Project Management -- Developing the Project Plan

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1 Project Management -- Developing the Project Plan Dr. Tai-Yue Wang Department of Industrial and Information Management National Cheng Kung University Tainan, TAIWAN, ROC 1

2 Where We Are Now 6 2

3 Developing the Project Plan The Project Network A flow chart that graphically depicts the sequence, interdependencies, and start and finish times of the project job plan of activities that is the critical path through the network. 6 3

4 Developing the Project Plan Provides the basis for scheduling labor and equipment. Enhances communication among project participants. Provides an estimate of the project s duration. Provides a basis for budgeting cash flow. Identifies activities that are critical. Highlights activities that are critical and can not be delayed. Help managers get and stay on plan. 6 4

5 WBS/Work Packages to Network FIGURE

6 WBS/Work Package to Network (cont d) FIGURE 6.1 (cont d) 6 6

7 Constructing a Project Network Terminology Activity: an element of the project that requires time. Merge Activity: an activity that has two or more preceding activities on which it depends. Parallel (Concurrent) Activities: Activities that can occur independently and, if desired, not at the same time. A B D C 6 7

8 Constructing a Project Network (cont d) Terminology Path: a sequence of connected, dependent activities. Critical path: the longest path through the activity network that allows for the completion of all project-related activities; the shortest expected time in which the entire project can be completed. Delays on the critical path will delay completion of the entire project. 6 8

9 Constructing a Project Network (cont d) C A B D (Assumes that minimum of A + B > minimum of C in length of times to complete activities.) 6 9

10 Constructing a Project Network (cont d) Terminology Event: a point in time when an activity is started or completed. It does not consume time. Burst Activity: an activity that has more than one activity immediately following it (more than one dependency arrow flowing from it). A B C D 6 10

11 Constructing a Project Network (cont d) Two Approaches Activity-on-Node (AON) Uses a node to depict an activity. Activity-on-Arrow (AOA) Uses an arrow to depict an activity. A B C D 6 11

12 Basic Rules to Follow in Developing Project Networks 1. Networks typically flow from left to right. 2. An activity cannot begin until all preceding connected activities are complete. 3. Arrows indicate precedence and flow and can cross over each other. 4. Each activity must have a unique identify number that is greater than any of its predecessor activities. 6 12

13 Basic Rules to Follow in Developing Project Networks 5. Looping is not allowed. 6. Conditional statements are not allowed. 7. Use common start and stop nodes. 6 13

14 Activity-on-Node Fundamentals 6 14

15 Activity-on-Node Fundamentals (cont d) FIGURE 6.2 (cont d) 6 15

16 Network Information TABLE

17 Automate Warehouse Partial Network FIGURE

18 Automated Warehouse Complete Network FIGURE

19 Network Computation Process Forward Pass Earliest Times How soon can the activity start? (early start ES) How soon can the activity finish? (early finish EF) How soon can the project finish? (expected time ET) 6 19

20 Network Computation Process Backward Pass Latest Times How late can the activity start? (late start LS) How late can the activity finish? (late finish LF) Which activities represent the critical path? How long can activity be delayed? (slack or float SL) 6 20

21 Network Information TABLE

22 Activity-on-Node Network FIGURE

23 Activity-on-Node Network Forward Pass FIGURE

24 Forward Pass Computation Add activity times along each path in the network (ES + Duration = EF). Carry the early finish (EF) to the next activity where it becomes its early start (ES) unless The next succeeding activity is a merge activity, in which case the largest EF of all preceding activities is selected. 6 24

25 Activity-on-Node Network Backward Pass FIGURE

26 Backward Pass Computation Subtract activity times along each path in the network (LF - Duration = LS). Carry the late start (LS) to the next activity where it becomes its late finish (LF) unless The next succeeding activity is a burst activity, in which case the smallest LF of all preceding activities is selected. 6 26

27 Determining Free Slack (or Float) Free Slack (or Float) Is the amount of time an activity can be delayed after the start of a longer parallel activity or activities. Is how long an activity can exceed its early finish date without affecting early start dates of any successor(s). Allows flexibility in scheduling scarce resources. 6 27

28 Determining Free Slack (or Float) Sensitivity The likelihood the original critical path(s) will change once the project is initiated. The critical path is the network path(s) that has (have) the least slack in common. 6 28

