1. PROJECT MANAGEMENT week 5
Dr. Meryem Uluskan

2. Agenda Developing a Project Plan Developing the Project Network
From Work Package to Network
Constructing a Project Network
Activity-on-Node (AON) Fundamentals
Network Computation Process
Using the Forward and Backward Pass Information
Level of Detail for Activities
Practical Considerations
Extended Network Techniques

3. Developing the Project Network
The network
is developed from the information collected for the WBS
is a graphic flow chart of the project job plan
It depicts
the project activities,
the logical sequences,
the interdependencies of the activities, and
the times for the activities to start and finish along with the longest path through the network - the critical path.

4. Developing the Project Network
Network presents a graphic display of the flow and sequence of work through the project.
It provides the basis for scheduling labor and equipment.
It enhances communication and helps meeting the time, cost, and performance objectives of the project.
It provides an estimate of project duration.
It identifies “critical”activities and, therefore, should not be delayed if the project is to be completed as planned.
It highlights which activities to consider if the project needs to be compressed.
The project network represents three-quarters of the planning process.

5. From Work Package to Network
The project network is a visual flow diagram of the sequence, interrelationships, and dependencies of all the activities.
An activity is an element in the project that consumes time - for example, work or waiting.
Networks are built using nodes (boxes) and arrows (lines).
The node depicts an activity, and the arrow shows dependency and project flow.

6. From Work Package to Network
Integration of the WBS and project network is crucial to effective project management.

7. From Work Package to Network

8. From Work Package to Network

9. Constructing a Project Network
Terminology
Activity: an element of the project
that requires time, either while people work
or while people wait
Ex (wait). time waiting for contracts to be
signed, materials to arrive, budget clearance
Merge activity: an activity that has two or more preceding activities on which it depends.
Parallel (concurrent) activities: Activities that can take place
at the same time and can occur independently
if desired, not at the same time. A C B D

10. Constructing a Project Network
Path: a sequence of connected, dependent activities.
(chain of sequential activities)
Critical path: the longest path through the activity network that allows for the completion of all project-related activities;
shortest expected time in which the entire project can be completed.
delays on the critical path will delay completion of the entire project. D C A B
(Assumes that minimum of A + B > minimum of C in length of times to complete activities.)

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

12. Basic Rules to Follow in Developing Project Networks
Networks typically flow from left to right.
An activity cannot begin until all of its preceding activities are complete.
Arrows indicate precedence and flow and can cross over each other.
Identify each activity with a unique number; this number must be greater than its predecessors.
Looping is not allowed.
Conditional statements are not allowed.
Use common start and stop nodes.

13. Activity-on-Node (AON) Fundamentals
An activity is represented by a node (box).
The dependencies among activities are depicted by arrows.
The relationships can be found by answering the following three questions for each activity:
1. Which activities must be completed immediately before this activity? predecessor activities.
2. Which activities must immediately follow this activity?
successor activities.
3. Which activities can occur while this activity is taking place? concurrent or parallel relationship.

14. Activity-on-Node fundamentals
Activities Y and Z are parallel activities.
Parallel paths allow concurrent effort, which may shorten time to do a series of activities.

15. Activity-on-Node fundamentals
Accurate inclusion of all project activities, their dependencies, and time estimates are important.

16. Information for a simplified project network
The project represents a new business center that is to be developed
The work and services the county engineering design department must provide

17. Koll Business Center - Partial network
B, C, and D are all preceded by activity A.

18. Koll Business Center - Complete network

19. In Class Draw a project network. What activity(s) is a burst activity?
What activity(s) is a merge activity?

20. In Class

21. Activity-on-Node fundamentals
The addition of time to the network
allows us to estimate how long the project will take
allows us to determine
when activities can or must start,
when resources must be available,
which activities can be delayed, and
when the project is estimated to be complete
helps for early assessment of resource needs in terms of material, equipment, and people
In essence the project network with activity time estimates links planning, scheduling, and controlling of projects.

22. Network computation process
Activity time estimates are taken from the task times in the work package and added to the network
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)
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?
The longest path in the network which, when delayed, will delay the project.
How long can it be delayed? (slack or float—SL)

23. Network information
Activity time: workdays

24. Activity-on-Node network

25. Forward pass computation
1. You add activity times along each path in the network (ES + DUR = EF). 2. You carry the early finish (EF) to the next activity where it becomes its early start (ES), unless 3. The next succeeding activity is a merge activity. In this case you select the largest early finish number (EF) of all its immediate predecessor activities.

