Schedule baseline

Established

Also: Baseline schedule, Baseline

The approved version of the project schedule, frozen as the reference against which actual progress and changes are measured.

Explanation

A baseline is normally accepted by the owner or consultant early in the contract and changed only through formal change control. Progress updates record actual dates and remaining durations in the current schedule; variance against the baseline exposes slippage. Contracts usually require a baseline submission, periodic updates and a narrative explaining critical-path changes. Re-baselining is a formal decision, not a routine update. The schedule baseline is one of the reference points (with scope and cost) used in Earned value management.

Practical example

A school board accepts the contractor's baseline in month two. By month nine the update shows the roofing milestone 18 days behind the baseline, and the narrative attributes 10 days to a change directive for added skylights. That analysis supports an extension request.

Why it matters

Without a baseline there is nothing objective to measure delay against, which makes time claims hard to evaluate.

Standards and references

  1. A Guide to the Project Management Body of Knowledge (PMBOK Guide), Eighth Edition. Project Management Institute (PMI), 2025.Widely accepted professional interpretation
    Supports: Schedule performance domain; baselines as the reference for measuring performance in PMI practice · Status: Published November 2025; six principles and seven performance domains (governance, scope, schedule, finance, stakeholders, resources, risk).

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VDC Stack.io. (2026). Schedule baseline. In VDC Stack.io Knowledge Dictionary. Retrieved from https://vdcstack.io/dictionary/schedule-baseline/