Which statement about float in scheduling is correct?

Which statement about float in scheduling is correct?

• A. Float exists only on non-critical tasks.
• B. Free float is the time an activity can be delayed without delaying any successor.
• C. Total float is the budget reserve for an activity.
• D. Float must always be zero for milestones.

Answer: (B)

In scheduling, float (slack) measures how much flexibility you have before the plan is affected. There are different types, with free float being the one that specifically looks at successors. Free float is the amount of time an activity can be delayed without delaying the earliest start of any of its immediate successors. Put simply, it’s the gap between when an activity can finish and when its successors must start to stay on track. For example, if an activity can finish by day 6 but its earliest successor must start at day 9, you have 3 days of free float. You could slip those 3 days without pushing any successor start times. This is distinct from total float, which is how long you can delay an activity without delaying the project’s finish date. Total float can be equal to or greater than free float, depending on how delays ripple through the network. The other statements aren’t correct because: float isn’t limited to non-critical tasks—critical activities can have zero total float, though they might still have some free float in certain network structures; total float isn’t a budget reserve for cost—it’s time slack; and milestones aren’t guaranteed to have zero float—their scheduling can still allow delays around them depending on the network and dependencies.

In scheduling, float (slack) measures how much flexibility you have before the plan is affected. There are different types, with free float being the one that specifically looks at successors.

Free float is the amount of time an activity can be delayed without delaying the earliest start of any of its immediate successors. Put simply, it’s the gap between when an activity can finish and when its successors must start to stay on track. For example, if an activity can finish by day 6 but its earliest successor must start at day 9, you have 3 days of free float. You could slip those 3 days without pushing any successor start times.

This is distinct from total float, which is how long you can delay an activity without delaying the project’s finish date. Total float can be equal to or greater than free float, depending on how delays ripple through the network.

The other statements aren’t correct because: float isn’t limited to non-critical tasks—critical activities can have zero total float, though they might still have some free float in certain network structures; total float isn’t a budget reserve for cost—it’s time slack; and milestones aren’t guaranteed to have zero float—their scheduling can still allow delays around them depending on the network and dependencies.