (to meet EAC): This indicates the efficiency needed to finish the project within the current Estimate At Completion.
Formula: TCPI_EAC = (BAC – EV) / (EAC – AC)
Example: Using BAC = $100,000, EV = $15,000, EAC = $120,481.93, AC = $18,000:
TCPI_EAC = ($100,000 – $15,000) / ($120,481.93 – $18,000) = $85,000 / $102,481.93 = 0.829
Interpretation: To finish within the current EAC, the remaining work must be completed at an efficiency of 0.829. This means for every dollar spent, $0.829 worth of work must be earned.