Summer maths


Project managers can use multiple equations to track the progress of their projects against their expectations. Most of the calculations compare measurements of actual costs or time used to what was planned. A few calculations figure what performance would be required to get the project back to the planned values.

Related: earned value management

The following table shows some of the equations...

Initials Spelled Out Formula
AC actual cost AC = the actual cost of all the work completed by a specific time

Also known as ACWP (Actual Cost for Work Performed)

BAC budget at completion BAC = the sum of all the planned work to be performed to complete the project; the project cost baseline
CPI cost performance index CPI = EV / AC
CV cost variance CV = EV - AC
EAC estimate at completion four different formulas depending on the situation, see estimate at completion
ETC estimate to complete ETC = EAC - AC
EV earned value EV = the sum of the planned value of the work that has been completed by a particular time

Also known as BCWP (Budgeted Cost for Work Performed)

PV planned value PV = the sum of the value assigned to the work planned by a particular time
SPI schedule performance index SPI = EV / PV (where the timeframe for the EV and PV are the same)
TCPI to complete performance index TCPI = (BAC-EV) / (BAC-AC)


See table 7.1 in section of the PMBOK for an "Earned Value Calculations Summary Table".