Slack is defined as which of the following expressions?

Slack is defined as which of the following expressions?

• A. Slack equals LS - ES or LF - EF
• B. Slack equals ES - LS or EF - LF
• C. Slack equals the sum of all delays
• D. Slack is the time between project start and finish

Answer: (A)

Slack is the amount of time a task can be delayed without delaying the project’s finish. In CPM, you can measure this by looking at the difference between the latest and earliest start times (LS − ES) or the difference between the latest and earliest finish times (LF − EF). Those two expressions always give the same slack value for a task. If a task has zero slack, it sits on the critical path and has no scheduling flexibility; otherwise, the positive slack shows how much delay is tolerable without impacting the overall project end date. The other options don’t describe this idea: ES − LS would be the reverse and isn’t used as the allowable delay, the sum of all delays isn’t how slack is defined, and the time between project start and finish is the total project duration, not slack.

Slack is the amount of time a task can be delayed without delaying the project’s finish. In CPM, you can measure this by looking at the difference between the latest and earliest start times (LS − ES) or the difference between the latest and earliest finish times (LF − EF). Those two expressions always give the same slack value for a task. If a task has zero slack, it sits on the critical path and has no scheduling flexibility; otherwise, the positive slack shows how much delay is tolerable without impacting the overall project end date. The other options don’t describe this idea: ES − LS would be the reverse and isn’t used as the allowable delay, the sum of all delays isn’t how slack is defined, and the time between project start and finish is the total project duration, not slack.