Page 512 - Using MIS

480 Chapter 12 Information Systems Development

is completed. Other task dependencies are also shown; you can learn about them in a project
management class.
The critical path is the sequence of activities that determine the earliest date by which the
project can be completed. Reflect for a moment on that statement: The earliest date is the date
determined by considering the longest path through the network of activities. Paying attention
to task dependencies, the planner will compress the tasks as much as possible. Those tasks that
cannot be further compressed lie on the critical path. Microsoft Project and other project-plan-
ning applications can readily identify critical path tasks.
Figure 12-17 shows the tasks on the critical path in red. Consider the first part of the WBS.
The project planner specified that task 4 cannot begin until 2 days before task 3 ends. (That’s the
meaning of the red arrow emerging from task 3.) Neither task 5 nor task 8 can begin until task
4 is completed. Task 8 will take longer than tasks 5 and 6, and so task 8—not tasks 5 or 6—is on
the critical path. Thus, the critical path to this point is tasks 3, 4, and 8. You can trace the critical
path through the rest of the WBS by following the tasks shown in red, though the entire WBS and
critical path are not shown.
Using Microsoft Project or a similar product, it is possible to assign personnel to tasks and
to stipulate the percentage of time that each person devotes to a task. Figure 12-18 shows a
Gantt chart for which this has been done. The notation means that Eleanore works only 25 per-
cent of the time on task 3; Lynda and Richard work full time. Additionally, one can assign costs
to personnel and compute a labor budget for each task and for the overall WBS. One can assign
resources to tasks and use Microsoft Project to detect and prevent two tasks from using the same
resources. Resource costs can be assigned and summed as well.
Managers can use the critical path to perform critical path analysis. First, note that if a task is
on the critical path, and if that task runs late, the project will be late. Hence, tasks on the critical
path cannot be allowed to run late if the project is to be delivered on time. Second, tasks not on the
critical path can run late to the point at which they would become part of the critical path. Hence,
up to a point, resources can be taken from noncritical path tasks to shorten tasks on the critical
path. Critical path analysis is the process by which project managers compress the schedule by
moving resources, typically people, from noncritical path tasks onto critical path tasks.

Figure 12-18
Gantt Chart with Resources
(People) Assigned