SPM Chapter6

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Activity planning

CHAPTER

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Activity planning

CHAPTER

Objectives

• Produce an activity plan for a project;

• Estimate the overall duration of a project;

• Create a critical path and a precedence

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Activity planning

6.1 Introduction

A detailed plan for the project, however, must also include a schedule

indicating the start and completion time for each activity. This will enable us to:

• Ensure that the appropriate resources will be available precisely when required;

• Avoid different activities competing for the same resources at the same time;

• Produce a detailed schedule showing which staff carry out each activity;

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Software Project Management

activity;

• Produce a detailed plan against which actual achievement may be measured;

• Produce a time cash flow forecast;

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Activity planning

6.1 Introduction

To be effective:

• A plan must be stated as a set of targets.

• The activity plan does this by providing a target start and completed date for each activity.

• The start and completions of activities must be clearly visible and this is one of the reason why it is advisable to ensure that each and every project activity produces some tangible product.

• Monitoring the project’s progress to ensure that the products of each activity are delivered on time.

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Activity planning

6.2 The objectives of activity planning

Feasibility assessment

Resource allocation

Detailed costing

Motivation

Co-ordination

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Activity planning

6.3 When to plan

– Planning is an ongoing process of refinement, each iteration

becoming more detailed and more accurate than the last. Over becoming more detailed and more accurate than the last. Over successive iterations, the emphasis and purpose of planning will shift.

– The main purpose of planning will be to estimate timescales and

the risks of not achieving target completion dates or keeping within budget.

– Throughout the project, until the final deliverable has reached the

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Activity planning

6.4 Project schedules

Select Project

0

Identify project

1 Identify project 2 Identify project

scope and objective

1 Identify project

infrastructure

2

Identify the products and activities

4 Estimate effort for activity 5 Identify activity risks 6 Analyze project characteristics 3

For each activity Lower level detail

Review

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Allocate resources

7

Review/publicize plan

8

Lower level planning

10

Execute plan

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Activity planning

6.4 Project schedules

Creating a project schedule comprises four main stages:

Ideal activity plan

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Activity planning

6.5 Projects and activities

Defining activities

• A project is composed of a number of interrelated activities;

• A project may start when at least one of its activities is ready to

start;

• A project will be completed when all of the activities it

encompasses have been completed;

• An activity must have a clearly defined start and a clearly defined

end-point, normally marked by the production of a tangible deliverable;

• If an activity requires a resource then that resource requirement

must be forecastable and is assumed to be required at a constant

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must be forecastable and is assumed to be required at a constant level throughout the duration of the activity.

• The duration of an activity must be forecastable – assuming

normal circumstances, and the reasonable availability of resources;

• Some activities might require that others are completed before

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Activity planning

6.5 Projects and activities

Identifying activities

The activity-based approach

– Consists of creating a list of all the activities that the project is

thought to involve.

– Ad hoc manner

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Activity planning

6.5 Projects and activities

Introduction to the WBS

A Work Breakdown Structure is a results-oriented family tree that captures all the work of a project in an organized way. It is often portrayed graphically as a hierarchical tree, a project in an organized way. It is often portrayed graphically as a hierarchical tree, however, it can also be a tabular list of "element" categories and tasks or the indented task list that appears in your Gantt chart schedule. As a very simple example, Figure 1 shows a WBS for a hypothetical banquet.

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Activity planning

6.5 Projects and activities

The product-based approach

– Consists of producing a Product

Breakdown Structure and a Product Flow Diagram.

– PFD can therefore be easily

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Activity planning

6.5 Projects and activities

The hybrid approach

– WBS may be based upon the project’s products as follows,

which is in turn based on a simple list of final deliverables and,

– For each deliverable, a set of activities required to produce

that product.

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Activity planning

6.5 Projects and activities

A framework dictating the number of levels and the nature of each level in the structure may be imposed on a WBS. For example, in their MITP methodology, structure may be imposed on a WBS. For example, in their MITP methodology, IBM recommend that the following five levels should be used in a WBS:

Level 1 : Project.

Level 2 : Deliverable such as software, manuals, training course.

Level 3 : Components which are the key work items needed to produce deliverables, such as the modules and tests required to produce the system software.

produce the system software.

Level 4 : Work-packages which are major work items, or collection of related tasks, required to produce a component.

