HKSM

The total elapsed time, measured using the project calendar, from when a scheduled activity starts until it finishes.

Key Points

• Measured in calendar units (e.g., days or weeks) according to the applicable project calendar.
• Represents elapsed time from start to finish, which can include waiting or idle periods.
• Different from effort; effort is labor hours, while duration is calendar time.
• Used to develop the schedule, analyze the critical path, and set realistic dates.

Example

A task to pour concrete involves 4 hours of work plus 48 hours of curing. If started Monday morning on a 7-day calendar, the activity finishes Wednesday morning and the activity duration is 2 days, even though the actual work took only 4 hours.

PMP Example Question

Which statement best describes activity duration?

1. The total labor hours required to complete the task.
2. The elapsed time, based on the project calendar, between the activity’s start and finish.
3. The amount of time a resource is assigned to the activity.
4. The sum of the lengths of all network paths in the schedule.

Correct Answer: B — Elapsed calendar time between start and finish

Explanation: Activity duration is the calendar-based elapsed time from start to finish. Effort (A) is labor hours, resource assignment (C) is not necessarily duration, and (D) is unrelated.