backward pass
The Backward Pass answers the question, "What is the latest time Activity X can start without delaying the project?" To begin the backward pass, the scheduler starts at the end of the project and works forward. Typically the construction end date is used as the end date for the last CPM schedule’s activity. It is recommended that construction schedules actually include a "Finish Project" activity as their last activity.
Formal notation and calculation method for the Backward Pass is covered fully in the sections related to Arrow Diagramming and Precedence Diagramming.