How many baselines should a project have?

One approved baseline at any time. Additional 'current' or 'forecast' schedules are maintained for working purposes but the baseline only changes through formal re-baselining.

When should a project be re-baselined?

Only after an approved change that materially alters scope, funding, or completion date — never to mask slippage.

Which calculators on PMMilestone.org apply to Baseline Schedule?

For Baseline Schedule, the most relevant tools on the flagship platform are the Schedule Health Checker and SPI Calculator (Earned Schedule SPI(t)). They reproduce the formulas referenced in this entry against your own project data.

What is a common misconception about Baseline Schedule?

That a baseline schedule passing the DCMA 14-point check is good for the life of the project. In practice, schedule quality must be re-checked at every monthly update — out-of-sequence work, broken logic and constraint creep degrade quality rapidly after baseline.

Which related encyclopedia entries should I read alongside Baseline Schedule?

Read Critical Path Method, Schedule Performance Index and Earned Schedule next. The full A–Z is available in the PMMilestone Encyclopedia, and quick one-line definitions live in the PM Glossary on the flagship platform.

How does Dr. Hassan Eliwa's research treat Baseline Schedule?

Dr. Hassan Eliwa's research focuses on owner-side project controls, schedule integrity and forensic delay analysis on capital construction and power programmes. Baseline Schedule is treated through that lens — what a planning or controls engineer is expected to do with it on a live project, not its textbook definition alone. See the full research library at PMMilestone Research Articles.

How is Baseline Schedule defined on PMMilestone Research & Insights?

The approved, time-phased plan used as the reference against which project performance is measured. For the full treatment, see the definition, principles, applications and related entries above — every encyclopedia entry follows the same research-grade structure.

Schedule Management · Letter B

Baseline Schedule

The approved, time-phased plan used as the reference against which project performance is measured.

By Dr. Hassan Khames Eliwa, PhD · Updated 2025-03-18

Definition

A Baseline Schedule is the formally approved version of the project schedule, frozen and used as the reference for measuring performance, calculating variances, and supporting change control. It is the contractual yardstick on EPC and infrastructure projects and the basis for delay analysis.

History

The concept emerged with CPM scheduling in the late 1950s and matured through the U.S. Department of Defense's Cost/Schedule Control Systems Criteria (C/SCSC) of 1967, the precursor to today's Earned Value Management Systems. AACE Recommended Practice 38R-06 codifies modern baseline-development standards.

Principles

Complete WBS coverage — every scope item is reflected.
Logical, fully networked activity sequence with no open ends.
Realistic durations supported by productivity rates and resource availability.
Calendars that reflect actual working conditions and holidays.
Formal approval and version control after baselining.

Applications

The baseline serves four primary uses: progress measurement, earned value reporting, change-impact analysis, and prospective/retrospective delay analysis. On capital projects it is often contractually mandated and must be accepted by the owner before notice-to-proceed.

Real Example

On a 1.8 GW gas-fired power plant the baseline was developed at a Level 3 schedule density (~ 6,500 activities) and accepted by the owner 90 days after award. Two re-baselines were approved during execution following major scope changes; each re-baseline was version-controlled and the previous baseline archived for forensic analysis.

Best Practices

Run a DCMA 14-point schedule health check before baselining.
Resource-load the schedule and reconcile with the cost baseline.
Avoid open-ended activities, dangling logic, and excessive constraints.
Keep total float realistic — schedules with > 30% high-float activities are usually under-logiced.

Common Mistakes

Submitting a baseline padded with hard constraints to mask aggressive durations.
Not resource-loading, then over-promising delivery.
Re-baselining to hide poor performance rather than to absorb genuine scope change.

References

AACE International, Recommended Practice 38R-06 — Documenting the Schedule Basis.
DCMA, 14-Point Schedule Assessment.

Frequently Asked Questions

How many baselines should a project have?
One approved baseline at any time. Additional 'current' or 'forecast' schedules are maintained for working purposes but the baseline only changes through formal re-baselining.
When should a project be re-baselined?
Only after an approved change that materially alters scope, funding, or completion date — never to mask slippage.
Which calculators on PMMilestone.org apply to Baseline Schedule?
For Baseline Schedule, the most relevant tools on the flagship platform are the Schedule Health Checker and SPI Calculator (Earned Schedule SPI(t)). They reproduce the formulas referenced in this entry against your own project data.
What is a common misconception about Baseline Schedule?
That a baseline schedule passing the DCMA 14-point check is good for the life of the project. In practice, schedule quality must be re-checked at every monthly update — out-of-sequence work, broken logic and constraint creep degrade quality rapidly after baseline.
Which related encyclopedia entries should I read alongside Baseline Schedule?
Read Critical Path Method, Schedule Performance Index and Earned Schedule next. The full A–Z is available in the PMMilestone Encyclopedia, and quick one-line definitions live in the PM Glossary on the flagship platform.
How does Dr. Hassan Eliwa's research treat Baseline Schedule?
Dr. Hassan Eliwa's research focuses on owner-side project controls, schedule integrity and forensic delay analysis on capital construction and power programmes. Baseline Schedule is treated through that lens — what a planning or controls engineer is expected to do with it on a live project, not its textbook definition alone. See the full research library at PMMilestone Research Articles.
How is Baseline Schedule defined on PMMilestone Research & Insights?
The approved, time-phased plan used as the reference against which project performance is measured. For the full treatment, see the definition, principles, applications and related entries above — every encyclopedia entry follows the same research-grade structure.