Nothing really good happens at a milestone (read: also, gate). It's that simple (is there any need to read on?)
As long as were're doing rules of thumb, here's another:
- In other words, when you look at a schedule and you see a milestone, think immediately that there is a risk to shift right—that is, milestones are hazards to on-time performance.
- They are the first weakness to look at when assessing the schedule for risk
It’s common sense that the more independent an activity is, the more freedom of action there is. After all, there is minimum need to coordinate outcomes and processes if no one else is depending on your production. So, by corollary, dependencies (like those imposed at milestones) limit choices, and place constraints where there would not otherwise be inhibitions.
It’s no accident that milestones tend to shift to the right on the schedule. There is actually a mathematical explanation for this phenomenon that arises from the statistical behavior of risky activities.
For the statistician, there is no general formulation for the statistics of an intersection if the events are not independent. If they are not, then the only practical way to determine the performance of the intersection—in our case, the milestone—is to simulate the project by running many trials.
So, what's a PM to do? First to mission: Defeat all unfavorable forecasts! DDo not sit back and accept the inevitability of shifting right.
- You can reorganize the schedule logic
- You can put in buffers
- You can retool, retrain, re-resource to change the odds
- You can have a process for carrying deficiencies forward without impairing tthe critical path