PM

1. PROJECT MANAGEMENT
TIME MANAGEMENT TECHNIQUES
Presented by:
Piyush Agarwal
2015MB22

2. Completing a project on time and within budget is not an
easy task. The project scheduling phase plays a central role
in predicting both the time and cost aspects of a project.
More precisely, it determines a timetable in order to be
able to predict the expected time and cost of each
individual activity.
ABSTRACT

3. Introduction
• What is the expected project finish date?
• How can precedence relations between activities be
modeled in a network?
• What are the expected activity start and finish times?
• What is the effect of variability in activity time
estimates on the project duration?

4. Project Definition Phase
• In the definition phase of a project’s life cycle, the organization defines the
project objectives, the project specifications and requirements and the
organization of the entire project. In doing so, the organization decides on how
it is going to achieve all project objectives.
• The Work Breakdown Structure (WBS) is a fundamental concept of the
definition phase that, along with the Organizational Breakdown Structure (OBS),
identifies the set of activities needed to achieve the project goal as well as the
responsibilities of the project team for the various subparts of the project.
• This information needs to be transformed into a network diagram that identifies
a list of project activities and the technological links with the other activities.
This project network is an easy and accessible tool for the critical path
calculations to determine the earliest and latest activity start times of the
scheduling phase.

5. WBS and OBS
• The preparation of a Work Breakdown Structure (WBS) is an important step in
managing and mastering the inherent complexity of the project. It involves the
decomposition of major project deliverables into smaller, more manageable
components until the deliverables are defined in sufficient detail to support
development of project activities (PMBOK 2004).
• The WBS is a tool that defines the project and groups the project’s discrete
work elements to help organize and define the total work scope of the project.
It provides the necessary framework for detailed cost estimation and control
along with providing guidance for schedule development and control. Each
descending level of the WBS represents an increased level of detailed definition
of the project work.

8. Network Analysis
• To construct a complete and detailed WBS, the work packages of a WBS need to be
further subdivided into activities.
• It might improve the level of detail and accuracy of cost, duration and resource
estimates which serve as inputs for the construction of a project network and
scheduling phase.
• The definition phase, which determines the list of activities, the precedence relations,
possible resource requirements and the major milestones of the project, is different
from the scheduling phase in the level of detail and the timing of project activities.
• The scheduling phase aims at the determination of start and finish times of each activity
of the project, and consequently, determines the milestones in detail. This can only be
done after the construction of the network in the definition phase.
• Incorporating these technological links between any pair of activities is a first step in the
construction of the project network. A network consists of nodes and arcs and
incorporates all the activities and their technological precedence relations. A network
can be seen as a graph G(N, A) where the set N is used to denote the set of nodes and A
to denote the set of arcs. The network has a single start node and a single end node and
is used as an input for the scheduling phase

9. 9
Project Network
• Network analysis is the general name given to certain specific
techniques which can be used for the planning, management and
control of projects
■ Use of nodes and arrows
Arrows  An arrow leads from tail to head directionally
– Indicate ACTIVITY, a time consuming effort that is required to
perform a part of the work.
Nodes  A node is represented by a circle
- Indicate EVENT, a point in time where one or more activities start
and/or finish.
• Activity
– A task or a certain amount of work required in the project
– Requires time to complete
– Represented by an arrow
• Dummy Activity
– Indicates only precedence relationships
– Does not require any time of effort

10. 10
■ Event
– Signals the beginning or ending of an activity
– Designates a point in time
– Represented by a circle (node)
■ Network
– Shows the sequential relationships among activities
using nodes and arrows
Activity-on-node (AON)
nodes represent activities, and arrows show precedence
relationships
Activity-on-arrow (AOA)
arrows represent activities and nodes are events for points in
time
Project Network

11. • One type is the activity-on-arc (AOA) project network, where each activity is represented by an arc. A
node is used to separate an activity (an outgoing arc) from each of its immediate predecessors (an
incoming arc). The sequencing of the arcs thereby shows the precedence relationships between the
activities.
• The second type is the activity-on-node (AON) project network, where each activity is represented by
a node. The arcs then are used just to show the precedence relationships between the activities. In
particular, the node for each activity with immediate predecessors has an arc coming in from each of
these predecessors.

