Categorized | Management

Understanding Project Dependencies- Why They Are Vital To Your Project

Project dependencies are the relationships of tasks to other tasks that determine the sequence in which they need to be done, with the relationships driving the schedule for the entire project. Project planning and management methodologies listing and scheduling tasks such as the Work Breakdown Structure (WBS) and the Critical Path Schedule (CPS) are highly dependent on the understanding project dependencies and how they work.

Why You Need To Understand Project Dependencies
Most, if not all, projects are clearly task-oriented and tied to scheduling. Ordering these tasks in order to follow set timelines to ensure project completion within the allowable period set is the most basic reason that a project manager needs to understand project dependencies. Since most tasks required to complete deliverables are often based on other tasks being completed, this helps prevent unnecessary delays, waiting periods, and imposes the sense of urgency all task teams need for a project to be completed.

Four Project Dependencies And Their Implications On The Schedule

Finish to Start (FS) Dependencies. The most common dependency, this is a schedule wherein the second task in workflow cannot begin until the first task finishes. A delay in the first task will certainly cause delays on the dependent tasks. If starting other tasks are also dependent on the subsequent task to be finished, this can cause bottlenecks in the schedule. Tasks that need to be finished for other tasks to start are often necessarily placed in the critical path schedule. Common examples of this dependency are projects wherein completed deliverables in certain tasks serve as the starting materials or equipment for subsequent tasks.

Start to Start (SS) Dependencies. This is when the second task in the relationship cannot be started until after the other task in the relationship is begun. While start-to-start dependencies do not require that both tasks are began at exactly the same time, it is necessary for the first task to be started in order to begin work on the dependent task. Often coming into play in process-based tasks, one example is when

Finish to Finish (FF) Dependences. This is when a task cannot be finished until another one is completed. As with SS dependencies, FF dependencies do not require that both tasks be finished simultaneously. They simply require that the completion of one task in order for the dependent task to finish. In the case of an FF dependency, the dependent task can finish any time after the first task is completed.

Start to Finish (SF) Dependencies. A little trickier than the other three types of dependencies, this is when the dependent task in the relationship cannot be completed until the first task starts. The dependent task, however, can finish any time after the first task is started.

Constraints Arranging Tasks In A List
Listing of tasks (such as in a war room wall posting) is always easier if begun using finish-to-start dependencies relationship and ‘as soon as possible’ time constraints. While this will often result in a longer than normal schedule, this dependency type is the easiest relationship for team members to see and understand. The longer schedule is not also always necessarily bad– it allows the schedule more ‘slack’ in the beginning, and the project manager can later on adjust dependencies to shrink the timetable for the overall schedule when necessary.

Leave a Reply