Tasks With Negative Slack (Also Called Negative Float)
What gets flagged by the Audit
A Task or Milestone with a value less than zero in the Microsoft Project column named Total Slack.
Why does it matter if items in the project have Negative Slack?
Negative Slack (Float) means that tasks do not start or finish in time to meet one or more critical date in the project.
What Else to Consider
The 14 Point Assessment tests for "Negative Float"
Negative Float: Total number of activities that are incomplete and have float less than zero working days.
Resolving Negative Slack
Perform the Audit and Click on each item in the resulting tasks list to go to the offending task. You can also click Filter for Items Below to display tasks with audit issues and record the offending condition in the Integrity Note log field.
The status, duration, predecessors & successors of tasks with negative slack should be carefully examined for opportunities to mitigate or eliminate the causes of the condition. Resolving negative slack may include decreasing the duration of tasks, eliminating unnecessary tasks and changing the predecessor and successor tasks or dependency types . The SSI Trace Tools can help identify the tasks and workflow that are the root cause of negative slack in a project.
What Does Negative Float Looks Like in a Project?
Example 1 - Task Finish does not support a key due date or deliverable in the project
In this example, The combined duration of the sequence of tasks (Task 1 and Task 2) does not support the due date for Milestone C. This example is simplified to show a direct relationship between the tasks and the due date. In most cases, negative slack flows through many layers of task dependencies. The SSI Critical Path Method analysis tool is a good way to find and resolve negative slack in a project.
Example 2 - Negative Slack condition resolved
This example shows one possible solution to resolve the negative slack condition shown in example 1. In this case, Task 1 and Task 2 are now done in parallel rather than in series. Since working in parallel shortens the overall duration required to perform both tasks, they now finish 1 day earlier than the due date for Milestone C and the negative slack is removed.
