Discovering Requirements

"This book is not only of practical value. It's also a lot of fun
to read." Michael Jackson, The Open University.

Do you need to know how to create good requirements?

Discovering Requirements offers a set of simple, robust, and
effective cognitive tools for building requirements. Using worked
examples throughout the text, it shows you how to develop an
understanding of any problem, leading to questions such as:

• What are you trying to achieve?

• Who is involved, and how?

• What do those people want? Do they agree?

• How do you envisage this working?

• What could go wrong?

• Why are you making these decisions? What are you assuming?

The established author team of Ian Alexander and Ljerka Beus-Dukic
answer these and related questions, using a set of complementary
techniques, including stakeholder analysis, goal modelling, context
modelling, storytelling and scenario modelling, identifying risks
and threats, describing rationales, defining terms in a project
dictionary, and prioritizing.

This easy to read guide is full of carefully-checked tips and
tricks. Illustrated with worked examples, checklists, summaries,
keywords and exercises, this book will encourage you to move closer
to the real problems you're trying to solve. Guest boxes from other
experts give you additional hints for your projects.

Invaluable for anyone specifying requirements including IT
practitioners, engineers, developers, business analysts, test
engineers, configuration managers, quality engineers and project
managers.

A practical sourcebook for lecturers as well as students studying
software engineering who want to learn about requirements work in
industry.

Once you've read this book you will be ready to create good
requirements!

Zusammenfassung
"This book is not only of practical value. It's also a lot of fun to read." Michael Jackson, The Open University.

Do you need to know how to create good requirements?

Discovering Requirements offers a set of simple, robust, and effective cognitive tools for building requirements. Using worked examples throughout the text, it shows you how to develop an understanding of any problem, leading to questions such as:

• What are you trying to achieve?
• Who is involved, and how?
• What do those people want? Do they agree?
• How do you envisage this working?
• What could go wrong?

• Why are you making these decisions? What are you assuming?

  The established author team of Ian Alexander and Ljerka Beus-Dukic answer these and related questions, using a set of complementary techniques, including stakeholder analysis, goal modelling, context modelling, storytelling and scenario modelling, identifying risks and threats, describing rationales, defining terms in a project dictionary, and prioritizing.

This easy to read guide is full of carefully-checked tips and tricks. Illustrated with worked examples, checklists, summaries, keywords and exercises, this book will encourage you to move closer to the real problems you're trying to solve. Guest boxes from other experts give you additional hints for your projects.

Invaluable for anyone specifying requirements including IT practitioners, engineers, developers, business analysts, test engineers, configuration managers, quality engineers and project managers.
A practical sourcebook for lecturers as well as students studying software engineering who want to learn about requirements work in industry.

Once you've read this book you will be ready to create good requirements!

Inhalt

Acknowledgements xv

Foreword xvii

Part I: Discovering Requirement Elements 1

1 Introduction 3

1.1 Summary 4

1.2 Why You Should Read This Book 4

1.3 Simple but Not Easy 6

1.4 Discovered, Not Found 7

1.4.1 Many Different Situations 9

1.5 A Softer Process, at First 12

1.6 More than a List of 'The System Shalls' 16

1.6.1 A Network of Requirement Elements 16

1.6.2 Discovery as Search 18

1.7 A Minimum of Process: The Discovery Cycle 18

1.8 The Structure of this Book 20

1.8.1 Part I: Discovering Requirement Elements 21

1.8.2 Part II: Contexts for Discovery 22

1.9 Further Reading 22

1.9.1 Books on 'Softer' Approaches 22

1.9.2 Books on the Philosophical Background 23

1.9.3 Books on 'Harder' Approaches 24

2 Stakeholders 27

2.1 Summary 28

2.2 Discovering Stakeholders 28

2.2.1 Operational Stakeholders within 'The System' 30

2.2.2 Stakeholders in the Containing System and Wider Environment 30

2.3 Identifying Stakeholders 37

2.3.1 From your Sponsor or Client 37

2.3.2 With a Template such as the Onion Model 37

2.3.3 By Comparison with Similar Projects 40

2.3.4 By Analysing Context 40

2.4 Managing Your Stakeholders 41

2.4.1 Engaging with Stakeholders 41

2.4.2 Keeping Track of Stakeholders 42

2.4.3 Analysing Influences 42

2.4.4 Prioritising Stakeholders 43

2.4.5 Involving Stakeholders 45

2.4.6 The Integrated Project Team 45

2.5 Validating Your List of Stakeholders 45

2.5.1 Things To Check the Stakeholder Analysis Against 46

2.6 The Bare Minimum of Stakeholder Analysis 46

2.7 Next Steps: Requirements from Stakeholders 46

2.8 Exercise 49

2.9 Further Reading 49

3 Goals 51

3.1 Summary 52

3.2 Discovering Goals 52

3.2.1 Worked Example: Goals for a Spacecraft 54

3.2.2 Worked Example: Goals for a Restaurant 57

3.2.3 Worked Example: Tram Goals and Trade-offs 59

3.2.4 Finding Solutions to Goal Conflicts 62

3.2.5 Contexts for Discovering Goals 63

3.2.6 The Negative Side 65

3.3 Documenting Goals 68

3.3.1 Drawing Goal Diagrams 69

3.3.2 Other Ways of Documenting Goals 69

3.4 Validating Goals 71

3.4.1 Things To Check Goals Against 73

3.5 The Bare Minimum of Goals 73

3.6 Next Steps 73

3.7 Exercises 73

3.8 Further Reading 74

3.8.1 Goals 74

3.8.2 The Negative Side 74

3.8.3 The i Goal Modelling Notation 74

4 Context, Interfaces, Scope 75

4.1 Summary 76

4.2 Introduction 76

4.3 A 'Soft Systems' Approach for Ill-Defined Boundaries 77

4.3.1 You are Part of the Soft System you are Observing 78

4.3.2 From Stakeholders to Boundaries 79

4.3.3 Identifying Interfaces 83

4.3.4 Documenting Interfaces 84

4.3.5 Validating your Choice of Boundary 86

4.4 Switching to a 'Hard Systems' Approach for Known Events 87

4.4.1 The Traditional Context Diagram 87

4.4.2 Scope as a List of Events 87

4.4.3 Expressing Event-handling Functions 89

4.4.4 Strengths and Weaknesses of Context Diagrams 92

4.4.5 Validating Interfaces and Events 93

4.4.6 Things To Check Context and Interfaces Against 95

4.5 The Bare Minimum of Context 95

4.6 Next Steps 95

4.7 Exercise 95

4.8 Further Reading 96

4.8.1 Soft Approaches 96

4.8.2 Event-Driven Approaches 96

4.8.3 Writing Requirements 96

5 Scenarios 97

5.1 Summary 98

5.2 Discovering Scenarios 98 5...