- Duration is the length of
time that you would use
for an activity when you
place it on your project
schedule. - Duration is derived by
considering the effort
required to complete an
activity, then making
appropriate adjust
ments for: - The quantity of
resources assigned to
work on the activity (and how efficiently they can work
together at the same time) - The general availability of the resources (half-time?
quarter-time? 10%?) - Specific periods of inactivity or unavailability (vaca-
tions, site shutdowns) - Weekends, holidays
- Number of hours assumed in each work day
Although duration appears to be a calculated quantity, you
should think of it as more of a negotiated figure and a kind of
“meeting of the minds” than as a calculation. When you and a
given task performer agree on a duration for an activity, it
almost represents a contractual relationship—the task per-
former is promising to finish the task within a window of time
and you are accepting that estimate.
Converting the Network Diagram to a Project Control Schedule
In the seven-step process briefly described above, steps 4-6
represent an iterative process that consists of combining the
logical relationships you developed through network diagram-
ming, your estimated activity durations, and any known con-
straints. The final result will be the project control schedule.
Think of a control schedule as a logic-based bar chart that has
128 Project Management
You Need Both
In order to properly
manage your project,
you will need to understand, quantify,
and track both effort and duration.
Since effort represents the time peo-
ple are charging to your project, it
relates directly to cost estimating,
budget preparation, and cost control.
Duration relates directly to schedule
estimating, schedule creation, and
schedule control.