Lecture 6

Chapter 6:Chapter 6:
Project Time ManagementProject Time Management
Information TechnologyInformation Technology
Project Management, SixthProject Management, Sixth
EditionEdition
Note: See the text itself for full citations.

Information Technology Project
Management, Sixth Edition
Importance of Project Schedules
2
Managers often cite delivering projects on time as one of their
biggest challenges.
Time has the least amount of flexibility; it passes no matter what
happens on a project.
Schedule issues are the main reason for conflicts on projects,
especially during the second half of projects

Project Time Management Processes
3
Define activities: identifying the specific activities that the project team
members and stakeholders must perform to produce the project deliverables.
Sequence activities: identifying and documenting the relationships
between project activities.
Estimate activity durations: estimating the number of work periods
that are needed to complete individual activities.
Develop the schedule: analyzing activity sequences, activity resource
estimates, and activity duration estimates to create the project schedule.
Control the schedule: controlling and managing changes to the project
schedule

Defining Activities
4
An activity or task is an element of work normally found
on the work breakdown structure (WBS) that has an
expected duration, a cost, and resource requirements.
Activity definition involves developing a more detailed
WBS and supporting explanations to understand all the
work to be done so you can develop realistic cost and
duration estimates

Activity Lists and Attributes
5
An activity list is a tabulation of activities to be
included on a project schedule that includes following
attributes:
The activity name
An activity identifier or number
A brief description of the activity
The goal of this process is to ensure that the project
team has the complete understanding of all the work
they must do as part of the project scope.

Milestones
6
A milestone is a significant event that normally has no
duration.
It often takes several activities and a lot of work to complete
a milestone.
They’re useful tools for setting schedule goals and
monitoring progress.
Examples include obtaining customer sign-off on key
documents or completion of specific products

Sequencing Activities
7
Involves reviewing activities and determining
dependencies.
A dependency or relationship shows the sequence of
project activities. For example, does a certain activity
have to be finished before another one can start, can
several activities be done in parallel, etc.
You must determine dependencies in order to use critical
path analysis.

Three types of Dependencies
8
Mandatory dependencies: inherent in the nature of the
work being performed on a project, sometimes referred to
as hard logic . e.g you can’t test until after the code is written
Discretionary dependencies: defined by the project team;
sometimes referred to as soft logic and should be used with
care since they may limit later scheduling options. e.g good
practice is to not start detailed design until the users sign off on all of the
analysis work.
External dependencies: involve relationships between
project and non-project activities.
 installation of new operating system and other sw depends on delivery of new hw from
 an external supplier.

Network Diagrams
9
Network diagrams are the preferred technique for showing
activity sequencing.
A network diagram is a schematic display of the logical
relationships among, or sequencing of, project activities.
Two main formats are the ADM or AOA and PDM.

Figure 6-2. Sample Activity-on-Arrow (AOA)
Network Diagram for A Project
10

Arrow Diagramming Method (ADM or
AOA)
11
Also called activity-on-arrow (AOA) network diagrams.
Activities are represented by arrows.
Nodes or circles are the starting and ending points of
activities.
Can only show finish-to-start dependencies.

Process for Creating AOA Diagrams
12
1. Find all of the activities that start at node 1. Draw their finish nodes and
draw arrows between node 1 and those finish nodes. Put the activity letter or
name and duration estimate on the associated arrow.
2. Continue drawing the network diagram, working from left to right. Look for
bursts and merges. Bursts occur when a single node is followed by two or
more activities. A merge occurs when two or more nodes precede a single
node.
3. Continue drawing the project network diagram until all activities are
included on the diagram that have dependencies.
4. all arrowheads should face toward the right, and no arrows should cross on
an AOA network diagram.

Figure 6-2. Sample Tabular Diagram of AOA
for A Project
13
Activity Start Node End Node Duration
A 1 2 1
B 1 3 2
C 1 4 3
D 2 5 4
..

Precedence Diagramming Method
(PDM)
14
Activities are represented by boxes.
Arrows show relationships between activities.
More popular than ADM method and used by project
management software.
Better at showing different types of dependencies

Figure 6-4. Sample PDM Network Diagram
15

Activity Duration Estimating
16
One of the important considerations in making duration
estimates is the availability of resources.
People, equipment, skill level, no. of people
Duration includes the actual amount of time worked on
an activity or elapsed time.
Effort is the number of workdays or work hours required
to complete a task.
Effort does not normally equal duration.

