S

schedule

see project schedule.

schedule analysis

see network analysis.

schedule performance index (SPI)

the ratio of work that is performed to work that is scheduled (BCWP/BCWS). See earned value.

schedule variance

(1) any difference between the scheduled completion of an activity and the actual completion of that activity.

(2) in earned value, BCWP less BCWS.

scheduled finish date (SF)

the date when the activity is scheduled to be completed using the resource-constrained scheduling process.

scheduled start date (SS)

the date when the activity is scheduled to begin using the resource-constrained scheduling process. This date is equal to or greater than the early start date.

slack

term used in PERT for float (see also total float).

subtask

an activity that is contained within a supertask.

successor activity

any activity that exists on a common path with the activity in question and occurs after the activity in question.

supertask

an aggregate or summary activity that contains one or more activities (subtasks) such that no subtask can begin until the supertask has begun. The supertask cannot end until all of the subtasks have ended.