Uses of slacks and floats in PERT and CPM

Uses of slacks and floats in PERT and CPM. (Apr 2006)

Slacks:            Slacks are for events. Slacks of all critical events are zero. Slack is the difference in Earliest occurrence time and Latest occurrence time for the event. It represents the margin by which the event occurrence can be delayed.

Floats: Floats are for activities. Total, Free, Independent and Interfering floats are types of floats. Floats represent the margin by which activity start times can be delayed without affecting project completion time.

Floats for critical activities are zero. They can not be delayed by any margin.