Dennis DavisConsultant| Davis ConsultingAntioch, Ca, United States
I'm trying to shorten the durations of my tasks in MS Project. What I have done is to link my summary tasks by the default finish to start and that, of course, caused my durations to grow immensely. So the next thing I did was to link the sub-tasks within each summary task but I used a Finish to finish relationship. It shortened the durations nicely, but I'm worried that I'm setting up artificial durations. Are there any negative results to doing it this way or is there a better method? By way of example:
Summary task 1 - ABC
subtask 1 - 123
subtask 2 - 456
Summary task 2 - DEF
subtask 1 - 789
subtask 2 - 10
Summary tasks 1&2 linked via FS
Subtask123 linked to 456 via FF
Subtask 789 linked to 10 via FF.
etc.
Thanks in advance for any help from a first time writer to this forum. Saving Changes...
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Anonymous
Will the same resource be working the tasks with the FF dependencies? Is there a real dependency between the tasks or are you just trying to make it fit? If you change the tasks to FF, do you overallocate the resource? I typically do not use a dependency of any kind uless there is a real, physical reason to do so (i.e. roof can't go on until the frame is up). Let us know a few more details, and maybe we can help Saving Changes...
Darrell MarkhamSr. IT Project Manager| Tyler TechnologiesBrentwood, Ca, United States
Dennis,
I never link summary tasks with any type of dependencies (you also cannot use FF or SF on summary tasks); it also wreaks havoc with the Critical Path. You should be creating a nice little module with each deliverable in your schedule. It should have a summary task, all of the detail tasks and end with a milestone. The detail tasks and milestone should all be linked with dependencies in a logical manner. You should always try to use As-Soon-As-Possible (ASAP) constraints when using forward scheduling (the default in MS project). This constraint can move in both directions and is more of a “Tendency” than an actual constraint that restricts movement. This module should be the building block for your entire schedule. Once you have all of the deliverables properly modeled you can link them in the necessary logical order without using the summary tasks. This is where the network diagram is very handy, you can quickly see the network logical and whether the network of dependencies is complete. You also do not want to assign resources to a summary task, doing so assigns all of the deliverable work to that resource. And of course you want to be sure you have properly leveled the resources within your schedule as mentioned by Rich. There is such a thing as the Resource Critical Path, especially if your company is resource constrained.
There are a number of methods used to optimize schedules. When optimizing for time I like using the filter function and grouping function to identify my longest critical path tasks, they offer the most potential for the biggest reduction in time. This is why I believe in using dependencies to develop a completed Critical Path in my schedule. Once I have done this, I filter on “critical tasks” and group on “duration” to see which tasks are the longest ones driving the completion date of the schedule.
The problem is that you're using the dependencies merely for aesthetics. A task that is FS takes longer than a FF simply because of what it means. You can’t start Task #2 until Task #1 is complete; this is a finish to start relation. Good examples are normally physical ones; you can’t put up the wall paper until you have walls. A FF task means, you can’t finish Task #2 until Task #1 is finished. This means that you can work on Task #1 and Task #2 simultaneously. You should look at all the tasks on your project and determine which fall into what category. As the other posters have suggested, not all tasks will need dependencies, you only want to put dependencies where they are applicable. Saving Changes...
Alan Boudreau PMPSenior Project Manager| University Support Services, LLCGreat River, Ny, United States
Another option is to use Lag and Lead times where appropriate, i.e. task 2 starts 5 days before the finish of task 1 -
'1FS-5d'. This allows a second task to start prior to the actual finish of a previous task and assumes that some, but not all, of the previous task is required before the subsequent task starts. Saving Changes...
Dennis DavisConsultant| Davis ConsultingAntioch, Ca, United States
Thanks for the responses. I've actually gone back to my network diagram and re-worked the tasks using Alan's idea of lead and lag times. It took a bit of work but the result was worth the effort. Thanks again. Saving Changes...
