© pearson education limited 2004 oht 8.1 cadle and yeates: project management for information...

© Pearson Education Limited 2004

OHT 8.1

Cadle and Yeates: Project Management for Information Systems, 4th edition

Critical Path Method(CPM)


OHT 8.2


Critical Path Method (CPM)

• A project planning and scheduling technique• CPM is part of group of techniques called Network

Models• CPM is broken into:

– Creating Work Breakdown Structure– Creating a Network Diagram of the Project– Computing Activity Times and Activity Total Float– Computing the Project Duration and Critical Path– Creating an Activity Schedule Table– Creating a GANTT Chart Schedule


OHT 8.3


Work breakdown structure (WBS)

InterviewManagingDirector

InterviewFinanceDirector

InterviewStores

Manager

InterviewSales

Manageretc.

Conductinterviews

Investigateother systems

Analyserequirements

Investigatepackages

Investigatehardware

Conductinvestigation

Prepare report

Project

Top level

Second level

Third level

Figures 8.1 - 8.3 Work breakdown structures


OHT 8.4


Product breakdown structure (PBS)

Interviewnotes

Requirementscatalogue

Data flowdiagrams

Packagereports

Analysisproducts

Feasibilityreport

Specialistproducts

Managementproducts

Projectproducts

Top level

Second level

Third level

Figures 8.5 – 8.8 Product breakdown structures


OHT 8.5


Product flow diagram

Interview notes

Draft data flowdiagrams

Draftrequirements

catalogue

Reviewedrequirements

catalogue

Agreed data flowdiagrams

Create requirementscatalogue

Create data flowdiagrams

Add extrarequirements

Review requirementscatalogue

Review data flowdiagrams

Figure 8.9 PRINCE2® product flow diagram


OHT 8.6


Product description

• Purpose

• Composition

• Derivation

• Quality/completion criteria

• Can add:– Format– Related products– Review methods


OHT 8.7


Work packages

Training course

Trainer'smaterials

Exercises Handouts Visual aids

Notes forsession 1

Notes forsession 2

Exercise1A

Exercise1B

Exercise2A

Handout onPlanning

Handout onScheduling

Slides forsession 1

Slides forsession 2

Workpackage 1

Workpackage 2

Figure 8.10 Work packages for a training course


OHT 8.8


Linear responsibility chart

Interview notes

Requirementscatalogue

Use case diagram

Package review

Report text

Report illustrations

Report appendices

Pro

ject

Sp

on

sor

Pro

ject

Ma

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r

An

aly

sis

tea

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ad

er

Ch

ief d

esi

gn

er

De

velo

pm

en

tm

an

ag

er

Test

ma

na

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r

Pro

ject

su

pp

ort

ass

ista

nt

Se

nio

r u

ser

I A R I C

I RA I C

I A R I I C

I A R I I I I

I

I

I

A R

A

I

A

R

R I

I

I

I

Organisation breakdown

Pro

du

ct /

wo

rk p

acka

ge

bre

akd

ow

n

R = Responsible

A = Accountable

C = Consultation

I = Information

OR, could use

I = Initiation

E = Execution

A = Approval

C = Consultation

S = Supervision

Figure 8.11 Linear responsibility chart


OHT 8.9


Establishing Activity Precedence

Code Activity Immediate Predecessors

A Draft Req. Catalogue

B Review Req Catalogue

C Draft data flow diagram

D Interview Notes

E Agreed data flow diagram

Some activities must be down before others


OHT 8.10


Network diagram (activity-on-arrow)

Start

Finish

Conductinterviews

Investigateothersystems

Analyserequirements

Investigatepackages

Investigatehardware

Producereport

Figure 8.12 Network diagram (activity-on-arrow format)


OHT 8.11


Network with durations & critical path

Start

Finish

Conductinterviews

Investigateothersystems

Analyserequirements

Investigatepackages

Investigatehardware

Producereport

8

4

3

8

5

5

Figure 8.13 Network diagram with durations & critical path added

Activities if delayed will delay the whole project (the activities with the longest path)


OHT 8.12


Activity Times

• Activity Earliest Start Time (EST)

• Activity Earliest Finish Time (EFT)

• Activity Latest Start Time (LST)

• Activity Latest Finish Time (LFT)


OHT 8.13


Network diagram (activity-on-node)

Conductinterviews (8)

0 8

0 8

Investigate othersystems (4)

0 4

4 8

Analyserequirements (3)

8 11

13 16

Investigatepackages (8)

8 16

8 16

Investigatehardware (5)

8 13

11 16

Produce report (5)

16 21

16 21

FinishStart

Figure 8.15 Network diagram (activity-on-node format)

ESTEFT

LST LFT

Activity Name

Activity Duration


OHT 8.14


Effort and elapsed time

• Effort = total volume of work

• Elapsed time depends on effort and also:– How many resources are available– What proportion of their time is available to the

project– Delays outside the team’s control (eg lead

times for hardware)– Dependencies on others


OHT 8.15


Activity Total Float

• Is the amount of time that an activity can be delayed without affecting overall project duration

