Project Management: A Managerial Approach Chapter – Scheduling © 2006 John Wiley Overview • • • • WBS to Schedule Process PERT Schedule Types CPM © 2006 John Wiley 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 Chapter 8-1 Simple Schedule – Gantt Chart © 2006 John Wiley 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 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 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 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 Hypothetical Network 13 30 16 20 Calculate t(e) and Z for this network…… © 2006 John Wiley TE=64 Activity and Project Frequency Distributions ACTIVITY a PROJECT m b (A) © 2006 John Wiley TE (B) PERT Schedule Probability Z = T(S) – T(E) SD(T[E])2 Z = Probability of Meeting Schedule T(S) = Scheduled Duration T(E) = Critical Path Duration Z is derived from a table of predetermined probabilities © 2006 John Wiley PERT Activity Times & Variances Activity a m b 1-2 17 29 47 2-3 12 24 2-4 16 19 28 3-5 13 16 19 4-5 14 5-6 © 2006 John Wiley t(e) Variance of Activity Estimates Activity a m b t(e) 1-2 17 29 47 30 2-3 12 24 13 2-4 16 19 28 20 3-5 13 16 19 16 4-5 14 5-6 © 2006 John Wiley [(b-a)/6]2 Var Possible Project Durations TS=67 TE=64 © 2006 John Wiley Z Table Z Value Probability 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 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 not show technical dependencies © 2006 John Wiley Chapter 8-14 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 Chapter 8-12 Hypothetical Network © 2006 John Wiley AOA Network Building Blocks Activity 79 Install software © 2006 John Wiley Event 80 Partial Koll Business Center - AOA A Application approval B Construction plans C Traffic study D Service availability check © 2006 John Wiley Partial AOA Network X A C 2 (B) C X E X C B A (A) B A B (C) © 2006 John Wiley E E Partial AOA Network B A X C E D (D) B A C X D (E) © 2006 John Wiley E ? F Full AOA Network B 15 X A Legend Activity Duration C 10 0 Y E 15 F 10 D © 2006 John Wiley G 170 H 35 KOLL BUSINESS CENTER County Engineers Design Department Activity-on-Node Network Fundamentals J, K, & L can all begin at the same time, if you wish (they need not occur simultaneously) J A B C K A is preceded by nothing B is preceded by A C is preceded by B L (A) M (C) but All (J, K, L) must be completed before M can begin Y Y and Z are preceded by X X Z Z is preceded by X and Y Z Y and Z can begin at the same time, if you wish Y AA AA is preceded by X and Y X (B) (D) © 2006 John Wiley 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 ... 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... approval B Construction plans C Traffic study D Service availability check © 2006 John Wiley Partial AOA Network X A C 2 (B) C X E X C B A (A) B A B (C) © 2006 John Wiley E E Partial AOA Network... Wiley Chapter 8-12 Hypothetical Network © 2006 John Wiley AOA Network Building Blocks Activity 79 Install software © 2006 John Wiley Event 80 Partial Koll Business Center - AOA A Application approval