Most monthly reports show a critical path. Fewer show the driving path: the chain of activities that is actually setting the finish date on this data date. They should be the same. Often they are not, and the difference is where surprises come from.
Step 1: confirm the data date
Everything before the data date should be actual. Everything after should be forecast. If there are incomplete activities in the past or actuals in the future, stop. The path you are about to read is not real.
Step 2: trace back from the finish
Start at the contract finish or the milestone you care about. Follow its driving predecessor, then that activity’s driving predecessor, back to the data date. In P6 you can trace driving relationships directly. Write the chain down.
Step 3: compare it with last month
If the path changed, ask why. A new path driving the finish is not a problem in itself. A path that changed because logic was deleted, a constraint was added or a duration was cut is a problem worth naming.
Step 4: read the near-critical paths
List the paths within a small number of days of the driving path. The one with ten days of float that lost three this month is the one that will surprise you next quarter.
Step 5: test it against the field
Take the first three activities on the driving path to the superintendent. Are those crews actually working? Is the material on site? If the field says something else is holding the job, the schedule is missing logic.
Step 6: say what it means
- What is driving the finish this month, in one sentence.
- How many days of float the nearest competing path has left.
- Which decision, if made this month, would protect the date.
See a driving path recalculate live in Schedule Studio, or ask us for critical path analysis on your current update.
