# PERT Estimation Technique

Any project with interdependent activities can apply this method of mathematical analysis. The first time CPM was used for major skyscraper development was in 1966 while constructing the former World Trade Center Twin Towers in New York City. Although the original CPM program and approach is no longer used, the term is generally applied to any approach used to analyze a project network logic diagram. PERT became part of Project Management literature after statistical and research findings.

Due to the budget constraints it might be difficult to effectively apply the most appropriate methodological instruments. A PERT chart, sometimes called a PERT diagram, is a project management tool used to schedule, organize and coordinate tasks within a project.

It is commonly used in conjunction with the program evaluation and review technique (PERT). A critical path is determined by identifying the longest stretch of dependent activities and measuring the time required to complete them from start to finish. Potter identifies and describes three broad paradigms within program evaluation .

## Events and activities

See how PERT charts compare to Gantt charts for project management. PERT (Program Evaluation Review Technique) is an estimation technique which was first developed and applied by United States Defence establishment for their Ballistic Missile development program. Completion of this in time, ahead of the other nations was critical for them. Such missile development program was filled with huge amount of uncertainty, as it required large number supplier agencies working on new technology development.

Nevertheless, the truth is that CPM is different from PERT in a way that the latter concentrates on time while the former stresses on the time-cost trade-off. In the same manner, there are many differences between PERT and CPM, which we are going to discuss in this article.

## As project scheduling tool

This method of estimation which helped them build-in all the uncertainties in their estimates and helped them to complete this program ahead of their expected schedule. Originally, the critical path method considered only logical dependencies between terminal elements. Since then, it has been expanded to allow for the inclusion of resources related to each activity, through processes called activity-based resource assignments and resource optimization techniques such as Resource Leveling and Resource smoothing. A related concept is called the critical chain, which attempts to protect activity and project durations from unforeseen delays due to resource constraints.

They also offer the benefit of being easy to change, which is helpful. Charts may be adjusted frequently to reflect the actual status of project tasks as, almost inevitably, they diverge from the original plan. Project network diagrams are often called PERT charts because they are used with the Program Evaluation and Review Technique.

### What is a Program Evaluation Review Technique PERT chart?

A PERT chart, sometimes called a PERT diagram, is a project management tool used to schedule, organize and coordinate tasks within a project. PERT stands for Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program.

The Program Evaluation Review Technique, or PERT, is a visual tool used in project planning. Using the technique helps project planners identify start and end dates, as well as interim required tasks and timelines.

The critical path through these tasks takes at least eight days. PERT and CPM are techniques of project management useful in the basic managerial functions of planning, scheduling and control. PERT stands for “Programme Evaluation & Review Technique” and CPM are the abbreviation for “Critical Path Method”.

To determine the critical path, add the amount of time estimated for the duration of each activity to the previous activity, as shown in Figure 8.10. Durations are indicated in days and activities on the critical path are shaded.

The Program Evaluation Review Technique (PERT) breaks down the individual tasks of a project for analysis. PERT charts are considered preferable to Gantt charts because they identify task dependencies, but they’re often more difficult to interpret. The critical path method (CPM), or critical path analysis (CPA), is an algorithm for scheduling a set of project activities.

• It is basically a method to analyze the tasks involved in completing a given project, especially the time needed to complete each task, and to identify the minimum time needed to complete the total project.
• A PERT chart is a project management tool used to schedule, organize, and coordinate tasks within a project.
• PERT Chart is acronym for (Program Evaluation and Review Technique).

This path, with the constraint-generated total float would actually make the path longer, with total float being part of the shortest possible duration for the overall project. In other words, individual tasks on the critical path prior to the constraint might be able to be delayed without elongating the critical path; this is the ‘total float’ of that task. However, the time added to the project duration by the constraint is actually critical path drag, the amount by which the project’s duration is extended by each critical path activity and constraint. A PERT chart is a project management tool that provides a graphical representation of a project’s timeline.

These days the projects undertaken by business houses are very large and take a number of years before commercial production can start. Critical Path Analysis is commonly used with all forms of projects, including construction, aerospace and defense, software development, research projects, product development, engineering, and plant maintenance, among others.

Developed in the late 1950s, Critical Path Method or CPM is an algorithm used for planning, scheduling, coordination and control of activities in a project. Here, it is assumed that the activity duration is fixed and certain. CPM is used to compute the earliest and latest possible start time for each activity. The two scheduling methods use a common approach for designing the network and for ascertaining its critical path. They are used in the successful completion of a project and hence used in conjunction with each other.

The first, and probably most common, is the positivist approach, in which evaluation can only occur where there are “objective”, observable and measurable aspects of a program, requiring predominantly quantitative evidence. PERT stands for Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program. A similar methodology, the Critical Path Method (CPM) was developed for project management in the private sector at about the same time. Image by Be the Change, Inc.If any activity on the critical path is delayed, the completion of the project will be delayed by an equal amount.

PERT Chart is acronym for (Program Evaluation and Review Technique). A PERT chart is a project management tool used to schedule, organize, and coordinate tasks within a project. It is basically a method to analyze the tasks involved in completing a given project, especially the time needed to complete each task, and to identify the minimum time needed to complete the total project. Program Evaluation and Review Technique (PERT) is a method used to examine the tasked that are in a schedule and determine a variation of the Critical Path Method (CPM). It analyzes the time required to complete each task and its associated dependencies to determine the minimum time to complete a project.

This determines the shortest time possible to complete the project. There can be ‘total float’ (unused time) within the critical path. For example, if a project is testing a solar panel and task ‘B’ requires ‘sunrise’, there could be a scheduling constraint on the testing activity so that it would not start until the scheduled time for sunrise. This might insert dead time (total float) into the schedule on the activities on that path prior to the sunrise due to needing to wait for this event.

It estimates the shortest possible time each activity will take, the most likely length of time, and the longest time that might be taken if the activity takes longer than expected. The method was developed by the US Navy in 1957 on the Polaris nuclear submarine project.

## Uncertainty in project scheduling

PERT was initially developed by US Navy to take care of scheduling uncertainties. The formula mentioned above is a close approximation of Mean found by Beta Distribution. PERT is frequently used along with CPM (Critical Path Method) for Project Scheduling. Therefore, this automatically results in evaluations being allocated smaller budgets that are inadequate for a rigorous evaluation.

It provides a graphical representation of a project’s timeline that allows project managers to break down each individual task in the project for analysis. Gantt charts give a clear illustration of project status, but one problem with them is that they don’t indicate task dependencies – you cannot tell how one task falling behind schedule affects other tasks. The PERT chart, another popular project management charting method, is designed to do this. Automated Gantt charts store more information about tasks, such as the individuals assigned to specific tasks, and notes about the procedures.

Critical path analysis is a project planning method that involves creating a chart of key tasks that must be completed to deliver a project on schedule. Programs that do not do a needs assessment can have the illusion that they have eradicated the problem/need when in fact there was no need in the first place. Needs assessment involves research and regular consultation with community stakeholders and with the people that will benefit from the project before the program can be developed and implemented. In this way potential problems can be realized early because the process would have involved the community in identifying the need and thereby allowed the opportunity to identify potential barriers.

Here is the video tutorial about PERT (Program Evaluation and Review Techniques) under Project management in Operations Research. for this information we have work out the problem in simple manner, hope this will help you to get the subject knowledge at the end. if you like this please like, comment, share and subscribe. Using these values, CPM calculates the longest path of planned activities to logical end points or to the end of the project, and the earliest and latest that each activity can start and finish without making the project longer. In project management, a critical path is the sequence of project network activities which add up to the longest overall duration, regardless if that longest duration has float or not.