CONTENIDO
Preface xv
PART I SOFTWARE REQUIREMENTS: WHAT, WHY, AND WHO
1 The Essential Software Requirement 3
Software Requirements Defined 7
Some Interpretations of Requirement 7
Levels of Requirements 8
What Requirements Are Not 12
Requirements Development and Management 12
Requirements Development 13
Requirements Management 14
Every Project Has Requirements 15
When Bad Requirements Happen to Nice People 17
Insufficient User Involvement 18
Creeping User Requirements 18
Ambiguous Requirements 18
Gold Plating 19
Minimal Specification 19
Overlooked User Classes 20
Inaccurate Planning 20
Benefits from a High-Quality Requirements Process 20
Characteristics of Excellent Requirements 22
Requirement Statement Characteristics 22
Requirements Specification Characteristics 24
2 Requirements from the Customer´s Perspective 27
Who Is the Customer? 29
The Customer-Development Partnership 31
Requirements Bill of Rights for Software Customers 33
Requirements Bill of Responsibilities for Software Customers 36
What About Sign-Off? 39
3 Good Practices for Requirements Engineering 43
Knowledge 45
Requirements Elicitation 47
Requirements Analysis 50
Requirements Specification 52
Requirements Validation 53
Requirements Management 54
Project Management 56
Getting Started with New Practices 57
A Requirements Development Process 59
4 The Requirements Analyst 63
The Requirements Analyst Role 63
The Analyst s Tasks 65
Essential Analyst Skills 68
Essential Analyst Knowledge 70
The Making of an Analyst 71
The Former User 71
The Former Developer 72
The Subject Matter Expert 73
Creating a Collaborative Environment 73
PART II SOFTWARE REQUIREMENTS DEVELOPMENT
5 Establishing the Product Vision and Project Scope 77
Defining the Vision Through Business Requirements 78
Conflicting Business Requirements 80
Business Requirements and Use Cases 81
Vision and Scope Document 81
1. Business Requirements 83
2. Vision of the Solution 85
3. Scope and Limitations 86
4. Business Context 88
The Context Diagram 90
Keeping the Scope in Focus 91
6 Finding the Voice of the Customer 95
Sources of Requirements 96
User Classes 97
Finding User Representatives 101
The Product Champion 103
External Product Champions 104
Product Champion Expectations 105
Multiple Product Champions 106
Selling the Product Champion Idea 107
Product Champion Traps to Avoid 108
Who Makes the Decisions? 109
7 Hearing the Voice of the Customer 113
Requirements Elicitation 115
Elicitation Workshops 117
Classifying Customer Input 119
Some Cautions About Elicitation 125
Finding Missing Requirements 126
How Do You Know When You´re Done? 129
8 Understanding User Requirements 131
The Use-Case Approach 133
Use Cases and Usage Scenarios 134
Identifying Use Cases 138
Documenting Use Cases 139
Use Cases and Functional Requirements 145
Benefits of Use Cases 147
Use-Case Traps to Avoid 148
Event-Response Tables 149
9 Playing by the Rules 153
The Rules of the Business 154
Facts 155
Constraints 156
Action Enablers 157
Inferences 158
Computations 158
Documenting Business Rules 160
Business Rules and Requirements 161
10 Documenting the Requirements 165
The Software Requirements Specification 166
Labeling Requirements 168
Dealing with Incompleteness 169
User Interfaces and the SRS 170
A Software Requirements Specification Template 171
1. Introduction 172
2. Overall Description 173
3. System Features 175
4. External Interface Requirements 176
5. Other Nonfunctional Requirements 178
6. Other Requirements 180
Guidelines for Writing Requirements 181
Sample Requirements, Before and After 185
The Data Dictionary 190
11 A Picture Is Worth 1024 Words 193
Modeling the Requirements 194
From Voice of the Customer to Analysis Models 195
Data Flow Diagram 197
Entity-Relationship Diagram 200
State-Transition Diagram 203
Dialog Map 206
Class Diagrams 210
Decision Tables and Decision Trees 212
A Final Reminder 214
12 Beyond Functionality: Software Quality Attributes 215
Quality Attributes 216
Defining Quality Attributes 218
Attributes Important to Users 219
Attributes Important to Developers 225
Performance Requirements 227
Defining Nonfunctional Requirements By Using Planguage 228
Attribute Trade-Offs 229
Implementing Nonfunctional Requirements 231
13 Risk Reduction Through Prototyping 233