Three-Point Estimates
17
Instead of providing activity estimates as a discrete number,
such as four weeks, it’s often helpful to create a three-point
estimate
An estimate that includes an optimistic, most likely, and
pessimistic estimate, such as three weeks for the optimistic,
four weeks for the most likely, and five weeks for the
pessimistic estimate
PERT is based on three point estimation of duration.

Program Evaluation and Review
Technique (PERT)
18
PERT is a network analysis technique used to estimate
project duration when there is a high degree of uncertainty
about the individual activity duration estimates
PERT uses probabilistic time estimates
Duration estimates based on using optimistic, most likely,
and pessimistic estimates of activity durations.

PERT Formula and Example
19
PERT weighted average =
optimistic time + 4X most likely time + pessimistic time
6
Example:
PERT weighted average =
8 workdays + 4 X 10 workdays + 24 workdays = 12 days
6
where optimistic time = 8 days
most likely time = 10 days, and
pessimistic time = 24 days
Therefore, you’d use 12 days on the network diagram instead of 10
when using PERT for the above example

Developing the Schedule
20
Uses results of the other time management processes to
determine the start and end date of the project
Ultimate goal is to create a realistic project schedule that
provides a basis for monitoring project progress for the time
dimension of the project
Important tools and techniques include Gantt charts, critical
path analysis

Gantt Charts
21
Gantt charts provide a standard format for displaying project
schedule information by listing project activities and their
corresponding start and finish dates in a calendar format
On the left of the chart is a list of the activities and along the top is a
suitable time scale
Each activity is represented by a bar
the position and length of the bar reflects the start date, duration and
end date of the activity

Gantt Charts (Continue)
22
Sample Gantt Chart

Gantt Charts (Continue)
23
Gantt Chart allows to view
 What the various activities are
 When each activity begins and ends
 How long each activity is scheduled to last
 Where activities overlap with other activities, and by how much
 The start and end date of the whole project
To summarize, a Gantt chart shows you what has to be done (the activities) and when
(the schedule).

Figure 6-5. Gantt Chart for a Project
24
Note: Darker bars would be red in Project 2007 to represent critical tasks.

Figure 6-6. Gantt Chart for Software Launch
Project
25

Figure 6-8. Determining the Critical Path for A
Project
26

Critical Path Method (CPM)
27
 The critical path is the longest path through the network diagram and has
the least amount of slack or float.
 Slack or float is the amount of time an activity may be delayed without
delaying a succeeding activity or the project finish date.
 CPM is a network diagramming technique used to predict total project
duration.
 A critical path for a project is the series of activities that determines the
earliest time by which the project can be completed.
 There can be more than one critical path if the lengths of two or more paths are the
same
 The critical path can change as the project progresses

Calculating Early and Late Start
and Finish Dates
28
 Slack or float is the amount of time an activity may be delayed without
delaying a succeeding activity or the project finish date.
Task Dependency Early
Start
Duration Early
Finish
Late Start Late Finish
A --- 01-02 5 05-02 05-02 10-02
B --- 01-02 10 10-02 01-02 10-02
C A,B 10-02 7 17-02 10-02 17-02

Calculating Early and Late Start
and Finish Dates
29

How to Find the Critical Path
30
To find the critical path, need to determine the following quantities
for each activity in the network
1.1. Earliest start timeEarliest start time (ESES): the earliest time an activity can begin
without violation of immediate predecessor requirements
2.2. Earliest finish timeEarliest finish time (EFEF): the earliest time at which an activity can
end
3.3. Latest start timeLatest start time (LSLS): the latest time an activity can begin without
delaying the entire project
4.4. Latest finish timeLatest finish time (LFLF): the latest time an activity can end without
delaying the entire project

31
In the nodes, the activity time and the early and late start and finish times
are represented in the following manner
Earliest times are computed as
Earliest finish time = Earliest start time
+ Expected activity time
Earliest start = Largest of the earliest finish times of
immediate predecessors
ES = Largest EF of immediate predecessors
EF = ES + t
ACTIVITY t
ES EF
LS LF

 At the start of the project we set the time to zero
 Thus ES = 0 for both A and B
Start
A t = 2
ES = 0 EF = 0 + 2 = 2
B t = 3
ES = 0 EF = 0 + 3 = 3

33
Task Dependency Duration
A -- 2
B -- 3
C A 2
D B 4
E C 4
F C 3
G D,E 5
H F,G 2

Steps for Calculating the Critical Path
34
First develop a good network diagram
Add the duration estimates for all activities on each path
through the network diagram
The longest path is the critical path
If one or more of the activities on the critical path takes
longer than planned, the whole project schedule will slip
unless the project manager takes corrective action