26. Activity-on-Node Network Forward Pass

27. 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.

28. Activity-on-Node network Backward pass

29. Determining Slack (or Float)
Total slack
The amount of time an activity can be delayed without delaying the entire project
The amount of time an activity can exceed its early finish date without affecting the project end date or an imposed completion date.
The difference between the LS and ES (LS - ES = SL) or between LF and EF (LF - EF = SL).
If slack of one activity in a path is used, the ES for all activities that follow in the chain will be delayed and their slack reduced.

30. Determining Slack (or Float)
The critical path can be identified as those activities that have a slack of zero
LF = EF or
LF - EF = 0 or LS - ES = 0
The critical path is the network path(s) that has (have) the least slack in common.
Ex: If the EF = 235 days, but the imposed LF or target date is 220 days,
all activities on the critical path would have a slack of minus 15 days.
means that a late start of 15 days for the first project activity
Negative slack occurs in practice when the critical path is delayed.

31. Sensitivity of a network
The likelihood the original critical path(s) will change once the project is initiated.
Function of:
The number of critical paths
The amount of slack across near critical activities
Insensitive network: has only one critical path and noncritical activities enjoy significant slack.
Sensitive network: has one or more critical paths and/or noncritical activities with very little slack.
The original critical path is much more likely to change once work gets under way.

32. Activity-on-Node network with slack
Delay of any of CP activities will delay the total project by the same number of days.

33. Sensitivity of Koll Business Center schedule
How sensitive is the Koll Business Center schedule?

34. Sensitivity of Koll Business Center schedule
Not very sensitive,
There is only one critical path
Each of the three noncritical activities have significant slack when compared to the estimated duration

35. Free Slack (Float)
The amount of time an activity can be delayed without delaying any immediately following (successor) activity.
Or the amount of time an activity can exceed its early finish date without affecting the early start date of any successor(s).
Can never be negative.

36. Free Slack Example

37. Determining slack (or float) - brief
Free slack (or float)
The amount of time an activity can be delayed without delaying connected successor activities
Total slack
The amount of time an activity can be delayed without delaying the entire project
Total slack is for the whole path
The critical path is the network path(s) that has (have) the least slack in common.

38. Using the Forward and Backward Pass Information
The ES and LF tell the time interval in which the activity should be completed.
Ex. Activity E (Staff report) must be completed within the interval workdays;
the activity can start as early as day 20 or finish as late as day 200.
Activity F (Commission approval), must start on day 20, or the project will be delayed.

39. Practical Considerations
Network logic errors
Activity numbering
Use of computers to develop networks
Calendar dates
Multiple starts and multiple projects

40. Practical Considerations Network Logic Errors
The network is not a decision tree; it is a project plan
“if test successful build proto, if failure redesign” are not permitted
Once a network plan is developed, it is an easy step to make revisions to accommodate changes

41. Practical Considerations Network Logic Errors
Looping is an attempt by the planner to return to an earlier activity.
The activity identification numbers should always be higher for the activities following an activity in question.
An activity should only occur once.
If an activity needs to occur again,
it should have a new name and identification number
should be placed in the right sequence on the network

42. Practical Considerations Network Logic Errors
Illogical Loop
The path would repeat itself.
Many computer programs catch this type of logic error.
Illogical Loop

43. Practical Considerations Activity Numbering
Each activity needs a unique identification code
usually a number
in ascending order
as simple as possible
gaps can be left between numbers (1, 5, 10, 15…)
so missing or new activities can be added later
Different designations such as:
numeric,
alphabetic,
combination designations
used to identify cost, work skill, departments, and locations.
can be used in activity numbering.

44. Practical Considerations Use of computers to develop networks
Air Control Project—Network Diagram

45. Practical Considerations Use of computers to develop networks
Air Control Project—Network Diagram
The project starts on January 1 and is planned to be finished February 14.

46. Air Control project (cont’d)
Early start Gantt chart

47. Practical Considerations cont’d.
Network logic errors
Activity numbering
Use of computers to develop networks
Calendar dates
Multiple starts and multiple projects

48. Practical Considerations Multiple starts and multiple projects
If a project network
begins with more than one activity or
ends with more than one activity;
These unconnected paths are called dangler paths.
Dangler paths give the impression that the project does not have a clear beginning or ending.
Tie dangler activities to a common project start or finish node.

