Practical software estimation: function point methods for insourced and outsourced projects

427 Pages·2007·3.294 MB·English

by  Parthasarathy, M A

Practical Software
Estimation
Infosys Press
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Practical Software
Estimation
Function Point Methods for
Insourced and Outsourced Projects
M. A. Parthasarathy
Foreword by N. R. Narayana Murthy
Chairman and Chief Mentor
Infosys Technologies Ltd.
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This document contains material, which has been extracted from the International Function Point Users Group
(IFPUG) 4.2 Counting Practices Manual. It is reproduced in this document with the permission of IFPUG
(http://www.ifpug.org). The International Function Point Users Group (IFPUG) is a not-for-profit, member
run, user group. The IFPUG mission is to be a recognized leader in promoting and encouraging the effective
management of application software development and maintenance activities using Function Point Analysis
and other software measurement techniques. For more information contact IFPUG at http://www.ifpug.org, or
e-mail [email protected], or phone (USA) 609-799-4900, or fax [phone].
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Library of Congress Cataloging-in-Publication Data
Parthasarathy, M. A.
Practical software estimation : function point methods for insourced and outsourced projects / M. A. Parthasarathy.
p. cm.
Includes bibliographical references and index.
ISBN 0-321-43910-4 (pbk. : alk. paper)
1. Computer software—Development. 2. Computer software—Development—Estimates. I. Title.
QA76.76.D47P356 2007
005.3—dc22
2006036476
Copyright © 2007 M. A. Parthasarathy
All rights reserved. Printed in the United States of America. This publication is protected by copyright, and per-
mission must be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system,
or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For
information regarding permissions, write to Pearson Education, Inc., Rights and Contracts Department, 75
Arlington Street, Suite 300, Boston, MA02116, fax: [phone].
ISBN 0-321-43910-4
Text printed in the United States on recycled paper at Courier in Stoughton, Massachusetts.
First printing, February 2007
To
My son, Aravind, and my wife, Rama,
who kept pushing me to complete this book.
My father, Tiru Narayan, and my mother, Padma,
for grooming me to be worthy of many achievements!
My fellow Infoscions,
for providing me the platform to learn and share.
This page intentionally left blank
CONTENTS
List of Figures .................................................................... xvii
List of Tables ...................................................................... xix
Foreword............................................................................... xxv
Preface .................................................................................. xxvii
Acknowledgments ............................................................. xxxiii
Chapter 1: Introduction ....................................................................... 1
What Is Software Estimation? .................................................. 1
Ingredients of a Good Estimation ............................................ 6
Activity Scope .......................................................................... 6
Work Environment .................................................................. 6
Consistency ............................................................................. 7
Usage of Tools........................................................................... 7
Learning from Past Experience ................................................ 8
Software Project Estimation ..................................................... 8
Project Scope ............................................................................ 9
Software Environment ............................................................. 10
Team Experience ....................................................................... 11
Software Development Tools .................................................... 11
Continuous Improvement Cycle ............................................. 12
Why Software Estimation? ....................................................... 15
Metrics—Past, Present, and Future ........................................ 16
Importance of Estimation ......................................................... 18
Estimation—Who and How ..................................................... 19
vii
viii Contents
Conclusion .................................................................................. 21
References ................................................................................... 22
Other Interesting Reading Material ........................................ 23
Chapter 2: Role of Estimation in Software Projects ....................... 25
Software Projects and Estimation ............................................ 25
Project Budget Approval Phase ................................................ 26
Project Contract Phase ............................................................. 27
Project Execution Phase ........................................................... 28
Estimation and Measurement .................................................. 31
Estimation and Measurement Complexities............................. 32
Modularized Estimation .......................................................... 34
Case Study—Modularized Estimation .................................... 37
Large Application Systems ....................................................... 40
Heterogeneous Portfolio of Application Systems ..................... 41
Conclusion .................................................................................. 42
References ................................................................................... 43
Other Interesting Reading Material ........................................ 43
Chapter 3: AStudy of Function Point Analysis .............................. 45
Why Estimation? ........................................................................ 45
What Is an Estimation Method? .............................................. 46
Function Points .......................................................................... 47
What Is a Function Point? ....................................................... 47
Function Point as a Measuring Yardstick ............................... 49
Uses and Benefits of Function Points ...................................... 50
Function Point Analysis ............................................................ 51
FPA—Objectives...................................................................... 53
The FPAModel......................................................................... 55
The FPAProcess ....................................................................... 57
Conclusion .................................................................................. 70
References ................................................................................... 72
Contents ix
Chapter 4: Data Functions ................................................................... 73
Introduction ................................................................................ 73
Definition of Files ...................................................................... 74
AData File Example.....................................................................74
Data Functions Defined by IFPUG .......................................... 75
ILFs and EIFs ........................................................................... 76
Embedded Terms ...................................................................... 77
Rules for Identification of ILFs and EIFs ................................. 80
Determining Complexity of ILFs and EIFs .............................. 81
Complexity and FP Count Contributions ................................ 86
Tips to Remember ..................................................................... 88
Conclusion .................................................................................. 95
Identifying ILF/EIF: User View versus Developer View ......... 95
References ................................................................................... 96
Other Interesting Reading Material ........................................ 96
Chapter 5: Transactional Functions ................................................... 97
Introduction ................................................................................ 97
Definition of Transactions ......................................................... 98
Albrecht’s Definition of Transactions ..................................... 100
Ingredients of a Transaction ..................................................... 100
Transactional Functions Defined by IFPUG ........................... 102
EI, EO, and EQ ........................................................................... 104
External Input .......................................................................... 104
External Output ...................................................................... 104
External Inquiry ...................................................................... 104
Embedded Terms ...................................................................... 105
Rules for Identification of EI, EO, and EQ .............................. 107
Complexity and FPCount Contributions ............................. 111
External Inputs ........................................................................ 111
External Outputs/External Inquiries ...................................... 112
Step-by-Step FP Contribution Calculation Process ................. 112
CRUD Transactions ................................................................. 115