Node A6 · Acronym decoder
SPI
Schedule Performance Index
What it actually means
Earned value divided by planned value — the fraction of scheduled work actually accomplished. SPI below 1.0 means behind schedule in earned-value terms, but it has a known blind spot: it drifts back toward 1.0 as a program finishes regardless of lateness, so critical-path analysis has to carry the schedule story late in a program.
Where you'll meet it
EVM dashboards, read alongside CPI and the IMS critical path.