49. The work breakdown structure (WBS)
The purpose of the WBS is to
logically designate broad tasks that include tasks from the task list,
identify subtasks, subsubtasks, etc.,
develop identifiers for the elements of the structure.
The tasks can be grouped in any number of ways:
by function,
by process phase,
by geography, etc.

50. The work breakdown structure (WBS)
The grouping is done hierarchically
The levels of the hierarchy don’t have to be grouped in the same way.
Logically group all those tasks you identified in doing the task list into broad tasks.
A broad task is a logical grouping of tasks.
A structured grouping of tasks into categories of broad tasks, subtasks, subsubtasks, etc. is called a work breakdown structure (WBS).

51. The work breakdown structure (WBS)
The WBS is a tree diagram of the task list and is displayed either in an outline format or an organizational-chart type format.
The WBS shows the relationships among individual tasks and gives structure to the task list.

52. The work breakdown structure (WBS)
The task list specifies the tasks, the estimate of the needed level of effort, and those tasks ending in a milestone.
In the WBS, we’re only interested in the tasks themselves.
The level of effort and milestone information from the task list will be used in other tools.
The information added at this step is the association or structural logic of the tasks from the task list.
For simple projects, only a few project divisions are required.
For complex projects, construct a detailed WBS.

53. The work breakdown structure (WBS)
Make sure you list all the broad tasks in the task list.
Break those tasks into subtasks.
Divide the tasks into as many subtasks as necessary to reduce tasks to manageable size.
Each subtask or sub-subtask should be small enough to control, but not so small it’s trivial.
Max. nine subtasks under a task or nine subsubtasks under a subtask, is OK.
Ten or more subtasks should be logically divided into two or more tasks.

54. The work breakdown structure (WBS)
Composing a good WBS is important, because
it’s the basis of the performance, or scope
constraint for the rest of the steps.
In this step you will use the tasks from your task list. And add groupings to the tasks.
In later tools, you’ll match the WBS against time, people, materials and equipment, funding, and specifications.

55. The work breakdown structure (WBS)
Definitions:
Broad task - Logical grouping of tasks.
Guidelines to create your WBS:
1. What are the primary broad tasks you need to accomplish?
2. What tasks, subtasks, sub-subtasks, etc. fall under each broad task?
List these tasks in an outline format (or organization-chart type format) to show broad tasks, subtasks, subsubtasks, etc.
3. Develop an identifying number for each broad task, subtask, and subsubtask by numbering the project 1. and the broad tasks 1.1, 1.2, etc. The tasks under broad task 1.1 are numbered 1.1.1, 1.1.2, etc. Use this scheme for numbering all entries in your WBS.

56. The work breakdown structure (WBS)
Helpful Hints:
List major categories of tasks first, then subtasks.
Use short identifiers with task numbers.
Modify the task list as needed.
Make sure you don't have more than nine subtasks in a task, nine subsubtasks in a subtask, etc.

57. WBS
WBS organizes tasks into related groups

58. WBS for Mary’s House

59. The milestone log
Highlights important events, deliverables and other task ends
The activities of a project show input to the system. The events related to the activities show physical evidence and output from the system.
Together, an activity and its associated event make up a task.
Events the project manager wants to highlight and track are milestones.

60. The milestone log Milestones are
events you wish to highlight and follow.
events that have clear results or ending points.
events that are significant; they give you a feel for whether or not you’re on schedule.
events that should not be more than 10 days apart.

61. The milestone log
The milestone log contains more detailed milestone information such as
the responsible people,
event descriptions, and
due dates.
All milestones are characterized by physical evidence.

62. The milestone log

63. The milestone log
A crucial part of monitoring milestones is keeping track of the milestone due dates in terms of the
planned due date,
the actual completion date, and
the difference between the two (variance).
Completion of milestones for preceding tasks will affect succeeding tasks.
Therefore, a more complete milestone log would include planned and actual completion dates (due dates) and the variance.

64. The milestone log
Guidelines for creating a milestone log. 1. What are the milestones from your task list? List them in sequential order. 2. What physical evidence shows the milestone is reached? Describe it. 3. Who’s responsible for the milestone? 4. When is it due? Record the responsible person and the due date in the corresponding columns.

65. The milestone log
Helpful Hints: • Project deliverables should be creative and should meet customer needs and wants. • Project deliverables should be visible and should facilitate communication. • Have the task list handy for reference. • Check to see if the schedule contains time periods greater than ten days without a milestone.

66. The milestone log – Mary’s house

67. The milestone log with actual dates

68. Next deliverables- WBS

69. Next deliverables- The milestone log