Datasheet

Task Duration
Signing the good-bye card Three days
Ordering food One day
Reserving a room One hour
Buying a good-bye gift One day
The shortest task, reserving a room, takes only one hour. Assuming that plenty of rooms are avail-
able for holding the party, you can delay reserving the room until the last hour of the third day.
Delaying this task doesn’t cause any delay in holding the party — as long as you accomplish this
task by the end of the longest task, which is getting everyone to sign the good-bye card. Therefore,
the task of reserving a room isn’t on the critical path. However, you can’t delay the task of signing
the good-bye card, which is projected to take three days to accomplish, without delaying the party.
Therefore, the card-signing task is on the critical path. (Of course, this example is very simple; typ-
ically, a whole series of tasks that can’t afford delay form an entire critical path.)
The following points further define and clarify these concepts:
n
The critical path changes as the project progresses. Remember that a critical path is a
means of identifying tasks that have no leeway in their timing to ensure that they don’t
run late and affect your overall schedule. Knowing where your critical path tasks are at
any point during the project is crucial to staying on track. Figures 1.1 and 1.2 show the
same schedule — first with all tasks displayed and then filtered to show only the tasks
that are on the critical path.
See Chapter 7 to find out how to filter for only critical tasks and to see more informa-
tion about changing the view of your project.
n
Slack, also called float, is the amount of time that you can delay a task before that
task moves onto the critical path. In the preceding example, the one-hour-long task —
reserving a room — has slack. This task can slip a few hours, even a couple of days,
and the party will still happen on time. However, if you wait until the last half-hour of
the third day to reserve a room, that task will have used up its slack and it then moves
onto the critical path.
CROSS-REF
CROSS-REF
5
The Nature of Projects
1
06_009926 ch01.qxp 12/5/06 10:01 PM Page 5