Project Management: A Managerial Approach Chapter 8 – Scheduling © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Overview WBS to Schedule Process PERT Schedule Types CPM © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Scheduling A schedule is the conversion of a project action plan into an operating timetable It serves as the basis for monitoring and controlling project activity Taken together with the plan and budget, it is probably the major tool for the management of projects © 2006 John Wiley and Sons, Inc. Chapter 8-1

Simple Schedule – Gantt Chart © 2006 John Wiley and Sons, Inc.

Network Techniques: PERT and CPM With the exception of Gantt charts, the most common approach to scheduling is the use of network techniques such as PERT and CPM The Program Evaluation and Review Technique (PERT) was developed by the U.S. Navy in 1958 The Critical Path Method (CPM) was developed by DuPont, Inc during the same time period © 2006 John Wiley and Sons, Inc. Chapter 8-7

Scheduling Terminology Activity - A specific task or set of tasks that are required by the project, use up resources, and take time to complete Event - The result of completing one or more activities. An identifiable end state occurring at a particular time. Events use no resources. Network - The combination of all activities and events define the project and the activity precedence relationships © 2006 John Wiley and Sons, Inc. Chapter 8-9

Scheduling Terminology Path - The series of connected activities (or intermediate events) between any two events in a network Critical - Activities, events, or paths which, if delayed, will delay the completion of the project. A project’s critical path is understood to mean that sequence of critical activities that connect the project’s start event to its finish event © 2006 John Wiley and Sons, Inc. Chapter 8-10

Scheduling Terminology An activity can be in any of these conditions: It may have a successor(s) but no predecessor(s) - starts a network It may have a predecessor(s) but no successor(s) - ends a network It may have both predecessor(s) and successor(s) - in the middle of a network Interconnections from horizontal links in vertical WBS © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Hypothetical Network 2 5 6 1 4 3 16 20 13 30 TE=64 Calculate t(e) and Z for this network…… © 2006 John Wiley and Sons, Inc.

Activity and Project Frequency Distributions m b TE (A) (B) © 2006 John Wiley and Sons, Inc.

PERT Activity Calculation t(e) = a + 4m + b a = Most Optimistic (MO) 6 m = Most Likely (ML) b = Most Pessimistic (MP) t(e) = Activity Duration When a single estimate for activity time is not sufficient! © 2006 John Wiley and Sons, Inc.

PERT Schedule Probability Z = T(S) – T(E) Z = Probability of SSD(T[E])2 Meeting Schedule T(S) = Scheduled Duration T(E) = Critical Path Duration Z is derived from a table of predetermined probabilities © 2006 John Wiley and Sons, Inc.

PERT Activity Times & Variances b t(e) 1-2 17 29 47 2-3 6 12 24 2-4 16 19 28 3-5 13 4-5 2 5 14 5-6 8 © 2006 John Wiley and Sons, Inc.

Variance of Activity Estimates b t(e) [(b-a)/6]2 Var 1-2 17 29 47 30 2-3 6 12 24 13 2-4 16 19 28 20 3-5 4-5 2 5 14 5-6 8 © 2006 John Wiley and Sons, Inc.

Possible Project Durations TE=64 TS=67 © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Z Table Z Value Probability -2.0 0.02 +2.0 0.98 -1.5 0.07 +1.5 0.93 -1.0 0.16 +1.0 0.84 -0.7 0.24 +0.7 0.76 -0.5 0.31 +0.5 0.69 -0.3 0.38 +0.3 0.62 -0.1 0.36 +0.1 0.54 © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Gantt Charts The Gantt chart shows planned and actual progress for a number of tasks displayed against a horizontal time scale It is an effective and easy-to-read method of indicating the actual current status for each set of tasks compared to the planned progress for each item of the set It can be helpful in expediting, sequencing, and reallocating resources among tasks Gantt charts usually do not show technical dependencies © 2006 John Wiley and Sons, Inc. Chapter 8-14

© 2006 John Wiley and Sons, Inc. Drawing Networks Activity-on-Arrow (AOA) networks use arrows to represent activities while nodes stand for events Activity-on-Node (AON) networks use nodes to represent activities with arrows to show precedence relationships The choice between AOA and AON representation is largely a matter of personal preference © 2006 John Wiley and Sons, Inc. Chapter 8-12

© 2006 John Wiley and Sons, Inc. Hypothetical Network 3 1 2 5 6 4 © 2006 John Wiley and Sons, Inc.

AOA Network Building Blocks 80 79 Install software Event Activity © 2006 John Wiley and Sons, Inc.

Partial Koll Business Center - AOA 4 5 1 3 2 A Application approval D Service availability check C Traffic study B Construction plans © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Partial AOA Network 2 3 1 4 A X C B E (A) (B) (C) © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Partial AOA Network 2 3 1 4 A B C X E (D) 5 D 2 3 1 4 A B C X E (E) 5 D F ? © 2006 John Wiley and Sons, Inc.

KOLL BUSINESS CENTER County Engineers Design Department Full AOA Network 2 3 1 4 A 5 B C 10 X 5 15 6 7 8 Y F 10 G 170 H 35 E 15 D 5 Legend KOLL BUSINESS CENTER County Engineers Design Department Activity Duration © 2006 John Wiley and Sons, Inc.

Activity-on-Node Network Fundamentals X Y Z Y and Z are preceded by X Y and Z can begin at the same time, if you wish (B) A B C A is preceded by nothing B is preceded by A C is preceded by B (A) J K L M J, K, & L can all begin at the same time, if you wish (they need not occur simultaneously) All (J, K, L) must be completed before M can begin but AA (C) (D) Z is preceded by X and Y AA is preceded by X and Y © 2006 John Wiley and Sons, Inc.

© 2006 John Wiley and Sons, Inc. Copyright 2006 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein. © 2006 John Wiley and Sons, Inc.