According to the PMBOK® Guide, specifically within the Develop Schedule process and the Critical Path Method (CPM), the total float is a measure of schedule flexibility.
The Definition of Critical Path: The critical path is the sequence of activities that represents the longest path through a project, which determines the shortest possible project duration.
Total Float on the Critical Path: By definition, activities on the critical path have zero total float. This means there is no flexibility; any delay in a critical path activity will delay the project finish date.
Negative Float: Negative float occurs when a constraint on a finish date (a " Must Finish By " date) is violated. If the calculated early finish of the network is later than the required constraint date, the critical path will show negative float. This indicates that the project is already behind schedule relative to its constraints.
Positive Float: Positive float exists only on non-critical paths. These are sequences of activities that have " slack, " meaning they can be delayed without affecting the project completion date.
Comparison with other options:
A. Can be any number: While float can be many values, it is mathematically constrained by the network logic and project targets. It cannot be " any " number in the context of the critical path ' s definition.
B. Zero or positive: This describes a healthy, unconstrained schedule. However, it ignores the reality of negative float, which is a standard PMI concept for schedules that have missed their mandatory deadlines.
D. Depends on the calendar: While calendars (working vs. non-working days) affect the calculation of dates, the definition of the critical path float is a mathematical result of the forward and backward pass, not the calendar itself.
