Page 121 - DMGT302_FUNDAMENTALS_OF_PROJECT_MANAGEMENT

Fundamentals of Project Management Dilfraz Singh, Lovely Professional University

Notes Unit 7: Project Scheduling

CONTENTS
Objectives
Introduction
7.1 Brief History of CPM/PERT

7.2 Language of PERT/CPM
7.3 Project Uncertainty and Risk Management
7.4 Planning, Scheduling & Control
7.5 Tabulation & Analysis of Activities
7.6 PERT (Probabilistic) Approach
7.7 Summary

7.8 Keywords
7.9 Review Questions
7.10 Further Readings

Objectives

After studying this unit, you will be able to:

Know about project scheduling;
Understand the language of PERT;
Know about extensions to PERT/CPM.

Introduction

In the late 1950s, the Program Evaluation and Review Technique (PERT) and the Critical Path
Method (CPM) were independently developed. PERT was developed by the U.S. Navy,
Booz-Allen Hamilton (a business consulting firm), and Lockheed Aircraft (now Lockheed Martin
Corp.); and CPM was developed by Dupont De Nemours Inc. When they were developed, there
were significant differences in the methods.

Example: PERT used probabilistic (or uncertain) estimates of activity durations and
CPM used deterministic (or certain) estimates but included both time and cost estimates to
allow time/cost trade-offs to be used. Both methods employed networks to schedule and display
task sequences. (Throughout this unit, we will use the words “activity” and “task” as synonyms
to avoid constant repetition of one or the other.)
Both methods identified a critical path of tasks that could not be delayed without delaying the
project. Both methods identified activities with slack (or float) that could be somewhat delayed
without extending the time required to complete the project. While PERT and CPM used slightly
different ways of drawing the network of activities, anything one could do with PERT, one could
also do with CPM and vice versa. When writing about the history of project management,
differentiating PERT and CPM is important and interesting. When managing projects, the

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