A predecessor is a task that determines when another task (a successor) can be scheduled. The default link type for all links between tasks is finish-to-start (FS).

The format for identifying a predecessor task in the Predecessors column is Task ID[Dependency Type][Lag duration or percent]. ID identifies the successor task's position in the task plan. The amount of lag time for the dependency (if a negative number) or lead time (if a positive number) is shown as a duration or a percent. For example, a predecessor task with a finish-to-start dependency and a lead time of 20% would be formatted as 7FS20%; a predecessor task with a finish-to-finish dependency and a lag of 10 days would be formatted as 6FF-10d. When a task has more than one dependency, a semi-colon is used to separate them. For example, 7FS20%;6FF-10d.