How to Write Requirements
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Telelogic Lifecycle Solutions Get it Right the First Time Telelogic Get it Right the First Time: Writing Better Requirements Part Number: MN-DOR-ED-GTR80-05-01 L License Agreement No part of this publication may be reproduced, transmitted, stored in a retrieval system, nor translated into any human or computer language, in any form or by any means, electronic, mechanical, magnetic, optical, chemical, manual or otherwise, without the prior written permission of the copyright owner, Telelogic AB. Copyright infringement is a serious matter under the United States and foreign Copyright Laws. Telelogic AB reserves the right to revise this publication and to make changes from time to time without obligation to notify authorized users of such changes. Consult Telelogic AB to determine whether any such changes have been made. The terms and conditions governing the licensing of Telelogic software consist solely of those set forth in the written contracts between Telelogic AB and its customers. 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Copyright © 1993 - 2007 Telelogic AB All rights reserved Table of Contents Chapter 1: About this Manual 1 Chapter 1: How to write better requirements 1 Overview . 1 Guidelines to keep in mind . 1 Remember what requirements are for. 2 Requirements are a human issue . 3 Chapter 2: Definition and structure of a requirement 5 A requirement shall be a complete sentence. 5 Shall, will, and must . 5 Anatomy of a good requirement . 6 Chapter 3: Criteria for a good requirement 7 For each requirement ask the question: . 7 Check the requirements as a set . 7 Guidelines for writing good requirements . 8 Chapter 4: Writing user and system requirements 9 Writing the user requirements . 9 What is a user? . 9 System requirements . 9 Writing system requirements . 10 Making requirements testable . 11 Chapter 5: Sources of user requirements 13 Interview users . 13 Working in the environment . 13 Study analogous or existing systems . 14 Examine suggestions and problem reports. 15 Get It Right The First Time: Writing Better Requirements iii Requirements from the help desk and support teams. 15 Improvements made by users. 15 Unintended uses . 15 Workshops. 16 Prototypes . 17 Chapter 6: Organizing requirements 19 You need structure as well as text . 19 Organizing requirements in practice . 20 Defining the scope . 20 Agree on exactly what to include. 20 Identify priorities . 21 Work out what can be afforded. 21 Putting the requirements in the right place . 21 Chapter 7: Requirementsó Aids for Analysis 23 Status information is essential . 23 Analysis made simple . 23 Chapter 8: Reviews 25 The review process . 25 The review meeting. 26 Capturing the suggestions. 26 Make the necessary changes . 27 Golden rules for reviewing: . 27 Chapter 9: Traceability 29 The complexity of large systems . 29 Chapter 10: Controlling change 31 Forces of change . 31 Tracking change . 31 Allow for feedback . 31 iv Get It Right The First Time: Writing Better Requirements Requirements effort throughout the lifecycle. 32 Other helpful hints on managing change . 32 Chapter A: Appendix: Writing pitfalls to avoid 33 Avoid ambiguity . 33 Don't make multiple requirements . 33 Never build in let-out or escape clauses . 34 Don't ramble . ..