Page 124 - DMGT302_FUNDAMENTALS_OF_PROJECT_MANAGEMENT

Unit 7: Project Scheduling

Framework for PERT and CPM Notes

Essentially, there are six steps which are common to both the techniques. The procedure is listed
below:
1. Define the Project and all of it’s significant activities or tasks. The Project (made up of
several tasks) should have only a single start activity and a single finish activity.
2. Develop the relationships among the activities. Decide which activities must precede and
which must follow others.
3. Draw the “Network” connecting all the activities. Each Activity should have unique event
numbers. Dummy arrows are used where required to avoid giving the same numbering
to two activities.
4. Assign time and/or cost estimates to each activity.
5. Compute the longest time path through the network. This is called the critical path.
6. Use the Network to help plan, schedule, monitor and control the project. The Key Concept
used by CPM/PERT is that a small set of activities, which make up the longest path
through the activity network control the entire project. If these “critical” activities could
be identified and assigned to responsible persons, management resources could be
optimally used by concentrating on the few activities which determine the fate of the
entire project.
Non-critical activities can be replanned, rescheduled and resources for them can be reallocated
flexibly, without affecting the whole project. Five useful questions to ask when preparing an
activity network are:
1. Is this a Start Activity?
2. Is this a Finish Activity?
3. What Activity Precedes this?
4. What Activity Follows this?
5. What Activity is Concurrent with this?
Some activities are serially linked. The second activity can begin only after the first activity is
completed. In certain cases, the activities are concurrent, because they are independent of each
other and can start simultaneously. This is especially the case in organisations which have
supervisory resources so that work can be delegated to various departments which will be
responsible for the activities and their completion as planned.
When work is delegated like this, the need for constant feedback and coordination becomes an
important senior management preoccupation.
Drawing the CPM/PERT Network

Each activity (or sub-project) in a PERT/CPM Network is represented by an arrow symbol. Each
activity is preceded and succeeded by an event, represented as a circle and numbered.

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