Type
The Type field is a dropdown list containing the types of predecessor relationships a task can have with another task. The available options include the following (in each case, assume Task2 is being defined as dependent on Task1):
Finish-to-Start - Task 1 must finish before Task 2 can start.
Start-to-Start - Task 1 and Task 2 can start at the same time.
Finish-to-Finish - Task 1 and Task 2 can finish at the same time.
Start-to-Finish - Task 2 cannot finish until the start of Task 1.
To illustrate the various relationships, take the following example WBS where each of the sub-tasks are dependent on the parent Task 1 (having each of the 4 predecessor types).
Task 1 is a task that ends on June 27, 2012 and each of the sub-tasks are defined as having a 2 day duration. Because each of the sub-tasks are defined as having Task 1 as their predecessor, the date ranges for these sub-tasks are all derived (that is, you cannot manually manipulate them). Making any changes to the Task 1 date range will cause the system to automatically recalculate the dates for the dependent sub-tasks.
Finish-to-Start - Task 1 must finish before Task 1.1 can start, thus Task 1.1 has a begin date one business day after the Task 1 end date and an end date derived based on the task's duration.
Start-to-Start - Task 1 and Task 1.2 can start at the same time, thus Task 1.2 will have a derived begin date equal to the Task 1 begin date and an end date derived based on the task's duration.
Finish-to-Finish - Task 1 and Task 1.3 can finish at the same time, thus Task 1.3 will have a derived finish date equal to the Task 1 end date, and the Task 1.3 begin date will be derived prior to that (depending on that tasks duration).
Start-to-Finish - Task 1.4 cannot finish until the start of Task 1, thus Task 1.4 will have an end date equal to Task 1's begin date, and the Task 1.4 begin date will be derived prior to that (depending on that tasks duration).