Activity Duration
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?
- The total labor hours required to complete the task.
- The elapsed time, based on the project calendar, between the activity’s start and finish.
- The amount of time a resource is assigned to the activity.
- 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.
