PERT and CPM - by Saba (Mr.Ayesha)

PERT & CPM are techniques of project management, useful in the basic managerial function of planning, scheduling and controlling

PERT stands for “programme evaluation & review technique” whereas CPM is abbreviation of “critical path method”

If the project undertaken by project business houses are very large and take a number of years before commercial production starts, the techniques of PERT and CPM help greatly in completing the various jobs in the schedule. They minimize production delays, interruption and conflicts

PERT is sophisticated tool used in planning , scheduling and controlling large projects consisting of a number of activities independent of one another and with uncertain completion times. Following steps are required for using CPM and PERT for planning and scheduling

1. Each project consists of several independent jobs or activities. All these jobs or activities must be separately listed
2. Once the list of various activities is ready the order of precedence of the job has to be determined
3. The next step is to draw a picture or a graph which portrays each of these jobs and shows the predecessor and successor relation among them


Now the project of budgeting can be shown by way of a project graph network

1. Arrow connecting numbers 1 and 2 represent a job i.e. forecasting unit sales which would take 14 days
2. Numbers 2 and 4 represent job ‘b’ which will take 10 days and so on
3. It is seen that job ‘c’ is not dependent upon job b and therefore , the two jobs can be done simultaneously

Once we reduce the project to network of activities and events and we estimate activity duration, we are in position to determine the minimum time required for completion of whole project.

To do so we must find the longest path or sequence connecting the activities through the network. This is called “critical path” the longest path is the “critical path of the project”.

In our example there our two paths

One is connecting 1, 2, 4, &5 this will take 14+10+10= 34 days

The other path is connecting numbers 1,2,3,4 & 5; this path will take 14+7+4+10 = 35 days.

Obviously, the second path is the critical path and the project of budget presentation will take this much of time

Note: this time is shorter than the total time tested in under table 1 which will be 45 days. This is because job ‘b’ and ‘c’ can be done simultaneously

A good project network goes a long way in reducing cost.