Schedule baselines are projected schedules, based on information that is known to date. Dates and estimates in baseline schedules are expected to change through execution.
To baseline a schedule, retain a copy of the original estimates, start dates, completion dates, and other information the project manager may wish to baseline. During execution, update the schedule with actual information pertaining to dates. Do not overwrite the baseline values.
Why baseline a schedule?
- provides ability to assess performance
- a project manager can answer questions from sponsor and governance about why things aren't getting done as expected
- make a judgement whether project on track by comparing actual dates to projected dates through either
- judgement
- adding a value for Percent Complete against tasks and milestones
- earned value calculations of a schedule performance indicator by comparing planned vs actual
- trending and forecasting are possible with earned value calculations
- referring to a baseline schedule during execution provide a trigger when actual values differ from projected baseline values. The project manager should look into constraints such as scope and resources to investigate where potential issues may be slowing down the project
- provides ability to improve future schedule estimates