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Activity planning

6.6 Sequencing and scheduling activities

On large project, it is better to separate out these activities:

–

To sequence the task

–

To sequence the task

according to their

logical relationship

–

To schedule them

taking into account

resources and other

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Activity planning

6.7 Network planning models

CPM (Critical Path Method) and PERT (Program Evaluation Review Technique)

Evaluation Review Technique)

Activity-on-arrow, Activity-on-node

NODE (Circle) representing the events of activities

starting and finishing.

Activity-on-node is activity represented as node

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Activity planning

6.8 Formulating a network model

Specify

Module A _{Module A}Design _{Module A}Cost/test

Specify Overall system Module A Specify Module B Specify Module C Specify Check Specifications Module A Design Module B Design Module C Module A Cost/test Module B Cost/test Module C Integrate/test system Slide# 17

Specify

Module D _{Module D}Design _{Module D}Cost/test

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Activity planning

6.8 Formulating a network model

5

Design Module A

Code/test Module A

1 2 3 4 9 10

6

7

Specify overall System

Specify module A Specify module B

Specify module C Specify module D

Design Module B Design Module C Design Code/test Module B Code/test Module C Code/test Integrate/ Test system 8 Design Module D Code/test Module D

Project activity network fragment represented as a CPM network

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Activity planning

Activity-on-Node

Constructing precedence networks

A project network should have only one start node A project network should have only one end node A project network should have only one end node A node has duration (Fig 6.7)

Links normally have no duration (Fig 6.9)

Precedents are the immediate preceding activities Time moves from left to right

A network may not contain loops (Fig 6.10)

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A network may not contain loops (Fig 6.10)

A network should not contain dangles (Fig 6.11, 6.12) Representing lagged activities (Fig 6.13)

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Activity planning

6.8 Formulating a network model

Code

Program

test Install

Data Take-on

test Install

Fragment of a precedence network

Code program

Test program

Release program

Correct errors

Diagnose errors

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Activity planning

6.8 Formulating a network model

Design program Code program Test program Install program Write user

manual A dangle

Design program Code program Test program Install program Sign-off Write user manual

Resolving the dangle

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manual

Resolving the dangle

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Activity planning

6.8 Formulating a network model

Labeling conventions

Activity description

Activity label Duration Earliest

start

Earliest finish Latest

start

Latest finish

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Activity planning

6.9 Adding the time dimension

Example of project specification

Activity _Duration

(Week)

Precedents (Week)

A Hardware selection 6

-B Software design 4

-C Install hardware 3 A

D Code & Test software 4 B

E File take-on 3 B

F Write user manual 10

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-G User Training 3 E, F

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Activity planning

6.10 The forward pass

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Activity planning

6.9 Adding the time dimension

The critical path approach is concerned with two primary objectives: • Planning the project in such a way that it is completed as quickly • Planning the project in such a way that it is completed as quickly

as possible.

• Identifying those activities where a delay in their execution is likely to affect the overall end date of the project or later

activities’ start dates.

- Forward pass

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Activity planning

6.10 The forward pass

– to calculate the earliest dates on which each activity may be

started and completed. started and completed.

– Where an actual start is known, the calculations may be

carried out using actual dates.

– Alternatively we can use day or week numbers and that is the

approach we shall adopt here.

– Date indicate the end of the project and the project is

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Activity planning

6.10 The forward pass

A 6 wks

Hardware design

C 3 wks

Build hardware

0 6 6 9

Start Software Finish

design

B 4 wks

F 10 wks

Code Software

D 4 wks

E 3 wks

Install And test

H 2 wks

G 3 wks

0 4 4 8 9 11

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User Manual

F 10 wks

File Take-on

E 3 wks

User Training

G 3 wks

Precedence network for the example project

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Activity planning

6.11 The backward pass

– To calculate the latest date at which each activity may be started

and finished without delaying the end date of the project.

– In calculating the latest dates, we assume that the latest finish

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Activity planning

6.11 The backward pass

A 6 wks

C 3 wks

0 6 6 9

11

8

2

design

B 4 wks

F 10 wks

D 4 wks

E 3 wks

H 2 wks

G 3 wks

0 4 4 8 9 11

13 11 11 7 7 3 Slide# 29

User Manual

F 10 wks

E 3 wks

G 3 wks

0 10 4 7 10 13

13

10

10 7

0

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Activity planning

6.12 Identifying the critical path

• There will be at least one path through the network that defines

the duration of the project known as the critical path.

