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Teresa Canive
Written by Teresa Canive

What is the Slack of an activity?

Take into account the slack of activities if you don´t want to delay the entire project.


The float or slack of an activity is basically the date constrains within we can plan our activity without affecting the overall length of the project, or any of the defined date constrains. This constrains could be defined by deliverables or milestones for example.

María explains it in less than two minutes in this video


Activity slack is defined by its dependencies, its duration and also constrain dates assigned to other activities.

Activities with no float (or slack)


As you can see in the picture. Design Context depends on Design Objetives. For this reason Sinnaps placed them one after the other. In this case there are no other dependencies or date constrains to any of these activities so they have been placed by Sinnaps one after the other. Also because they are placed in the top lane, we now see that they are both in the Critical Path of our project.

This is why we know that the delay of any of these activities could affect the overall time of the project. 

NOTE: The gray area in the background is dining the slack limits of our activity. This is why we will not be able to reschedule the activity in any of those dates.


Planning activities with slack


However, following the same example. We do have slack to de right side of the activity. This means that because we don't have any date constrains to the right, we can reposition to later days. Imagine that we suspect that Design Objetives can be delayed a couple of days. No problem! Because there is no slack to that side, we can cut short Design Context and reposition it adding a date constrain. This way we force it to start a few days later. 

In this example we added 2 extra days to the planning just in case. By doing so, Sinnaps will reposition all affected activities instantly.

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