29 Forward and Backward Passes Completed with Slack Times FIGURE

30 Practical Considerations Network Logic Errors Activity Numbering Use of Computers to Develop Networks Calendar Dates Multiple Starts and Multiple Projects 6 30

31 Network Logic Errors: Illogical Loop FIGURE

32 Automated Warehouse Order Picking System Network FIGURE

33 Automated Order Warehouse Picking System Bar Chart FIGURE

34 Extended Network Techniques to Come Close to Reality Laddering Activities are broken into segments so the following activity can begin sooner and not delay the work. 6 34

35 Lags Extended Network Techniques to Come Close to Reality The minimum amount of time a dependent activity must be delayed to begin or end. Lengthy activities are broken down to reduce the delay in the start of successor activities. Lags can be used to constrain finish-to-start, start-tostart, finish-to-finish, start-to-finish, or combination relationships. 6 35

36 Example of Laddering Using Finish-to-Start Relationship FIGURE

37 FIGURE 6.14 Use of Lags Finish-to-Start Relationship Start-to-Start Relationship FIGURE 6.13

38 Use of Lags Cont d Use of Lags to Reduce Project Duration FIGURE

39 New Product Development Process FIGURE

40 Use of Lags (cont d) Finish-to-Finish Relationship FIGURE 6.17 Start-to-Finish Relationship FIGURE 6.18 Combination Relationship FIGURE 6.19

41 Network Using Lags FIGURE

42 Hammock Activities ( 吊床活動 ) Hammock Activity Spans over a segment of a project. Has a duration that is determined after the network plan is drawn. Is used to aggregate sections of the project to facilitate getting the right amount of detail for specific sections of a project. Is very useful in assigning and controlling indirect project costs. 6 42

43 Hammock Activity Example FIGURE

44 Common Elements of Project Plan 1. Scope Statement, Charter, or SOW 2. Detailed requirements 3. Detailed work definition (WBS and work package details) 4. Responsibility for work tasks 5. Detailed schedules and milestones 1. Gantt charts 2. Networks 6. Project budget and cost accounts 44

45 Gantt Chart 45

46 Tasks Gantt Chart A B C D E F G H What is affect of Time C starting 2 weeks late? C starting 6 weeks late? E taking 3 weeks instead of 2 weeks? E finishing a week early? 46

47 Network Diagrams: Scheduling Using Network Methods AON method: Activity on Node Each activity (work package or task) in project is represented by a node (a circle or box) Activity A A or A A project is represented by a network of nodes connected with arrows arranged in sequence as specified by immediate predecessors 47

48 Network Diagrams: AON Example Activity Immediate Time A B Gantt Chart Predecessors A -- 1 B A 2 C B 3 D C E D B 1 E C, D 2 F F E Time

49 Network Diagrams: AON (cont d) Example Activity Immediate Predecessors A -- B A C B D B E C, D F E A B 49

50 Network Diagrams: AON (cont d) Example Activity Immediate Predecessors A -- B A C B D B E C, D F E A B C D 50

51 AON (cont d) Example Activity Immediate Predecessors C A -- A B E F B C A B D D B E C, D F E 51

52 Network Diagrams: AON (cont d) When a network has dangling nodes at the start or end of the project, cannot tell where project starts or ends. A C B H I D F G J K E L 52

53 Network Diagrams: AON (cont d) The network should have one start node and one end node B A I start C H D G K end J F E L 53

54 Network Diagrams: Activities in the network should be based upon work packages from the WBS 54

55 Network Diagrams: Computer generated network diagrams 55

56 Network Diagrams: Scheduling Using a Network How do we schedule activities on the network? C, 3 A, 1 B, 2 E, 2 F, 3 D, 1 56

57 The Critical Path: Creating the Schedule Assume project starts at time 0. Start at first node, work left-to-right, adding duration times. Project start start = 3 finish = 6 C, 3 A, 1 B, 2 E, 2 F, 3 start = 0 finish = 1 start = 1 finish = 3 D, 1 start =? start = 3 finish = 4 57

58 The Critical Path: Creating the Schedule If an activity has multiple immediate predecessors (activity E), must wait until all are finished before starting. start = 3 finish = 6 C, 3 A, 1 B, 2 E, 2 F, 3 start = 0 finish = 1 start = 1 finish = 3 D, 1 start = 3 finish = 4 start = 6 finish = 8 start = 8 finish = 11 58

