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RMK 252 – PRINCIPLES OF

PROJECT MANAGEMENT

PROJECT MANAGEMENT TECHNIQUES TOOLS

-BAR CHARTS, ARROW DIAGRAM CRITICAL PATH METHOD

MARCH 6

TH

2008

  ARMAN ABDUL RAZAK

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WHY THE NEED FOR PM TECHNIQUES & TOOLS?

faster comprehension of data;

easier interface for control and

monitoring;

better representation of analyzed

facts and figures; entire framework/outline of the

project can be viewed easier.

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BAR CHARTS

 A bar chart, also known as a bar graph, is a chart with

rectangular bars of lengths proportional to that value that they

represent. Bar charts are used for comparing two or more

values. The bars can be horizontally or vertically oriented.

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HISTOGRAMS

 A histogram is a graphical display of tabulated frequencies. A histogram isthe graphical version of a table that shows what proportion of cases fall

into each of several or many specified categories. The histogram differs

from a bar chart in that it is the area of the bar that denotes the value, not

the height, a crucial distinction when the categories are not of uniformwidth. The categories are usually specified as non-overlapping intervals of

some var iab le . The categor ies or bars must be ad jacent .

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PARETO CHART

 A Pareto chart is a special type of bar chart where the values beingplotted are arranged in descending order. The graph is accompanied by a

line graph which shows the cumulative totals of each category, left to

right.

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ARROW DIAGRAM

 Also called: activity network diagram, network diagram, activitychart, node diagram, CPM (critical path method) chart

Variation: PERT (program evaluation and review technique)

chart

The arrow diagram shows the required order of tasks in a project orprocess, the best schedule for the entire project, and potential

scheduling and resource problems and their solutions. The arrow

diagram lets you calculate the “critical path” of the project. This is the

flow of critical steps where delays will affect the timing of the entireproject and where addition of resources can speed up the project.

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ARROW DIAGRAM

When to Use an Arrow Diagram

When scheduling and monitoring tasks within a complex

project or process with interrelated tasks and resources.

When you know the steps of the project or process, their

sequence and how long each step takes.

When project schedule is critical, with serious

consequences for completing the project late or

significant advantage to completing the project early.

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ARROW DIAGRAM

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ARROW DIAGRAM

Start

Finish

Conductinterviews

Investigate

other 

systems

 Analyse

requirements

Investigatepackages

Investigate

hardware

Producereport

Network diagram (activity-on-arrow format)

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Start

Finish

Conductinterviews

Investigate

other 

systems

 Analyse

requirements

Investigatepackages

Investigate

hardware

Producereport

8

4

3

8

5

5

CRITICAL PATH

METHOD (CPM)

Network diagram with durations & critical path added

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The CPM Diagram

• “ Tasks” are Arrows • “ Events” are Circles

• “ Dummy Tasks” are Dashed Arrows

• “ Critical Tasks” are Thick Arrows

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CRITICAL PATH

METHOD (CPM)

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1. Specify the Individual Activit ies: From the work breakdown structure, a listing

can be made of all the activities in the project. This listing can be used as the basis

for adding sequence and duration information in later steps

2. Determine the Sequence of the Activities: Some activities are dependent onthe completion of others. A listing of the immediate predecessors of each activity is

useful for constructing the CPM network diagram.

3. Draw the Network Diagram: Once the activities and their sequencing have

been defined, the CPM diagram can be drawn. CPM originally was developed asan activity on node (AON) network, but some project planners prefer to specify the

activities on the arcs.

4. Estimate Activity Completion Time: The time required to complete each

activity can be estimated using past experience or the estimates of knowledgeable

persons. CPM is a deterministic model that does not take into account variation in

the completion time, so only one number is used for an activity's time estimate

5. Identi fy the Critical Path: The critical path is the longest-duration path through

the network. The significance of the critical path is that the activities that lie on it

cannot be delayed without delaying the project. Because of its impact on the entireproject, critical path analysis is an important aspect of project planning

CRITICAL PATH

METHOD (CPM)

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The critical path can be identified by determining the four parameters for

each activity. The four parameters are Earliest Start, Earliest Finish, Latest

Finish and Latest Start.

Earliest Start: The earliest time at which the activity can start given that its

precedent activities must be completed first.

Earliest Finish: This is equal to the earliest start time for the activity plus the

time required to complete the activity i.e. Earliest Start + Duration

Latest Finish: The latest time at which the activity can be completed without

delaying the project.

Latest Start: It is equal to the latest finish time minus the time required to

complete the activity i.e.Latest Finish - Duration

CRITICAL PATH

METHOD (CPM)

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Critical Path: The critical path is the path through the project network in which none

of the activities have slack, that is, the path for which ES=LS and EF=LF for all

activities in the path.

Dummy arrows are used where required to avoid giving the same numbering to two

activities as one of the rules for constructing network is that each activity must be

unique. Suppose two activities "a" and "b" have to start from the same event and end

at some other but same event then both "a" and "b" can't be given the same number

so one is taken as a dummy activity and is represented by dotted lines.

There are two important types of Float or Slack:

Total Float is the spare time available when all preceding activities occur at the

earliest possible times and all succeeding activities occur at the latest possible times.Total Float = Latest Start - Earliest Start

 Activities with zero Total float are on the Critical Path

Free Float is the spare time available when all preceding activities occur at the

earliest possible times and all succeeding activities occur at the earliest possibletimes.When an activity has zero Total float, Free float will also be zero.

CRITICAL PATH

METHOD (CPM)

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IN CLASS EXERCISE

ACTIVITY DURATION (week) PREDECESSOR

A

B

C

D

E

F

G

H

4

3

2

4

2

3

1

2

-

A

A

B,C

C

D,E

E

F,G