• The difference between an activity’s earliest start date and its

latest start date is known as the activity’s float - it is measure of how much the start or completion of an activity may be delayed without affecting the end date of the project.

• The significance of critical path is twofold:

– In managing the project, we must pay attention to monitoring activities on the critical path.

monitoring activities on the critical path.

– In planning the project, it is the critical path that we must shorten if we are to reduce the overall duration of the

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Activity planning

6.12 Identifying the critical path

A 6 wks

C 3 wks

0 6 6 9

11

8

2

2 wks 2 wks

8 weeks 5 weeks

design

B 4 wks

F 10 wks

D 4 wks

E 3 wks

H 2 wks

G 3 wks

0 4 4 8 9 11

13 11 11 7 7 3 2 wks

3 wks 3 wks 2 wks

2 wks

8 weeks

7 weeks

5 weeks

7 weeks 4 weeks

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User Manual

F 10 wks

E 3 wks

G 3 wks

0 10 4 7 10 13

13

10

10 7

0

0 wks 3 wks 0 wks

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Activity planning

6.13 Activity float

The number of other measures of activity float, including:

• Free float: the time by which an activity may be delayed without affecting any subsequent activity.

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Activity planning

6.14 Shortening the project duration

- We would normally consider attempting to reduce activity

durations. durations.

- Applying more resources to the task – working overtime or

procuring additional staff, etc.

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Activity planning

6.15 Identifying critical activities

- Identify ‘near-critical’ paths;

- Identify critical activities is an important step in risk analysis,

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Activity planning

6.16 Activity-on-arrow networks

Activity-on-arrow network activities are represented by links (or arrows) and the nodes represent events of activities (or links (or arrows) and the nodes represent events of activities (or groups of activities) starting or finishing.

A B

C

D H

1

2

3 ₄ 6

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B

F E

D H

G

1 3 4

5

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Activity planning

6.16 Activity-on-arrow networks

Activity-on-arrow network rules and conventions

• A project network may have only one start node;

• A project network may have only one end node;

• A link has duration;

• Nodes have no duration;

• Time moves from left to right; _numberEvent

• Nodes are numbered sequentially;

• A network may not contain loops;

• A network may not contain dangles;

Latest date Earliest

date

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Activity planning

6.16 Activity-on-arrow networks

Activity Duration

(Week)

Precedents

A Hardware selection 6

-B Software design 4

-2

C Install hardware 3 A

D Code & Test software 4 B

E File take-on 3 B

-G User Training 3 E, F

H Install & Test System 2 C, D

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A B

F E C

D H

G

1 3 4

5

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Activity planning

6.16 Activity-on-arrow networks

Activity Duration Earliest Latest Earliest Latest Total (week) st.date st.date fin.date fin.date float

A 6 0 6

B 4 0 4

C 3 6 9

2 8 3 7 8 11 2 3 2

C 3 6 9

D 4 4 8

E 3 4 7

F 10 0 10

G 3 10 13

H 2 9 11

A C

2

6

= 6 = 3

8 11 7 11 7 10 0 10 10 13 11 13 8 2 3 3 0 0 2 2 A B F E D H G

1 3 4

5

6

0 4 9

10

13

= 6

= 4 = 4

= 3

= 10

= 2

= 3

0 7 11

10

13

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Activity planning

4

Exercise

A = 8 B = 11

C = 7

D = 6

E = 10

G = 5

H = 4 F = 6

1 2 3

4

5

6

7

0 ₀ 0 8 19

Dummy

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Critical Path =

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Activity planning

4

Exercise

A = 8 B = 11

C = 7

D = 6

E = 10

G = 5

H = 4 F = 6

1 2 3

4

5

6

7

0 ₀ 0 8 19

Dummy 26 25 30 34 34 34 0 30 25 28 19 8 0 0 22 0 0

Critical Path =

Path =

34

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Activity planning

6.17 Conclusion

This chapter we have discussed the use of the critical path method and precedence networks to obtain an ideal activity plan. This plan tells us the precedence networks to obtain an ideal activity plan. This plan tells us the order in which we should execute activities and the earliest and latest we can start and finish them.

These techniques help us to identify which activities are critical to meeting a target completion date.

In order to manage the project we need to turn the activity plan into a schedule that will specify precisely when each activity is scheduled to start and finish. Before we can do this, we must consider what resources will be required

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