Duration
The count of working time units needed to finish an activity or WBS element, typically measured in hours, days, or weeks. It is different from effort, which is the amount of labor applied.
Key Points
- Duration measures elapsed working time on the project and resource calendars, not the total labor.
- It applies to an activity or a WBS component and is shown in hours, days, or weeks.
- Duration can change with resource availability and allocation; effort may stay the same while duration shortens or lengthens.
- Nonworking time (weekends, holidays) is excluded based on calendars; this affects finish dates.
Example
A task needs 40 hours of effort. With one full-time resource (8 hours/day), the duration is 5 working days. If two full-time resources share the work, the effort is still 40 hours, but duration can compress to about 2.5 working days, assuming the work is divisible.
PMP Example Question
Which statement best describes duration?
- The total labor required for an activity, measured in person-hours.
- The number of working time units to complete an activity, based on calendars.
- The total calendar days from start to finish, including weekends and holidays.
- The amount of time a resource is assigned at any utilization level.
Correct Answer: B — The number of working time units to complete an activity
Explanation: Duration is the required working time to finish an activity or WBS component, typically in hours, days, or weeks, and is distinct from effort (labor).
