Slack

The amount of time a task can slip before it affects another task’s dates or the project finish date. Free slack is the amount of time a task can slip before it delays another task. Total slack is the amount of time a task can slip before it delays the project finish date. When the total slack is negative, the task duration is too long for its successor to begin on the date required by a constraint. (Wimincken.com PM Glossary)

Other Definitions

Slack – In PERT ,the scheduling flexibility available for an activity; equivalent to total float in CPM (CPM in Construction Management by James O’Brien 2nd Edition)

Slack – Term used in PERT for float .(Wideman Comparative Glossary of Common Project Management Terms v2.1 )

Slack – Free time in a critical path schedule resulting form paths shorter than the the critical path. (see float) (Critical Chain Project Management by Lawrence P. Leach)

J. Jerrald Hayes

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