 General Foundry’s ES and EF times
A 2
0 2
C 2
2 4
H 2
13 15
E 4
4 8
B 3
0 3
D 4
3 7
G 5
8 13
F 3
4 7
Start Finish
Figure 13.4
ACTIVITY t
ES EF
LS LF

 Latest times are computed as
Latest start time =
Latest finish time
– Expected activity time
LS = LF – t
Latest finish time = Smallest of latest start times
for following activities
LF = Smallest LS of following activities
 For activity H
LS = LF – t = 15 – 2 = 13 weeks

 General Foundry’s LS and LF times
A 2
0 2
0 2
C 2
2 4
2 4
H 2
13 15
13 15
E 4
4 8
4 8
B 3
0 3
1 4
D 4
3 7
4 8
G 5
8 13
8 13
F 3
4 7
10 13
Start Finish
Figure 13.5 LS = LF – t
LF =Smallest LS of following activities
ACTIVITY t
ES EF
LS LF

 Once ES, LS, EF, and LF have been determined, it is a simple matter to find the
amount of slack timeslack time that each activity has
Slack = LS – ES, or Slack = LF – EF
 FromTable 13.3 we see activities A, C, E, G, and H have no slack time
 These are called critical activitiescritical activities and they are said to be on the critical pathcritical path
 The total project completion time is 15 weeks
 Industrial managers call this a boundary timetable

 General Foundry’s schedule and slack times
ACTIVITY
EARLIEST
START,
ES
EARLIEST
FINISH,
EF
LATEST
START,
LS
LATEST
FINISH,
LF
SLACK,
LS – ES
ON CRITICAL
PATH?
A 0 2 0 2 0 Yes
B 0 3 1 4 1 No
C 2 4 2 4 0 Yes
D 3 7 4 8 1 No
E 4 8 4 8 0 Yes
F 4 7 10 13 6 No
G 8 13 8 13 0 Yes
H 13 15 13 15 0 Yes
Table 13.3

 General Foundry’s critical path
A 2
0 2
0 2
C 2
2 4
2 4
H 2
13 15
13 15
E 4
4 8
4 8
B 3
0 3
1 4
D 4
3 7
4 8
G 5
8 13
8 13
F 3
4 7
10 13
Start Finish
Figure 13.6

Assignment
41

Techniques to Shorten a Project
Schedule
42
Explain Project Cost Management Processes by giving detail for the
following areas:
1. Resource Planning
2. Estimating costs
3. Determining the budget
4. Controlling costs

43

44
Crashing : It is the process by which duration of project is reduced
by INCREASING the amount of RESOURCES allocated
FastTracking : In fast tracking, activities that were planned to be
performed in sequential order are rescheduled to be performed in
parallel or partially in parallel
Disadvantage is that starting some tasks too soon often increases
project risk and results in rework.

Using Critical Path Analysis to Make Schedule
Trade-offs
45
Free slack or free float is the amount of time an activity can be
delayed without delaying the early start of any immediately
following activities.
Total slack or total float is the amount of time an activity may be
delayed from its early start without delaying the planned project
finish date.

Table 6-1. Free and Total Float or Slack
for Project X
46

Controlling the Schedule
47
Goals are to know the status of the schedule, identify factors that
cause schedule changes, determine that the schedule has changed,
and manage changes when they occur.
Tools and techniques include:
Progress reports
A schedule change control system
Project management software, including schedule comparison
charts like the tracking Gantt chart
Variance analysis, such as analyzing float or slack
Performance management, such as earned value (Chapter 7)

Reality Checks on Scheduling
48
First review the draft schedule or estimated completion date in
the project charter.
Prepare a more detailed schedule with the project team and get
stakeholder’s approval.
To establish the schedule it is critical to get involvement and
commitment from all project team members, upper
management, the customer, and other key stakeholders.
Conduct of progress meetings with stakeholders.
Alert top management well in advance if there are schedule problems.

Working with People Issues
49
Strong leadership helps projects succeed more than good
PERT charts.
Project managers should use:
Empowerment
Incentives
Discipline
Negotiation

Schedule Control Suggestions
50
Perform reality checks on schedules
Don’t plan for everyone to work at 100% capacity all the
time.
Hold progress meetings with stakeholders and be clear and
honest in communicating schedule issues

Chapter Summary
51
Project time management is often cited as the main source of
conflict on projects, and most IT projects exceed time estimates
Main processes include:
Define activities
Sequence activities
Estimate activity resources
Estimate activity durations
Develop schedule
Control schedule

Lecture 6

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