To Complete Performance Index – EAC (TCPI-EAC)
TCPI-EAC tests whether the Estimate at Completion (EAC) is realistic. It shows the cost efficiency needed on the remaining work to finish at the EAC. Compare it with the cumulative Cost Performance Index (CPI), which is the efficiency achieved so far. If TCPI-EAC is well above CPI, the EAC assumes an improvement that hasn't happened yet. If it's well below, the EAC may be too pessimistic. The formula is TCPI-EAC = (BAC − BCWP) / (EAC − ACWP), where BAC is the Budget at Completion, BCWP is the Budgeted Cost for Work Performed, and ACWP is the Actual Cost of Work Performed.
Why it matters
An Estimate at Completion is a forecast, and forecasts drift toward optimism. TCPI-EAC is the check on one: it converts the estimate into the efficiency rate it implicitly assumes, so that assumption can be tested against the efficiency actually achieved. Without it, an EAC can sit unchallenged for months while the performance underneath says something different.
See also
FAQ
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