Performance Measurement Baseline (PMB)

The Performance Measurement Baseline (PMB) is the approved, time-phased budget for the entire project scope, excluding management reserve. It represents the integration of the work breakdown structure, the schedule, and the cost estimate into a single reference plan. For each control account, the PMB contains a budget spread over time — a planned value profile — that defines how much work is expected to be done in each period. The sum of all control account budgets equals the PMB, and the sum of the PMB and management reserve equals the total authorised budget (TAB).

Establishing the PMB is the culmination of the project planning and estimating process. It requires that scope is defined (WBS complete), the schedule is baselined (logic-linked, resource-loaded, and approved), the cost estimate is accepted, and the budget has been allocated to work packages. A programme that runs EVM without a properly established PMB is, in practice, just tracking actuals against a rough plan — the SPI and CPI calculations will be meaningless because there is no rigorous planned value profile to compare against.

The PMB should be treated as a controlled document. Changes to the PMB — whether from scope changes, design development, risk drawdowns, or re-planning — must go through formal change control and be documented with version control and an audit trail. An undocumented PMB change is a governance failure that undermines the integrity of every performance metric calculated against it. Project boards and independent monitors should periodically audit the PMB change history to ensure that re-planning has been properly authorised and that the baseline has not been adjusted in ways that artificially improve performance metrics.