12. darla/smbs/vit 12
AOA Project Network for House
3
2 0
1
3
1 1
1
1 2 4 6 7
3
5
Lay
foundation
Design house
and obtain
financing
Order and
receive
materials
Dummy
Finish
work
Select
carpet
Select
paint
Build
house
AON Project Network for House
1
3
2
2
4
3
3
1 5
1
6
1
7
1
Start
Design house and
obtain financing
Order and receive
materials
Select paint
Select carpet
Lay foundations Build house
Finish work

13. 13
Situations in network diagram
A
B
C
A must finish before either B or C can start
A
B
C both A and B must finish before C can start
D
C
B
A
both A and C must finish before either of B
or D can start
A
C
B
D
Dummy
A must finish before B can start
both A and C must finish before D can start

14. My word.....
My purpose here is to give a few ideas about PERT , CPM
& other project management tools for entrepreneurs .
These are introductory ideas. Be an Entrepreneur, change
the society, change the world. Go with positive spirit.
Please pass this presentation to all those who might need
it. Let us spread knowledge as widely as possible. I
welcome your suggestions. I also request you to help me
in spreading social entrepreneurship across the globe –
for which I need support of you people – not of any VIP.
With your help, I can spread the ideas – for which we
stand....

15. 15
History of CPM/PERT
■ Critical Path Method (CPM)
– E I Du Pont de Nemours & Co. (1957) for construction
of new chemical plant and maintenance shut-down
– Deterministic task times
– Activity-on-node network construction
– Repetitive nature of jobs
■ Project Evaluation and Review Technique (PERT)
– U S Navy (1958) for the POLARIS missile program
– Multiple task time estimates (probabilistic nature)
– Activity-on-arrow network construction
– Non-repetitive jobs (R & D work)

16. What is CPM ?
■ Critical Path Method = here we try to identify the
critical path for completion of a project. Cricial = very
important
■ When we are implementing a project, we are doing
a series of activities, which are called project. There
are many ways to do a project. In CPM, we try to pick
up the path which consists of all the activities which
cannot be delayed. This path requires greater
attention.

17. Why is CPM more important ?
■ If an activity is on CPM, it cannot be delayed. Other
activities can be delayed, but the activities on CPM
cannot be delayed. Delay of one day will delay the
project.

18. What is SLACK?
■You can delay other activities (other than Critical Path activities ).
–Thus there is slack (means you can delay some activities ).
■ Slack denotes flexibility / freedom / ease on the part of those
implementing the project

19. What is PERT ?
■ PERT = project evaluation and review technique
■ Here we try to look at each activity and try to find
out expected time to complete the project.

20. What is the difference between
PERT & CPM?
■ PERT gives us the best possible estimate of doing
the project ( in time).
■ CPM tells us about activities which are critical
(delay in these activities will delay the project

21. Network example
Illustration of network analysis of a minor redesign of a product and
its associated packaging.
The key question is: How long will it take to complete this project ?

22. For clarity, this list is kept to a minimum by specifying only
immediate relationships, that is relationships involving activities
that "occur near to each other in time".

23. darla/smbs/vit
Questions to prepare activity network
■ Is this a Start Activity?
■ Is this a Finish Activity?
■ What Activity Precedes this?
■ What Activity Follows this?
■ What Activity is Concurrent with this?

24. CPM calculation
■ Path
– A connected sequence of activities leading from the starting
event to the ending event
■ Critical Path
– The longest path (time); determines the project duration
■ Critical Activities
– All of the activities that make up the critical path

25. Forward Pass
■ Earliest Start Time (ES)
– earliest time an activity can start
– ES = maximum EF of immediate predecessors
■ Earliest finish time (EF)
– earliest time an activity can finish
– earliest start time plus activity time
EF= ES + t
Latest Start Time (LS)
Latest time an activity can start without delaying critical path
time
LS= LF - t
Latest finish time (LF)
latest time an activity can be completed without delaying
critical path time
LS = minimum LS of immediate predecessors
Backward Pass