59 The Critical Path: Creating the Schedule Note: Here, ignore fact that in reality an activity will finish on one day or week and the next activity will start on following day or week. To simplify, assume that when an activity is finished, its successors start immediately. 59

60 Tasks The Critical Path: Creating the Schedule start = 3 finish = 6 C, 3 A, 1 B, 2 E, 2 F, 3 start = 0 finish = 1 A start = 1 finish = 3 B C D, 1 start = 3 finish = 4 start = 6 finish = 8 start = 8 finish = 11 Note: Results are same if had created a Gantt chart. D E F

61 The Critical Path: Creating the Schedule -- Early Times These times are called Early Times the earliest activities can be started and finished Early times give only half the time information needed to create a realistic, feasible schedule Early times do not consider potential constraints 61

62 The Critical Path: Creating the Schedule -- Early Times (cont d) Suppose 1. Contractor for D cannot start in week (has prior commitment); must wait until week 5 2. E cannot be completed in 2 weeks (shortage of personnel); will require 3 weeks to complete What affect will these have on project? start = 3 finish = 6 C, 3 A, 1 B, 2 E, 2 F, 3 start = 0 finish = 1 start = 1 finish = 3 D, 1 start = 3 finish = 4 start = 6 finish = 8 start = 8 finish = 11 62

63 Tasks The Critical Path: Creating the Schedule -- Early Times (cont d) A B D C E F Answers No affect. However, if D s start were delayed until week 6, it would delay project completion date. 2. If E exceeds 2 week duration by any amount, project will be delayed 12 63

64 The Critical Path: Creating the Schedule -- Early Times (cont d) To quickly answer questions like these, need to know more than Early Times Need also to know Late Times 64

65 The Critical Path: Late Times Late times: latest times activities must be started or finished in order to complete project by target date To compute late times, start at last node in project, specify target completion, and work backwards finish = 6 start = 3 Start here: Target Completion = 11 finish =? C, 3 finish = 8 start = 6 finish = 11 start = 8 A, 1 B, 2 E, 2 F, 3 D, 1 finish = 6 start = 5 65

66 The Critical Path: Late Times (cont d) Notice, the late finish for an activity is based on late start for its successor. If an activity has more than one successor, late finish is based on earliest of its successors. Hence, late finish for B is 3, which is late start for earliest of its successors, C. Were B to finish any later than 3, C would be delayed, as would E and F finish = 1 start = 0 finish = 3 start = 1 finish = 6 start = 3 C, 3 finish = 8 start = 6 finish = 11 start = 8 A, 1 B, 2 E, 2 F, 3 D, 1 finish = 6 start = 5 66

67 The Critical Path: Early and Late Times To simplify presentations from here on use Where ES EF LS LF ES = early start EF = early finish LS = late start LF = late finish 67

68 The Critical Path: Early and Late Times (cont d) ACTIVITY, TIME ES LS EF LF C, A, 1 B, 2 E, 2 F, 3 D,

69 The Critical Path: Early and Late Times (cont d) Another example ES EF LS LF C, 2 A, 1 E, 2 G, 6 Start B, 3 D, 7 F, 3 H, 1 End 69

70 The Critical Path: Early and Late Times (cont d) 1 3 ES EF LS LF 0 1 C, 2? A, E, 2 G, 6 Start D, 7 End B, F, 3? H, 1 70

71 The Critical Path: Early and Late Times (cont d) 1 3 ES EF LS LF 0 1 C, A, E, 2 G, 6 Start D, 7 End B, F, 3 H,

72 The Critical Path: Early and Late Times (cont d) Suppose target date is 16 weeks C, A, 1 D, 7 Start B, E, 2 ES EF LS LF G, 6 F, 3 H, End 72

73 The Critical Path: Early and Late Times (cont d) Start 0 1 A, 1 1 3? C, 2 1 8? D, 7 B, 3 0 3? E, G, 6 F, 3 H, ES EF LS LF End 73

74 The Critical Path: Early and Late Times (cont d) Start 0 1? A, C, D, 7 B, E, G, 6 F, 3 H, ES EF LS LF End 74

75 The Critical Path: Early and Late Start Times (cont d) C, A, D, 7 B, E, G, 6 F, 3 H, ES EF LS LF End In project management software this information is displayed in tabular form 75

