Schedule baseline is the approved version of a schedule model that can be changed only through formal change control procedures and is used as a basis for comparison to actual results. The project management contains the schedule baseline, used as a reference to compare with the actual results to determine if a change, corrective action, or preventive action is necessary.

In the project management, duration estimates may include contingency reserves, sometimes referred to as time reserves or buffers, into the project schedule to account for schedule uncertainty. Contingency reserves are the estimated duration within the schedule baseline. Schedule baseline is one of the elements of project management that may be updated.

The changes to the schedule baseline are incorporated in response to approved change requests related to project scope changes, activity resources, or activity duration estimates. It may be updated to reflect changes caused by schedule compression techniques. Such documents of the schedule baseline are the accepted schedule performance measures, including start to finish dates, which also indicates when the project costs will be incurred. Because of new work (or omitted work) generated by the risk responses, schedule baseline may be updated to reflect those changes.