26. CPM analysis
■ Draw the CPM network
■ Analyze the paths through the network
■ Determine the float for each activity
– Compute the activity’s float
float = LS - ES = LF - EF
– Float is the maximum amount of time that this
activity can be delay in its completion before it
becomes a critical activity, i.e., delays completion of
the project
■ Find the critical path is that the sequence of activities
and events where there is no “slack” i.e.. Zero slack
– Longest path through a network
■ Find the project duration is minimum project completion
time

27. CPM Example:
■ CPM Network
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17 h, 9
i, 6
j, 12

28. CPM Example
■ ES and EF Times
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17 h, 9
i, 6
j, 12
0 6
0 8
0 5

29. CPM Example
■ ES and EF Times
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17 h, 9
i, 6
j, 12
0 6
0 8
0 5
5 14
8 21
6 23
6 21

30. CPM Example
■ ES and EF Times
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17 h, 9
i, 6
j, 12
0 6
0 8
0 5
5 14
8 21 21 33
6 23
21 30
23 29
6 21
Project’s EF = 33

31. CPM Example
■ LS and LF Times
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17
h, 9
i, 6
j, 12
0 6
0 8
0 5
5 14
8 21
21 33
6 23
21 30
23 29
6 21
21 33
27 33
24 33

32. CPM Example
■ LS and LF Times
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17
h, 9
i, 6
j, 12
0 6
0 8
0 5
5 14
8 21
21 33
6 23
21 30
23 29
6 21
4 10
0 8
7 12
12 21
21 33
27 33
8 21
10 27
24 33
18 24

33. CPM Example
■ Float
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17
h, 9
i, 6
j, 12
0 6
0 8
0 5
5 14
8 21 21 33
6 23
21 30
23 29
6 21
3 9
0 8
7 12
12 21
21 33
27 33
8 21
10 27
24 33
9 24
3 4
3
3
4
0
0
7
7
0

34. CPM Example
■ Critical Path
a, 6
f, 15
b, 8
c, 5
e, 9
d, 13
g, 17 h, 9
i, 6
j, 12

35. darla/smbs/vit
PERT
■ PERT is based on the assumption that an activity’s
duration follows a probability distribution instead of
being a single value
■ Three time estimates are required to compute the
parameters of an activity’s duration distribution:
– pessimistic time (tp ) - the time the activity would
take if things did not go well
– most likely time (tm ) - the consensus best estimate
of the activity’s duration
– optimistic time (to ) - the time the activity would
take if things did go well
Mean (expected time): te =
tp + 4 tm + to
6
Variance: Vt = 2 =
tp - to
6
2

36. PERT analysis
■ Draw the network.
■ Analyze the paths through the network and find the
critical path.
■ The length of the critical path is the mean of the project
duration probability distribution which is assumed to be
normal
■ The standard deviation of the project duration probability
distribution is computed by adding the variances of the
critical activities (all of the activities that make up the
critical path) and taking the square root of that sum
■ Probability computations can now be made using the
normal distribution table.

37. Probability computation
Determine probability that project is completed within specified time
Z =
x - 

where  = tp = project mean time
 = project standard mean time
x = (proposed ) specified time

38. Normal Distribution of Project Time
 = tp Time
x
Z
Probability

39. PERT Example
Immed. Optimistic Most Likely Pessimistic
Activity Predec. Time (Hr.) Time (Hr.) Time (Hr.)
A -- 4 6 8
B -- 1 4.5 5
C A 3 3 3
D A 4 5 6
E A 0.5 1 1.5
F B,C 3 4 5
G B,C 1 1.5 5
H E,F 5 6 7
I E,F 2 5 8
J D,H 2.5 2.75 4.5
K G,I 3 5 7

40. PERT Example
A
D
C
B
F
E
G
I
H
K
J
PERT Network

41. PERT Example
Activity Expected Time Variance
A 6 4/9
B 4 4/9
C 3 0
D 5 1/9
E 1 1/36
F 4 1/9
G 2 4/9
H 6 1/9
I 5 1
J 3 1/9
K 5 4/9

