What is a project baseline, and why save one before you start?
A baseline is a saved copy of your original plan. Here's how comparing it with the live schedule shows where a project drifted and when it started.
Three weeks into a project, someone asks why the launch date moved from March to April. You remember it moving. You don’t remember what it was originally, what changed, or when. The old version of the plan is gone, because you’ve been editing the only copy.
A baseline fixes that. It’s a snapshot of the plan taken at a point in time, kept separate from the schedule you keep working on.
What a baseline records
A baseline stores the planned start date, finish date and duration of each task as they stood when you saved it. The live schedule keeps changing as you update it. The baseline doesn’t, so the two can be laid side by side.
Where a task’s live dates differ from its baseline dates, that’s variance. A task with a baseline finish of the 12th and a live finish of the 19th has seven days of variance. You don’t have to remember the original date, because it’s stored.
When to save one
Save a baseline when the plan is agreed, before work starts. Not when it’s roughly right, and not after the first round of changes. The point is to capture what everyone signed up to.
Some teams save a second baseline after a formal change, such as a scope increase the client approved. That gives you a clean record of “original plan” and “plan after the approved change,” which makes arguments about blame much shorter.
What it tells you
A few things get easy to answer.
- Which tasks moved, and by how much, instead of a vague sense that things are late.
- Whether the slip is spread across many tasks or concentrated in one or two. One big slip on the critical path is a different problem from lots of small ones off it.
- Whether the project drifted early and stayed late, or fell behind steadily. Early drift usually means estimates were off. Steady drift usually means something keeps interrupting the team.
It’s also useful at the end. A project that finished two weeks late is a data point. A baseline comparison tells you which tasks produced those two weeks, which makes the next set of estimates better.
What it isn’t
A baseline is not a forecast and not a target you have to hit. Schedules are meant to change, and the live plan should reflect the best current understanding. The baseline just keeps the original in view so changes are visible instead of silent.
GanttPM lets you save a baseline and compare it against the live schedule, and it’s included in the free local plan. If you have a plan that’s about to start, download GanttPM, save the baseline first, and then start the work.