Prototyping: What and Why 234
Horizontal Prototypes 235
Vertical Prototypes 236
Throwaway Prototypes 236
Evolutionary Prototypes 238
Paper and Electronic Prototypes 240
Prototype Evaluation 242
The Risks of Prototyping 243
Prototyping Success Factors 245
14 Setting Requirement Priorities 247
Why Prioritize Requirements? 248
Games People Play with Priorities 249
A Prioritization Scale 250
Prioritization Based on Value, Cost, and Risk 252
15 Validating the Requirements 259
Reviewing Requirements 262
The Inspection Process 264
Requirements Review Challenges 272
Testing the Requirements 273
Defining Acceptance Criteria 280
16 Special Requirements Development Challenges 283
Requirements for Maintenance Projects 283
Begin Capturing Information 284
Practice New Requirements Techniques 287
Follow the Traceability Chain 287
Update the Documentation 288
Requirements for Package Solutions 288
Develop Use Cases 289
Consider Business Rules 290
Define Quality Requirements 290
Requirements for Outsourced Projects 291
Requirements for Emergent Projects 293
Casual User Requirements Specification 294
On-Site Customer 295
Early and Frequent Prioritization 296
Simple Change Management 296
17 Beyond Requirements Development 297
From Requirements to Project Plans 298
Requirements and Estimation 300
Requirements and Scheduling 303
From Requirements to Designs and Code 304
From Requirements to Tests 307
From Requirements to Success 309
PART III SOFTWARE REQUIREMENTS MANAGEMENT
18 Requirements Management Principles and Practices 313
The Requirements Baseline 315
Requirements Management Procedures 315
Requirements Version Control 317
Requirement Attributes 319
Tracking Requirements Status 321
Measuring Requirements Management Effort 324
19 Change Happens 327
Managing Scope Creep 329
The Change-Control Process 331
Change-Control Policy 332
Change-Control Process Description 333
The Change Control Board 338
CCB Composition 339
CCB Charter 339
Change-Control Tools 341
Measuring Change Activity 342
Change Isn´t Free: Impact Analysis 344
Impact Analysis Procedure 345
Impact Analysis Report Template 350
20 Links in the Requirements Chain 353
Tracing Requirements 354
Motivations for Tracing Requirements 357
The Requirements Traceability Matrix 358
Tools for Requirements Tracing 362
Requirements Traceability Procedure 364
Is Requirements Traceability Feasible? Is It Necessary? 365
21 Tools for Requirements Management 367
Benefits of Using a Requirements Management Tool 370
Requirements Management Tool Capabilities 372
Implementing Requirements Management Automation 374
Selecting a Tool 374
Changing the Culture 375
Making Requirements Management Tools Work for You 378
PART IV IMPLEMENTING REQUIREMENTS ENGINEERING
22 Improving Your Requirements Processes 381
How Requirements Relate to Other Project Processes 382
Requirements and Various Stakeholder Groups 384
Fundamentals of Software Process Improvement 386
The Process Improvement Cycle 389
Assess Current Practices 389
Plan Improvement Actions 390
Create, Pilot, and Implement New Processes 392
Evaluate Results 393
Requirements Engineering Process Assets 395
Requirements Development Process Assets 396
Requirements Management Process Assets 398
Requirements Process Improvement Road Map 399
23 Software Requirements and Risk Management 401
Fundamentals of Software Risk Management 403
Elements of Risk Management 403
Documenting Project Risks 404
Planning for Risk Management 407
Requirements-Related Risks 408
Requirements Elicitation 408
Requirements Analysis 410
Requirements Specification 410
Requirements Validation 411
Requirements Management 411
Risk Management Is Your Friend 412
Epilogue 415
A Current Requirements Practice Self-Assessment 417
B Requirements and Process Improvement Models 425
The Capability Maturity Model for Software 425
CMMI-SE/SW 428
Requirements Management Process Area 430
Requirements Development Process Area 430
C Requirements Troubleshooting Guide 433
Root Cause Analysis 434
Common Symptoms of Requirements Problems 435
Common Barriers to Implementing Solutions 436
D Sample Requirements Documents 457
Vision and Scope Document 458
Use Cases 463
Software Requirements Specification 469
Business Rules 482
GLOSSARY 483
REFERENCES 491