Wysocki (2012, pp.204) identified dependencies as “a relationship that exists between pairs of tasks”. In projects planning, the work breakdown structure (WBS) forms the basis for determination of tasks and their dependencies. Once the WBS is established - often in diagrammatical form, tasks and their dependencies can be easily mapped in the project network diagram. Project network diagram graphically represents project commencement and ending with tasks, activities, various paths to attaining deliverables, etc, in between.
In Understanding Task Dependencies in Project Management (Project Insight, n.d) four types of task dependencies were identified with examples of each given as follows using “P” (predecessor) and “S” (successor) to denote tasks; -
|Finish to Start|[pic] |Predecessor must finish before Successor can start. [Land |
|(FS) | |must be purchased before road building can start] |
|Start to Start |[pic] |Predecessor must start before Successor can start. [Road |
|(SS) | |excavating must start before Asphalt can be laid] |
|Finish to |[pic] |Predecessor must finish before Successor can finish. |
|Finish (FF) | |[Laying Asphalt must be complete before line painting can |
| | |be completed] |
|Start to Finish|[pic] |Predecessor must start before Successor can finish. [Road |
|(SF) | |excavating must start before line painting can be |
| | |completed] |
Task dependency becomes very important as it establishes the relationship between tasks