When the project baseline schedule is developed, most of the relationships used should be Finish-to-Start, FS. There is always the need for Start-to-Start, SS or Finish-to-Finish, FF relationships to model some sequences of work, but it’s best to break the work down enough to schedule with predominately FS relationships.
That said, far too often it seems that progress is not what was planned due to one reason or another. During the update process, assigning the actual dates and expected finishes to current activities pushes the schedule out. Sometimes only a day or so, but sometimes the schedule can push out weeks…..
How do we recover this lost time? How do we plan the remaining work to mitigate the late project finish? How do we keep from turning in a schedule update that the owner will immediately reject with the demand for a “Recovery Schedule”?
Often, there is a mix of activity duration reductions and resequencing of work.
If the parties responsible for the activities agree to the duration reductions and commit to supporting the schedule with additional resources or hours, this is usually not a problem. There may be work area size constraints that limit the effectiveness of more resources, or there may be logistical constraints that limit the amount of work which can be placed. But usually, adding resources or hours, in small quantities can work.
The trouble usually comes from resequencing the work. All too often, the recovery is achieved by taking several activities sequences with FS relationships and making the relationships SS with small lags. Basically, this is modeling the work to have each trade on top of the predecessor work’s trade. Rarely is this successful. What ends up happening is the work gets “stacked”. The work that couldn’t be completed when it was scheduled, with the resources available, is now magically supposed to be completed when other work is demanding more resources and there is less time to complete the work for that area.
Don’t get me wrong, limited resequencing of work is normal and can be done successfully. But it is not the cure-all for lack of progress.
So, how do we efficiently recover the lost time?
In reality, the scheduled finish date is only pushed out by lack of progress for work on the Critical (Longest) Path. The key is looking at the activities on the Critical Path and finding a way to work with durations and sequencing to shorten this path. This is an iterative process because the Critical Path will shift to the next Near Critical Path as you shorten the current Critical Path.
The thing to remember is not to let work not on the Critical or Near Critical Path sit. Work where you can when you can. But always make sure you’re making adequate progress for work on the Critical and Near Critical Path(s). If you do this, you won’t have to worry about recovering time!
I know many of you can offer additional comments and recommendations. I welcome your comments and input. My goal, as always, is to help our industry and help the projects we support….
I’d love to hear what you think!
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Paul Epperson CCM, PMP, PSP, PMI-SP