Schedule Performance Index
SPI = EV/PV
EV = Earned Value
PV = Planned Value
< 1 behind schedule
= 1 on schedule
> 1 ahead of schedule
Cost Performance Index
CPI = EV/AC
EV = Earned Value
AC = Actual Cost
< 1 Over budget
= 1 On budget
> 1 Under budget
Schedule Variance
SV = EV-PV
EV = Earned Value
PV = Planned Value
< 0 Behind schedule
= 0 On schedule
> 0 Ahead of schedule
Cost Variance
CV = EV-AC
EV = Earned Value
AC = Actual Cost
< 0 Over budget
= 0 On budget
> 0 Within budget
Estimate At Completion, if original is flawed
EAC = AC+ETC
AC = Actual Cost
ETC = Estimate to Completion
if the original estimate is based on wrong data/assumptions or circumstances have changed ETC mentioned here is a ‘new ETC’
Estimate At Completion, if BAC remains the same
EAC = AC+BAC-EV
AC = Actual Cost
BAC = Budget at completion
EV = Earned Value
the variance is caused by a onetime event and is not likely to happen again
Estimate At Completion, if CPI remains the same
EAC = BAC/CPI
BAC = Budget at completion
CPI = Cost performance index
if the CPI would remain the same till end of project, i.e. the original estimation is not accurate
Estimate At Completion, if substandard performance continues
EAC = AC+(BAC-EV)/(CPI*SPI)
AC = Actual Cost
BAC = Budget at completion
EV = Earned Value
CPI = Cost Performance Index
SPI = Schedule Performance Index
use when the question gives all the values (AC, BAC, EV, CPI and SPI), otherwise, this formula is not likely to be used
To Complete Performance Index (TCPI)
TCPI = (BAC-EV)/ (BAC-AC)
BAC = Budget at completion
EV = Earned value
AC = Actual Cost
TCPI is basically – Remaining Work / Remaining Funds
< 1 Under budget
= 1 On budget
< 1 Over budget
If EAC is available use EAC-AC instead of BAC-AC
Estimate To Complete (ETC)
ETC = EAC-AC
EAC = Estimate at Completion
AC = Actual Cost
Variance At Completion (VAC)
VAC = BAC-EAC
BAC = Budget at completion
EAC = Estimate at Completion
Inference
For variances like SV, CV and VAC – negative is bad, positive is good
For indices like CPI and SPI – less than 1 is bad, more than 1 is good. However, the opposite is true for TCPI
Diagrammatic Representation
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