Planning, Scheduling and Controlling are three important functions of management. Planning involves the formulation of objectives and goals that are subsequently translated into Specific plans and projects. Scheduling is concerned about the implementation of activities necessary to achieve the laid down plans. The function of control is to institute a mechanism that can trigger a warning signal if actual performance is deviating (in terms of time, cost and some other measures of effectiveness) from the plan. If such a deviation is unacceptable to the concerned manager, he will be required to take corrective action to bring performance in conformity with the plans. The PERT and CPM models are extremely useful for the purpose of planning, scheduling and controlling the progress and completion of large and complex projects or for carrying out the analysis of these three managerial functions. Before we describe the basic concepts used in the construction and analysis of these models, let us first understand the meaning of a project.
What is a project?
A project can be defined as a set of large number of activities or jobs that are performed in a certain sequence determined logically or technologically and it has to be completed within (i) a specified time, (ii) a specified cost and (iii) meeting the performance standards. Examples of a project from fairly diverse fields are given below:
1.Introducing a new product in the market.
2. Construction of a new bridge over a river or construction of a 25 storied building, 3. Executing a large and complex order on jobbing production. 4. Sending a spacecraft to the mars.
GENERAL FRAMEWORK OF PERT/CPM
A network is a graphical representation of a project, depicting the flow as well as the sequence of well-defined activities and events. Developed during the 1950s, both CPM (Critical Path Method) and PERT (Programme Evaluation and Review Technique) are network techniques/models. The network approach helps project managers in planning,
Scheduling and controlling. As a planning tool it helps the manager to estimate the requirements of resources viz., materials, equipment, manpower, cost and time for each activity or tasks of the project. This approach cannot make decisions by its own. It only provide additional information to executives to facilitate decision making process. Also it does not provide solution to every management problem. It certainly helps in identification of those activities, jobs or events which control the completion of the project.
The working methodology of critical path analysis (CPA) which includes both CPM and PERT, consists of following five steps:
1. Analyse and break down the project in terms of specific activities and/ or events. 2. Determine the interdependence and sequence of specific activities and prepare a net work.
3. Assign estimates of time, cost or both to all the activities of the network. 4. Identify the longest or critical path through the network. 5. Monitor, evaluate and control the progress of the project by replanning, rescheduling and reassignment of resources.
The central task in the control aspect of these models is to identify the longest path through the network. The longest path is the critical path because it equals the minimum time required to complete the project. All other paths other than the critical path (i.e. no critical or slack paths) offer flexibility in scheduling and transferring resources, because they take less time to complete than the critical path.
ADVANTAGES OF CRITICAL PATH ANALYSIS
There are a number of advantages in using critical path analysis. 1. It allows for a comprehensive view of the entire project. Because of the sequential and concurrent relationships, time scheduling becomes very...