What is the difference between the PMB and the budget at completion?

The budget at completion is a single number, the total authorized budget for the project. The performance measurement baseline is that same budget spread across time and scope: the budget at completion distributed into control accounts and laid out period by period according to the schedule. One is the total; the other is the plan for when and where that total gets earned. The cumulative sum of the baseline over time is exactly the planned-value curve, so BAC is simply the value the PMB reaches at the final period.

When can the performance measurement baseline change?

Only through formal change control. When an owner approves a change order that adds scope and budget, that authorized work is folded into the baseline and the baseline legitimately grows. What must never happen is a quiet re-cut, moving budget around or sliding the planned curve to match whatever actually happened, because a baseline that chases reality makes schedule variance vanish and the whole method goes blind. A disciplined project treats the baseline as frozen between approved changes, which is why earned value and a loose budget cannot coexist.

Is management reserve part of the baseline?

No. Management reserve is budget held back for unforeseen work that is within the project scope but not yet planned in detail. It sits above the performance measurement baseline, controlled by management, and is not included in any earned-value calculation. When a reserve is drawn down for a specific newly-defined scope, that work is moved into a control account and the baseline grows by that amount. Keeping reserve outside the baseline is what lets earned value measure performance against the real plan rather than against a cushion.

Construction Glossary · Earned Value

PerformanceMeasurementBaseline

Earned value measures against something. That something is the PMB: the frozen, time-phased budget. Let it drift and every variance you compute becomes meaningless.

Definition

The performance measurement baseline (PMB) is the frozen, time-phased budget for all authorized work, organized into control accounts, that earned value measures performance against. Its cumulative shape over time is the planned-value curve. It changes only through formal change control, and management reserve is held outside it.

Budget, broken into control accounts

The baseline is the budget at completion divided into control accounts, each a slice of scope, schedule, and budget someone owns. Together they sum to BAC. Management reserve stays outside.

Sitework Structure MEP Finishes

The three rules that keep it honest

Frozen between approved changes

The baseline holds still so performance has a fixed thing to measure against. Nudging it to match reality is how schedule variance quietly disappears.

Organized into control accounts

Each control account is where a slice of scope, schedule, and budget meet and are owned. The accounts sum to the budget at completion.

Management reserve sits outside it

Reserve for unforeseen in-scope work is held above the baseline and excluded from earned value until it is drawn into a control account.

How POD keeps the baseline frozen

POD holds the original budget as an immutable baseline and tracks changes as a versioned performance measurement baseline, so an approved change grows the plan without erasing what it was before. Every variance and index is measured against that pinned baseline, which is what stops the plan from quietly chasing reality and keeps schedule variance meaningful.

Baseline vs rebaseline guide

Frequently asked questions

The fixed point everything measures from

A frozen baseline is what makes earned value honest. With it set, the schedule reading can finally be measured in time, not just dollars.

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