Baseline

When the plan is approved, save a copy of its tasks and dates. Keep that copy unchanged while you update the live plan. It records what the team agreed to at the start.

Comparing today's chart with the baseline shows which tasks have moved and by how much. That gives a status discussion a specific reference: a task is three days later than planned, for example.

A large program may use a formal change-control process to approve a new baseline. On a small project, saving the approved chart may be enough. Take that copy before work starts so early delays are included in the comparison.