Editing Earned value management (section)

=== To-complete performance index (TCPI) ===

To-complete performance index (TCPI) is an earned value management measure that estimates the cost performance needed to achieve a particular management objective.{{sfn | Project Management Institute | 2021 | loc=§2.7.2.7 Forecasts}}
The TCPI provides a projection of the anticipated performance required to achieve either the BAC or the EAC. TCPI indicates the future required cost efficiency needed to achieve a target BAC (Budget At Complete) or EAC (Estimate At Complete). Any significant difference between CPI, the cost performance to date, and the TCPI, the cost performance needed to meet the BAC or the EAC, should be accounted for by management in their forecast of the final cost.

For the TCPI based on BAC (describing the performance required to meet the original BAC budgeted total):

<math>TCPI_{BAC} = { BAC - EV \over BAC - AC }</math>

or for the TCPI based on EAC (describing the performance required to meet a new, revised budget total EAC):

<math>TCPI_{EAC} = { BAC - EV \over EAC - AC }</math>

This implies, that if revised budget (EAC) is calculated using Earned Value methodology formula (BAC/CPI), then at the moment, when TCPI based on EAC is first time calculated, it will always be equal to CPI of a project at that moment. This happens because when EAC is calculated using formula BAC/CPI it is assumed, that cost performance of the remaining part of the project will be the same as the cost performance of the project to date.

[[File:Earned Value Calculations TCPI EAC and ETC.png|thumb|alt=Earned Value Calculations: TCPI, EAC and ETC|To-Complete Performance Index (TCPI) for 3 scenarios.]]

The graph illustrates  three scenarios outlined in PMI's "''Process Group: A Practice Guide''" (2022 edition, p.&nbsp;311):
# The To-Complete Performance Index (TCPI) required to complete the project on plan, assuming the Budget at Completion (BAC) remains unchanged (i.e., '''EAC = BAC''').
# The Estimated At Completion (EAC) calculated under the assumption that the Cost Performance Index (CPI) remains constant (i.e., '''TCPI = CPI''').
# The EAC calculated under the assumption that future work will be accomplished at the planned rate (i.e., '''TCPI = 1''').