Program_Evaluation_and_Review_Technique.pptx

Program_Evaluation_and_Review_Technique.pptx

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  Program Evaluation andReview Technique (PERT) Ms Mamta Bisht Assistant Professor
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  2 Program (Project) Evaluationand Review Technique(PERT) PERT 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.
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  ■ OBJECTIVE: The mainobjective of PERT is to facilitate decision making and to reduce both the time and cost required to complete a project. ■ FIELD OF APPLICATION: PERT is intended for very large scale, one time, non routine, complex projects with a high degree of inter task dependency, projects which require a series of activities, some of which must be performed sequentially and others that can be performed in parallel with other activities. 3
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  PERT planning involvesthe following steps that are described below. 1. Identify the specific activities and milestones. The activities are the tasks required to complete a project. 2. Determine the proper sequence of the activities. Proper sequential of activities. 4
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  3. Construct anetwork diagram. Using the activity sequence information, a network diagram can be drawn showing the sequence of the serial and parallel activities. Each activity represents a node in the network, and the arrows represent the relation between activities. Software packages simplify this step by automatically converting tabular activity information into a network diagram. 5
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  4. Estimate thetime required for each activity. Weeks are a commonly used unit of time for activity completion, but any consistent unit of time can be used . A distinguishing feature of PERT is its ability to deal with uncertainty in activity completion time. For each activity, the model usually includes three time estimates: 6
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  Optimistic time –generallythe shortest time in which the activity can be completed. Most likely time –the completion time having the highest probability. Pessimistic time –the longest time that an activity might require. 7
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  Expected time = (Optimistic + 4 x Most likely + Pessimistic ) / 6 8
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  5. Determine thecritical path. The critical path is determined by adding the times for the activities in each sequence and determining the longest path in the project. The critical path determines the total calendar time required for the project. If activities outside the critical path speed up to slow down (within limits), the total project time does not change. The amount of time that a non –critical path activity can be delayed without the project is referred to as a slack time. 9
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  If the criticalpath is not immediately obvious, it may be helpful to determine the following four quantities for each activity: ES–Earliest Start time EF-Earliest Finish time LS –Latest Start time LF -Latest Finish time 10
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  6. Update thePERT chart as the project progresses. Make adjustments in the PERT chart as the project progresses. As the project unfolds, the estimated times can be replaced with actual times. In cases where there are delays, additional resources may be needed to stay on schedule and the PERT chart may be modified to reflect the new situation. 11
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  EXAMPLES In the followingexample, the Project manager knows the succession of the project activities and the optimistic, Pessimistic and most likely time (in weeks) for the following activities: 12
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  The earliest starttime, earliest finish time, latest start time and latest finish time for each activity are calculated in the following table: 16
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  Chapter 8 Scheduling,PERT, Critical Path Analysis 17
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  Chapter 8 Scheduling,PERT, Critical Path Analysis 19