TASK DEPENDENCIES: FS / SS / FF / SF IN MS PROJECT PROFESSIONAL

Task Dependencies : To Define the Relationships Between Tasks 

Predecessor :

A predecessor is a task whose start or finish date determines the start or finish date of its successor task.

Successor : 

A successor is a task whose start or finish date is driven by its predecessor task.

The nature of the relationship between a predecessor task and a successor task determines the type of task dependency to use. We can use FOUR types of task dependencies.

1. Finish - To  - Start    [ FS ]
2. Start   - To  - Start    [ SS ]
3. Finish - To  - Finish  [ FF ]
4. Start   - To -  Finish  [ SF ]

For Example, if we have Two tasks, Task 1 and Task 2 in our Testing Project , we can define all the 4 relationships by following steps:

• If Task 2 is having Predecessor as Task 1, double Click on Task 2 
• Task Information window will appear
• In the Predecessor section, select the option from Type Drop down list ( FS / SS / FF / SF)
• Ok

A. Finish - to  - Start Dependency

Task 1 must finish before Task 2 can start. This is the By Default  Dependency created and very commonly used Relationship in Project.

 B. Start - to  - Start Dependency

 Task 1 and Task 2 must start at the same time.

Benefit of using SS Dependency

Overlapping work helps to reduce the overall duration of a project. In our Testing Project, as we can see from the Total Duration of the Project, we Save 3 days’ work by using SS Dependency.

C. Finish - to  - Finish Dependency

Task 1 and Task 2 must finish at the same time.

FF dependencies also reduce the overall amount of time in Project, same as SS Dependency.

• If Task 1 will take 5 days to complete, and Task 2 will take 3 days to complete, with FS dependency the overall duration of the two tasks is 8 days.
• If  we set an FF dependency, the overall duration of the two tasks is only 5 days.

D. Start - to  - Finish Dependency

Task 2 cannot finish until the start of Task 1.  This is VERY RARE scenario of Task in any type of Project.

As we can see Task 2 has been moved from his scheduled Start date due to SF Relationship. 

As an Example,  A particular task needs to finish before a milestone or project finish date, but it doesn't matter exactly when and we don't want a finish  it late to affect the regular task in that scenario we can use SF dependency