Project scheduling glossary
The terms behind every schedule, each defined in a sentence or two and shown on a small worked example calculated by Depentra's scheduling engine.
Dependencies
Project dependency
A project dependency is a link between two tasks that controls when one of them can start or finish, based on the other.
Predecessor and successor
In a project schedule, a predecessor is a task that another task depends on, and a successor is the task that depends on it.
Finish-to-start (FS)
A finish-to-start (FS) dependency means the successor cannot start until its predecessor has finished.
Start-to-start (SS)
A start-to-start (SS) dependency means the successor cannot start until its predecessor has started.
Finish-to-finish (FF)
A finish-to-finish (FF) dependency means the successor cannot finish until its predecessor has finished.
Start-to-finish (SF)
A start-to-finish (SF) dependency means the successor cannot finish until its predecessor has started.
Lag
Lag is a waiting time added to a dependency: the successor waits that many days after the link would otherwise allow it to start or finish.
Lead
Lead is negative lag: it lets the successor start before the dependency would otherwise allow, so the two tasks overlap.
Schedule analysis
Critical path
The critical path is the longest chain of dependent tasks through a project.
Total float
Total float, also called slack, is the number of days a task can slip without moving the project's finish date.
Free float
Free float is the number of days a task can slip without delaying the earliest start of any task that depends on it.
Delay propagation
Delay propagation is the way a delay on one task moves the tasks that depend on it, directly or through a chain, until slack in the plan absorbs it or it reaches the project's finish date.
Planning and control
Schedule baseline
A schedule baseline is a saved copy of the approved schedule, the dates a project committed to, that progress and forecasts are measured against.
Milestone
A milestone is a point in a schedule with no duration that marks an event, such as a sign-off, a delivery or a go-live, rather than a piece of work.
Cross-project dependency
A cross-project dependency is a link between tasks in two different projects, where work in one project waits on work in another.
Go deeper
The guides work the methods through by hand; the free simulator runs them on your own plan.