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Float (project management)
Encyclopedia
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:
An activity on critical path has "zero free float", but an activity that has zero free float may not be on the critical path.
Total float is associated with the path. If a project network chart/diagram has 4 non-critical paths then that project would have 4 total float values. The total float of a path is the combined free float values of all activities in a path.
The total float represents the schedule flexibility and can also be measured by subtracting early dates from late dates of path completion. Float is core to critical path method
.
Some of these activities can run concurrently e.g. obtaining the glass, obtaining the putty, choosing the paint etc., while others are consecutive e.g. the paint cannot be bought until it has been chosen, the new putty cannot be painted until the window is installed and the new putty has set. Delaying the acquisition of the glass is likely to delay the entire project - this activity will be on the critical path and have no float, of any sort, attached to it and hence it is a 'critical activity'. A relatively short delay in the purchase of the paint may not automatically hold up the entire project as there is still some waiting time for the new putty to dry before it can be painted anyway - there will be some 'free float' attached to the activity of purchasing the paint and hence it is not a critical activity. However a delay in choosing the paint in turn inevitably delays buying the paint which, although it may not subsequently mean any delay to the entire project, does mean that choosing the paint has no 'free float' attached to it - despite having no free float of its own the choosing of the paint is involved with a path through the network which does have 'total float'.
Project management
Project management is the discipline of planning, organizing, securing, and managing resources to achieve specific goals. A project is a temporary endeavor with a defined beginning and end , undertaken to meet unique goals and objectives, typically to bring about beneficial change or added value...
, float or slack is the amount of time that a task in a project network
Project network
A project network is a graph depicting the sequence in which a project's terminal elements are to be completed by showing terminal elements and their dependencies....
can be delayed without causing a delay to:
- subsequent tasks ("free float")
- project completion date ("total float")
An activity on critical path has "zero free float", but an activity that has zero free float may not be on the critical path.
Total float is associated with the path. If a project network chart/diagram has 4 non-critical paths then that project would have 4 total float values. The total float of a path is the combined free float values of all activities in a path.
The total float represents the schedule flexibility and can also be measured by subtracting early dates from late dates of path completion. Float is core to critical path method
Critical path method
The critical path method is an algorithm for scheduling a set of project activities. It is an important tool for effective project management.-History:...
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Example
Consider the process of replacing a broken pane of glass in the window of your home. There are various component activities involved in the project as a whole; obtaining the glass and putty, installing the new glass, choosing the paint, obtaining a tin of paint, painting the new putty once it has set, wiping the new glass free of finger smears etc etc.Some of these activities can run concurrently e.g. obtaining the glass, obtaining the putty, choosing the paint etc., while others are consecutive e.g. the paint cannot be bought until it has been chosen, the new putty cannot be painted until the window is installed and the new putty has set. Delaying the acquisition of the glass is likely to delay the entire project - this activity will be on the critical path and have no float, of any sort, attached to it and hence it is a 'critical activity'. A relatively short delay in the purchase of the paint may not automatically hold up the entire project as there is still some waiting time for the new putty to dry before it can be painted anyway - there will be some 'free float' attached to the activity of purchasing the paint and hence it is not a critical activity. However a delay in choosing the paint in turn inevitably delays buying the paint which, although it may not subsequently mean any delay to the entire project, does mean that choosing the paint has no 'free float' attached to it - despite having no free float of its own the choosing of the paint is involved with a path through the network which does have 'total float'.