76 The Critical Path: Early and Late Times (cont d) Start Finish Late Start Late Finish 76

77 The Critical Path: Project Duration -- How Long Will the Project Take? Quick way to determine duration of project: Identify longest path through network from the start node to the end node 77

78 The Critical Path: Project Duration (cont d) A, C, ES EF LS LF E, 2 (Can ignore these!) G, 6 Start D, 7 End B, F, 3 H,

79 The Critical Path: Project Duration (cont d) C, 2 A, 1 E, 2 G, 6 Start D, 7 End B, 3 F, 3 H, 1 Longest path is A-D-E-G, 16 weeks, thus, project duration is 16 weeks 79

80 The Critical Path: Slack Times Difference between early and late times represent slack (or float ) of an activity LS ES = slack or LF EF = slack 80

81 The Critical Path: Slack Times Start m = slack time How much activity can exceed expected duration C, A, E, 2 G, 6 D, 7 End B, Slack represents scheduling flexibility How much an activity can be delayed F, 3 H,

82 The Critical Path: Slack Times Start Activities F and H both have slack of 4 weeks. However, both are on same sub-path, hence, 4 weeks represents combined slack for both activities. (If F is delayed 1 week, H has 3 weeks of slack remaining) C, A, E, 2 D, B, G, 6 F, 3 H, End 82

83 The Critical Path: Early and Late Times (cont d) Start Finish Late Start Late Finish Slack 83

84 The Critical Path: Critical Path Notice the path with 0 total slack This path is also the Critical Path Start C, A, E, 2 D, B, Critical Path CP = A-D-E-G G, 6 F, 3 H, End 84

85 The Critical Path: Critical Path (cont d) CP has least slack Also, CP is the Longest Path C, 2 Start A, 1 B, 3 D, 7 E, 2 F, 3 G, 6 H, 1 End Activities on CP are called critical activities Activities not on CP are called non critical activities Any delay on any activity on CP will delay project. 85

86 The Critical Path: Critical Path (cont d) CP has least slack in project (though not always 0. If, e.g., target of project is 18 weeks, slack on CP will be 2, but 2 more everywhere else). Start A, C, D, 7 B, E, 2 F, CP = A-D-E-G G, H, Target Date = 18End 86

87 The Critical Path: Free Slack Free slack is the time an activity can be delayed without delaying the start of any successor activity. Free slack for a activity = ES - EF 87

88 Management Schedule Reserve: PDM Networks AON presumes a finish-to-start relationship (immediate predecessors must finish before successors can start) PDM (Precedence Diagramming Method) shows kinds of relationships in projects Start activity when predecessors are only partially completed Start activity n days after start of predecessor Start activity n days after predecessors are completed Finish activity n days after finished predecessor With Lags. 88

89 Network Diagrams: PDM Networks Examples A FS = 1 Start B 1 day after finish A B A FF = 5 B Finish B 5 days after finish A A SS = 3 B Start B 3 days after start A With most project management software, you can schedule using PDM method 89

90 Sample problem Specify ES, EF, LS, LF, critical path, and slack times ES EF LS LF D, 3 F, 5 C, 1 L, 2 J, 3 Q, 6 M, 3 Assume LF = EF R, 2 90

91 Early times ? 0 2 L, 2 D, 3 F, Q, 6 J, R, C, 1 M, 3 91

92 Early times D, 3 F, 5 C, 1? 5 11 L, 2 M, 3 Q, 6 J, R,

93 Early times D, 3 F, 5 C, ? L, 2 M, 3 Q, 6 J, R,

94 Late times L, 2 D, 3 F, C, M, 3 Q, 6 J, R, 2?

95 Late times L, 2? D, 3 F, C, M, 3 Q, 6 J, R,

96 Critical path? L, 2 D, 3 F, C, M, 3 Q, 6 J, R,

97 Critical path, slack times L, 2 0 D, 3 F, C, M, 3 0 Q, 6 J, R,

98 Scheduling with Resource Constraints So far have assumed all resources required for project will be available. Q: Will they be available? What happens if they are not? 98

99 Scheduling with Resource Constraints: Resource Loading Resource Loading: amount of a specified resource required throughout a project Assume have a well-defined project Have defined the kinds of resources and amount or number of resources for every work package 99