42. PERT Example
Activity ES EF LS LF Slack
A 0 6 0 6 0
*critical
B 0 4 5 9
5
C 6 9 6 9 0 *
D 6 11 15 20 9
E 6 7 12 13 6
F 9 13 9 13
0 *
G 9 11 16 18 7
H 13 19 14 20
1

43. PERT Example
Vpath = VA + VC + VF + VI + VK
= 4/9 + 0 + 1/9 + 1 + 4/9
= 2
path = 1.414
z = (24 - 23)/(24-23)/1.414 = .71
From the Standard Normal Distribution table:
P(z < .71) = .5 + .2612 = .7612

44. Project Crashing
■ Crashing
– reducing project time by expending additional
resources
■ Crash time
– an amount of time an activity is reduced
■ Crash cost
– cost of reducing activity time
■ Goal
– reduce project duration at minimum cost

45. Activity crashing
Activity time
Crashing activity
Crash
time
Crash
cost
Normal Activity
Normal
time
Normal
cost
Slope = crash cost per unit time

46. Time-Cost Relationship
 Crashing costs increase as project duration decreases
 Indirect costs increase as project duration increases
 Reduce project length as long as crashing costs are less than
indirect costs
Time-Cost Tradeoff
time
Direct cost
Indirect
cost
Total project cost
Min total cost =
optimal project
time

47. Project Crashing example
1
12
2
8
4
12
3
4 5
4
6
4
7
4

48. Time Cost data
Activity Normal
time
Normal
cost Rs
Crash
time
Crash
cost Rs
Allowable
crash time
slope
1
2
3
4
5
6
7
12
8
4
12
4
4
4
3000
2000
4000
50000
500
500
1500
7
5
3
9
1
1
3
5000
3500
7000
71000
1100
1100
22000
5
3
1
3
3
3
1
400
500
3000
7000
200
200
7000
75000 110700

49. 1
12
2
8
3
4 5
4
6
4
7
4
R400
R500
R3000
R7000
R200
R200
R700
12
4
Project duration = 36
From…..
To…..
1
7
2
8
3
4 5
4
6
4
7
4
R400
R500
R3000
R7000
R200
R200
R700
12
4
Project
duration = 31
Additional cost
= R2000

50. Benefits of CPM/PERT
■ Useful at many stages of project management
■ Mathematically simple
■ Give critical path and slack time
■ Provide project documentation
■ Useful in monitoring costs
•How long will the entire project take to be completed? What are the
risks involved?
•Which are the critical activities or tasks in the project which could
delay the entire project if they were not completed on time?
•Is the project on schedule, behind schedule or ahead of schedule?
•If the project has to be finished earlier than planned, what is the best
way to do this at the least cost?
CPM/PERT can answer the following important
questions:

51. Limitations to CPM/PERT
■ Clearly defined, independent and stable activities
■ Specified precedence relationships
■ Over emphasis on critical paths
■ Deterministic CPM model
■ Activity time estimates are subjective and depend on
judgment
■ PERT assumes a beta distribution for these time estimates,
but the actual distribution may be different
■ PERT consistently underestimates the expected project
completion time due to alternate paths becoming critical
To overcome the limitation, Monte Carlo simulations can be
performed on the network to eliminate the optimistic bias

52. Computer Software
for Project Management
■ Microsoft Project (Microsoft Corp.)
■ MacProject (Claris Corp.)
■ PowerProject (ASTA Development Inc.)
■ Primavera Project Planner (Primavera)
■ Project Scheduler (Scitor Corp.)
■ Project Workbench (ABT Corp.)

53. Gantt Charts
• The Gantt chart is named after its originator Henry Gantt and displays a
timetable for each activity of the project. Each activity is shown as a
block or bar and drawn to scale in time. The timescale is usually drawn
horizontally while the different activities are displayed on the vertical
axis.
• This chart is used for scheduling and is often used in conjunction with
the project network to show the technological dependencies between
activities.
• The bars represent the earliest start and finish times of each activity of
the example project. The gray lines following the activity bars represent
the activity slack, and hence, shifting activities towards the end of these
gray bars results in the corresponding LSS. Activities without slack (i.e.
activities 1, 3, 5, 10, 12, 13 and 14) belong to the critical path and need
the attention of the project manager.

59. All The best