Data Type Duration
Entry Type Calculated
Description The Start Slack field contains the duration between the Early Start and Late Start dates. The smaller of the start slack and finish slack amounts determines the amount of free slack available, that is, the amount of time a task can be delayed without affecting the start date of a successor task or the project finish date.
How Calculated Start slack is the duration that represents the difference between the early start and late start dates. The early start is the earliest date that a task could possibly start. Likewise, the Late Start field contains the latest date that a task can start without delaying the finish of the project. Microsoft Office Project calculates the start slack as follows:
Start Slack = Late Start - Early Start
Best Uses Add the Start Slack and Finish Slack fields to any task view when you want to review how free slack was calculated.
Example You are reviewing free slack in your schedule and want to see more details about how it was calculated. You add the Start Slack and Finish Slack fields to the task sheet and analyze the durations.
Remarks If a task has an actual start date and a deadline, the start slack is 0 and the finish slack is the difference between the task's finish date and deadline date.