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In project management, float or slack is the amount of time that a task in a project network can be delayed without causing a delay to:
subsequent tasks ("free float")
project completion date ("total float")
the acceptable value must be positive, because if it is negative it indicates the amount of time that must be saved so that the project finish date is not delayed. Negative slack indicates that there is not enough time scheduled for the task and is usually caused by constraint dates.
Slack or Float provide flexibility in the project schedule. When leveraged properly, project managers can shift activities and resources to meet the project objectives and priorities. It is the amount of time an activity can be delayed without impacting other activities or the project end date and changes over the course of the project implementation.Slack and float are the same thing. They can be used interchangeably, so our discussion of slack and float will purposely use both. Once the concept is understood, it is more important to understand how to leverage slack time within projects.
Total Float: The total amount of time that a schedule activity may be delayed from its early start without delaying the project finish date, or violating a schedule constraint. Calculated using the critical path method technique and determining the difference between the early finish dates and late finish dates.
Free Float: The amount of time that a schedule activity can be delayed without delaying the early start date of any immediately following schedule activities. See also Total Float.
Slack time is the amount of time (hours, days, months or yrs) you can delay an activity without affecting the immediate linked successor activity.
It refers to the difference between the late and early start times of an activity.
Slack is the amount of time an activity may be delaed without delaying a succeeding activity or project finish time.
Acceptance value for slack or (float) should be positive value.
there is to type of slack also called float 1- free float it's the constrained time with the activity can delay without affecting the successor activity and it is less than Total float
2-total float
it's the constrained time with the activity can delay without affecting the Project and
can be calculated as follows
Total float=Early start of the activity-late start of the same activity
or
Total float=Early Finish of the activity-late Finish of the same activity
And you can identify the critical activities by its Total float (it have the minimum total float)
thx
And you can ask me if you want farther information :D
The slack time is the time within which you can change the starting time of a task without affecting the tasks dependent on its completion.
