Effective Project Management: Exploring the Network Techniques of CPM and PERT

The network technique is a major advance in management science. This technique is based on the basic characteristics of all projects, that all work must be done in well-defined steps. For example, for completing a foundation, the various steps are (1) Layout, (ii) Digging, (iii) Placing Sideboards, and (iv) Concreting.

The network technique exploits this characteristic by representing the steps of the project objective graphically in the form of a network or arrow diagram. It would be difficult to find in the history of management methods any technique which has received such widespread attention as that accorded to network methods for planning, scheduling, and controlling.

The network techniques are called by various names such as PERT, CPM, UNETICS, LESS, TOPS, and SCANS. However, these and other systems have emerged from the following two major network system:

1. CPM
2. PERT

What Is CPM?

Critical Path Method

CPM Full name Critical Path Method.

Critical Path Method (CPM) is an effective tool for scheduling the activities of a complex Project. It was developed by Morgan R. Walker of DuPont and James E. Kelley Jr. of Remington in 1950.

In CPM networks, the entire project consists of a number of clearly recognizable operations or jobs, called activities. Activities are usually operations that take time to carry out, and on which resources are an expense.

Junctions between activities are term as events. The CPM net-works are often referred to as activity-oriented diagrams in which an arrow represents each activity, and the sequence of the arrows shows the sequence in which the activities are performed.

For example, at a foundation construction project, the various activities may be; layout the foundation trench’, ‘excavate the foundation,’ ‘put sideboards,’ ‘concrete the foundation base,’ etc.

CPM network is generally used for repetitive kind projects, or for those projects for which a quite accurate estimate of time for completion of each activity may be made; and for which cost estimations may be made using a fair degree of accuracy. For example, CPM is very helpful for construction projects. But it isn’t suitable for development and research projects.

CPM Basic Steps:

1. Determine the required tasks
2. List required tasks in sequence
3. Create a flowchart including each required task
4. Identify all critical and non-critical relationships (paths) among the required tasks
5. Assign an expected completion/execution time for each required task
6. Study all critical relationships to determine all possible alternatives or backups for as many as possible

What Is PERT?

Program Evaluation Review Technique 

PERT full name Program Evaluation Review Technique. 

This PERT method First developed by the United States Navy in 1958, is commonly used in conjunction with the critical path method in the year 1957 (CPM).

The method was developed from the Navy Special Projects Office at co-operation with Booz, Allen, and Hamilton, a management consulting firm, also Lockheed Missile System Division for assessing the feasibility of existing schedules on Polaris missile program and for reporting progress.

The PERT system uses a network diagram consisting of pf events that have to be established to reach project objectives. An event is that particular instant of time where some specific part of a plan is to be achieved. It indicates a point in time and does not require any resources. PERT uses event-oriented network diagrams in which arrows join successive events.

For example, at a foundation construction project, the various events could be’foundation layout started,” foundation excavated,” sideboards fixed,” concreting completed’ etc. The approach of event-orientation in the network diagram grew out of the desire to report on the project progress via discernible management milestones.

PERT Basic Steps:

1. Identifying Tasks and Milestones: Each project involves a series of required tasks. These tasks are listed in a table, permitting additional information on timing and sequence to be added later.
2. Placing the Tasks at a Proper Sequence: The tasks Have Been Examined and placed in a sequence to get the desired results.
3. Network Diagramming: A network diagram is drawn with the activity sequence data showing the sequence of concurrent and sequential activities.
4. Time Estimating: Here Can Be the time required to carry out each activity, in three parts:
   1. Optimistic timing: The shortest time to complete an activity
   2. Most likely timing: The completion time having the highest probability
   3. Pessimistic timing: The longest time to complete an activity
5. Critical Path Estimating: This determines the entire time required to complete a project.

CPM Vs. PERT

FAQ: CPM and PERT in Project Management

What Are Network Techniques in Project Management?

Network techniques are methods used to represent the steps of a project graphically in the form of a network or arrow diagram. They are essential for planning, scheduling, and controlling project activities.

What Is the Critical Path Method (Cpm)?

CPM, or Critical Path Method, is a tool for scheduling project activities. Developed by Morgan R. Walker and James E. Kelley Jr. in 1950, CPM identifies the sequence of critical and non-critical tasks to complete a project efficiently.

What Are the Basic Steps in Cpm?

1. Determine the required tasks.
2. List tasks in sequence.
3. Create a flowchart including each task.
4. Identify critical and non-critical relationships among tasks.
5. Assign expected completion times for each task.
6. Analyze critical relationships to determine alternatives or backups.

What Is the Program Evaluation Review Technique (Pert)?

PERT, or Program Evaluation Review Technique, was developed by the U.S. Navy in 1958. It is used to manage uncertain activities in projects by employing a network diagram consisting of events that need to be achieved.

What Are the Basic Steps in Pert?

1. Identify tasks and milestones.
2. Sequence tasks to achieve desired results.
3. Create a network diagram with activity sequence data.
4. Estimate the time required for each activity (optimistic, most likely, and pessimistic timing).
5. Determine the critical path to estimate the total project duration.

What Are the Key Differences Between Cpm and Pert?

1. Orientation: CPM is activity-oriented, while PERT is event-oriented.
2. Focus: CPM focuses on cost and time, whereas PERT focuses primarily on time.
3. Model Type: CPM uses a deterministic model; PERT uses a probabilistic model.
4. Time Estimates: CPM involves a single time estimate per activity; PERT includes three time estimates (optimistic, most likely, and pessimistic).
5. Application: CPM is suitable for repetitive projects with well-defined activities; PERT is used for projects with uncertain, non-repetitive activities.

Can Cpm Be Used for Research and Development Projects?

No, CPM is not suitable for research and development projects due to the uncertainty and variability of tasks in such projects. PERT is more appropriate for these types of projects.

How Do Cpm and Pert Handle Critical and Non-Critical Activities?

1. CPM: Differentiates between critical and non-critical activities to optimize time and cost management.
2. PERT: Does not differentiate between critical and non-critical activities but focuses on the sequence of events to reach project milestones.

What Industries Commonly Use Cpm and Pert?

1. CPM: Commonly used in construction, shipbuilding, and other industries where project activities are repetitive and well-defined.
2. PERT: Frequently used in research and development projects, especially where activities are uncertain and non-repetitive.

Why Are Network Techniques Like Cpm and Pert Significant in Project Management?

Network techniques like CPM and PERT provide a structured approach to planning, scheduling, and controlling project activities. They help project managers identify critical tasks, optimize resource allocation, and ensure timely project completion.