100 Scheduling with Resource Constraints: Resource Loading Analysis -- apply to constrained resources Example: Work Package D resource requirements: Programmer 160 hrs. Systems Analyst 40 hrs. Mainframe Computer 10 hrs. Suppose Systems Analyst time and Mainframe Computer time, no problem. Hence, ignore these in resource loading analysis. Programmers are very busy and in short supply. Hence, focus on this in resource loading analysis 100

101 Scheduling with Resource Constraints: Resource Loading Analysis (cont d) Assume Work Package D must be completed in 2 weeks Each programmer can devote at most 20 hrs per week. Thus, the required programmers for Work Package D: 160 hrs 2 wks hrs = 80 hrs. 80 wk = 4 programmers wk hrs wk 20 programmer Work Package D will require 4 programmers for two weeks Similar estimates are made for number of programmers for every work package in the project 101

102 Scheduling with Resource Constraints: Project Network A E End B H Start C D Activity F G Immediate Predecessors Time (weeks) Resource (Programmers) A B C D E A 4 9 F C 2 7 G D, F 3 2 H B, G

103 Scheduling with Resource Constraints: Resource Loading Analysis Questions: According to the schedule, how many programmers will be needed each week for the project? Given the shortage of programmers, will there be enough programmers for the project? 103

104 Scheduling with Resource Constraints: Gantt Chart, early times According to the schedule, how many programmers will be needed each week for the project? A, 3 E, 9 B, 8 C, 6 F, 7 G, 2 H, 1 D, 4 e.g., Activity D requires 4 programmers Key: CP /57

105 Gantt Chart A, 3 E, 9 B, 8 C, 6 F, 7 G, 2 H, 1 D, Resource Loading Diagram Early Times For example, during weeks 1 and 2 F D 16 Activities A, B, C, and D are scheduled So, number of programmers needed is C F = 21 E 11 In week 3 G Activities E, B, and F are scheduled So, = 24 B E B 2 H 1 A G (Most project management software perform this kind of analysis) 105

106 Resource Leveling What happens if required resources exceed the available amount? Use resource leveling technique 106

107 Resource Leveling (cont d) D C 24 F E Resource Loading using Early Event Times 16 F G B E A B 2 G H week Suppose maximum number of programmers available for project in any given week = 12 The schedule is infeasible since weeks 1-4 require more than 12 programmers 107/57

108 Resource Leveling (cont d) Many activities are scheduled early in the project Not all of these have to be scheduled then They can be delayed Delaying activities defers need for resources 108

109 Use trial and error, delay activities along their slack ties, check impact on total required resources. *For example, delay A by 2 weeks B by 4 weeks E by 5 weeks A* E* B* C F G H D /57

110 Programmers Resource Leveling Viola! Project can be completed in 11 weeks with no more than 10 programmers per week B* C F G H D A* E* D A* B* E* C F G *Resource loading after rescheduling A, B, and E H 110

111 Resource Leveling (cont d) Method is called resource leveling because it results in leveling of peak requirements Notice in example, if constraint on programmers had been less than 10, project would not be able to complete project in 11 weeks D A* B* E* C F G H

112 Resource Leveling (cont d) When project has multiple constrained resources, Repeat same analysis for each All resources must be leveled simultaneously so no resource exceeds constraints This is one application in which project management software that is invaluable When PM does not have direct authority over resources Speak to managers of resources. Try to get suggestions about how to meet schedule with limited resources. 112

113 Tasks Multi-Project Scheduling Use similar approach to schedule multiple projects that share constrained resources Create resource loadings for projects scheduled at same time. Combined to yield multi-project loading. A B D C E Project A A B TimeD Project B C E F F Time 113

114 Multi-Project Scheduling Project A Project B If loading exceeds constraints, tasks within projects are delayed along their slack times. If that fails, then tasks in lower-priority projects are delayed further or (lower priority projects are delayed in their entirety) Software for multi-project planning and scheduling have this capability 114

115 Key Terms Activity Activity-on-arrow (AOA) Activity-on-node (AON) Burst activity Concurrent engineering Critical path Early and late times Free slack Gantt chart Hammock activity Lag relationship Merge activity Parallel activity Sensitivity Total slack 6 115

116 Greendale Stadium Case TABLE

SCHEDULE CREATION AND ANALYSIS. 1 Powered by POeT Solvers Limited

SCHEDULE CREATION AND ANALYSIS 1 www.pmtutor.org Powered by POeT Solvers Limited While building the project schedule, we need to consider all risk factors, assumptions and constraints imposed on the project