What is a Performance Measurement Baseline (PMB)?
The PMB is the integrated scope-schedule-cost baseline that earned value measures against: the WBS says what, the schedule says when, the time-phased budget says how much — fused into one approved reference. Change any leg through change control and the PMB re-baselines; drift any leg quietly and EV becomes fiction.
It includes contingency reserve, excludes management reserve — the exam likes that boundary.
Formula
PMB = scope baseline + schedule baseline + cost baseline (integrated)
Worked example
A satellite program's PMB: 1,400 WBS elements, each budgeted and time-phased. When a major antenna redesign is approved, the change adds $12M and four months through change control, and the PMB moves with it — so next quarter's CPI of 0.97 measures performance against the plan as it now legitimately is, not against a ghost plan nobody could follow.