• Formula: Activity Total Float = Activity LST –Activity EST• Activities with total float 0 cannot be delayed without delaying the

whole project• Activities with some total float give some leeway in rescheduling them

without delaying the whole project• However, when we use up the total float on an activity, it may cause

later activities to be delayed and this will reduce their total floats


OHT 8.16


Components of Total Float

• 2 components of Total Float– Free float:

• Part of total float whose usage will not cause subsequent activites to be delayed and thus will not affect total float

– Interfering float:• Part of total float whose usage will cause

subsequent activities to be delayed and thus will affect their total floats


OHT 8.17


Free Float

• The delay activity without affecting the total float of subsequent activities

• Formula:Free Float = min. EST of Activity’s successors – Activity EFT

19 20

G,1

22 23

24 28

J,4

26 30

23 29

G,1

23 29

TF=3 FF=3 Free Float= min(23 and 24) -20


OHT 8.18


Use of Activity Float

• I ffor certain reasons you were force to delay some activities in a project, you would first choose to delay activities with free float. Once you have run out of such activities, you would then delay activities with interfering float.– In delaying such activites you would have to recompute

the total float of all subsequent activities as they may have disappeared

• Choose to delay activities without any total float only as a last resort as doing so would cause the project to be delayed


OHT 8.19


Project Duration and Critical Path

• The shortest possible project duration is equal to the EST of the END activity

• The critical path is the path comprising all activities with zero total float. Delays in any of the activities in the critical path will result in delaying the entire project. We can identify the critical path by looking for all activities with zero total float

• The critical path is also always the longest continuous path activities in a network diagram from the beginning to the end of a project. The duration of the critical path is always equal to the shortest possible project duration

• It is usual to label the critical path by coloring, highlighting it or by drawing two small strokes across all activities in the critical path


OHT 8.20


Timing Convention

• “End of Date”: Day 0 means “End of Day 0”

• “Start of Date”: Day 1 means “Start of Day 1”– If use “Start of Date” for start dates and “End of

Date” for finish dates, and activity starting on Day 1 and ending on Day 2 has a duration of 2 (and not 1) days


OHT 8.21


Activity Scheduling

Activity Duration EST EFT LST LFT Total Float

Free Float

A


OHT 8.22


Network diagram

Conductinterviews (8)

0 8

0 8

Investigate othersystems (4)

0 4

4 8

Analyserequirements (3)

8 11

13 16

Investigatepackages (8)

8 16

8 16

Investigatehardware (5)

8 13

11 16

Produce report (5)

16 21

16 21

FinishStart

Figure 10.1 Dependency network with activity durations


OHT 8.23


Gantt Chart Schedule (Bar chart)

Conduct interviews

Investigate othersystems

Analyse requirements

Investigate packages

Investigate hardware

Produce report

5 10 15 20 25 30 35Days

Activities

Figure 10.3 Schedule for two-person team showing parallel activities

EST

Duration


OHT 8.24


Bar chart with milestones added

Conduct interviews





Produce report

5 10 15 20 25 30 35Days

Activities

Milestone

Figure 10.6 Bar chart showing project milestones


OHT 8.25


Bar chart with ‘overhead’ task added

Conduct interviews





Produce report

5 10 15 20 25 30

35

Days

Activities

Milestone

Project management

Figure 10.7 Bar chart showing project management as continuous activity over project


OHT 8.26


Bar chart and resource histogram

Conduct interviews





Produce report

5 10 15 20 25 30 35Days

Activities

Milestone

3

2

1

Staff

Figure 10.8 Bar chart with resource histogram


OHT 8.27


The project and other plans

One document ortwo?

QUALITY PLAN

How

PROJECT PLAN

Why? What? When?Where? Who?

QUALITY PLAN

How?

RISK MANAGEMENTPLAN

Why not?

One plan orthree?


OHT 8.28


PRINCE2® plans

Project Plan

Stage Plan

Team Plan

Programme Plan

Exception Plan

Figure 10.10 PRINCE2® plans


OHT 8.29


Contents of PRINCE2® project/stage planProduct breakdownstructure

Product flow diagram

Activity network

Financial budget

Resource requirements

Risk assessment

Quality plan

Gantt charts

Product descriptions formajor products

Figure 10.11 Contents of PRINCE2® project and stage plans


OHT 8.30


Project budgetBUDGET FOR: NEW CUSTOMER CONTACT SYSTEM

Expenditure code and heading Monthly figures TotalsMar Apr May Jun Jul Aug Sep

A Direct labour 50 50 70 90 120 70 30 480

B Sub-contract work 30 30 60 60 30 210

C Hardware 100 200 300

D Software 30 60 90

E Telecommunications 10 60 70

F Travel 3 3 1 1 3 2 1 14

G Accommodation and subsistence 2 2 1 1 2 2 1 11

H Project-specific training 10 10

I Support services 2 6 5 13

J Consultancy support 2 2 2 2 6 2 1 17

Contingency (10%) - items B-J only 16 4 3 6 39 4 1 74

Monthly totals: 207 87 104 154 513 112 38 1289

Figure 10.13 Example budget for an IT project

© pearson education limited 2004 oht 8.1 cadle and yeates: project management for information...

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