Compare against a named plan: see what has moved since the start
An up-to-date schedule tells you where you stand. It does not tell you what has changed. By naming a version of the plan and comparing against it, you see at a glance what has slipped, and by how much.
named plan “October 21 version”
The buffer absorbed the delay: the objective holds, with no margin left.
A living schedule changes every week. That is normal; it is even a sign that it is being used. But after many small corrections, nobody can say what has moved since the initial decision.
Name a version of the plan
A named plan is a snapshot of the schedule at a given date: "October 21 version". You create it at an important decision, a kick-off or a trade-off. It does not move afterwards. It is the reference.
Compare, task by task
The comparison shows, under each task, its position in the named plan. In our example of a packaging line relocation, three tasks have slipped by 3 days since October 21: new site preparation, reassembly and production trials.
The restart milestone, however, has not moved: the buffer planned before the restart absorbed the delay. That is valuable information. It says the objective holds, and that there is no margin left.
What the comparison changes in meetings
Instead of debating the finish date, you look at what has slipped and why. The discussion is about three specific tasks, not a general impression of delay.
Key points
- name a version of the plan at each important decision;
- compare task by task, not only the finish date;
- watch the buffer: a milestone that holds can hide an exhausted margin.