Functional Software Size Measurement Methodology with Effort Estimation and Performance Indication

Jasveer Singh

• Publisher: Wiley-IEEE Computer Society Pr
• Year: 2017
• Print ISBN: 9781119238058
• eBook ISBN: 9781119238119
• Edition: 1
• Topic: Computer Science
• Subtopic: Project Management
• Index: Computer Science

Presents a new, effective methodology in software size measurement

Software size measurement is an extremely important and highly specialized aspect of the software life cycle. It is used for determining the effort and cost estimations for project planning purposes of a software project's execution, and/or for other costing, charging, and productivity analysis purposes. Many software projects exceed their allocated budget limits because the methodologies currently available lack accuracy.

The new software size measurement methodology presented in this book offers a complete procedure that overcomes the deficiencies of the current methodologies, allowing businesses to estimate the size and required effort correctly for all their software projects developed in high level languages. The Functional Software Size Measurement Methodology with Effort Estimation and Performance Indication (FSSM) allows for projects to be completed within the defined budget limits by obtaining accurate estimations. The methodology provides comprehensive and precise measurements of the complete software whereby factual software size determination, development effort estimation, and performance indications are obtained. The approach is elaborate, effective and accurate for software size measurement and development effort estimation, avoiding inaccurate project planning of software projects.

Key features:

• Pinpoints one of the major, originating root causes of erroneous planning by disclosing hidden errors made in software size measurement, and consequently in effort estimates and project planning
• All the major relevant and important aspects of software size measurement are taken into consideration and clearly presented to the reader

Functional Software Size Measurement Methodology with Effort Estimation and Performance Indication is a vital reference for software professionals and Master level students in software engineering.

For further information and materials relating to this book, such as FSSM 1.0 Calculations Template for Results Tables and Graphs, containing Calculations, and Results Tables/Graphs for the Mini FSSM Example, please visit the following two accompanying websites:

http://booksupport.wiley.com

www.fssm.software

Part One
FSSM: Introduction

Chapter 1
Introduction to Functional Software Size Measurement

1.1 Introduction

For software projects, it is very important to determine the size of the software for development effort estimation, project planning, and cost/productivity analysis.

How much effort will be spent on the software development – analysis, design, coding, testing, and documentation – for a particular application depends on the size of the software to be developed.

The size of the software to be developed depends on the functionality required by the application, and the effort is spent to develop all the required functionality.

The functionality required by the application is described in the Functional User Requirements (FUR)^[1] which are the specifications of the required functionality and hence are also known as the Functional Requirements Specifications (FRS). These terms – FUR (Functional User Requirements)^[1] and FRS (Functional Requirements Specifications) – denote the same thing, that is, the specifications of the user functionality required by the application.

1.2 Functional Size Measurement and Effort Estimation

Functional Size Measurement (FSM)^[1] is an effective method for measuring the size of the software because it is meant to measure the functionality which is described in the FRS and on which the effort is spent for analysis, design, coding, testing, documentation, and maintenance.

All the functionality of the application is distributed in different constituent components of the software. These components are defined as Base Functional Components (BFCs)^[1] in the ISO/IEC 14143-1^[1] standards. Measurement of the size of software is achieved by measuring the size of the BFCs^[1] and computing the total size based on the sizes of the BFCs^[1].

The constituent components, that is, the BFCs^[1], of the software comprise sub-types of the BFCs^[1], defined as the Base Functional Component Types (BFC Types)^[1] in the ISO/IEC 14143-1^[1] standards. Measurement of the size of the BFCs^[1] is achieved by measuring the size of the BFC Types^[1] and computing the size of the BFCs^[1] from the sizes of the BFC Types^[1].

After deciding the boundaries which define the limits of the software measurement to a particular area of functionality specified in the FUR^[1], the functional size of the BFC Types^[1] is calculated by assigning the Units of Functional Size^[2] to the BFC Types^[1]. The functional size unit is defined in the methodologies mostly as Function Point^[4]. Function Points^[4] are thus assigned to various BFC Types^[1] and are summed up for the entire functionality within the defined boundaries to produce the total software size of the corresponding BFCs^[1], and then the sum of the Function Points^[4] of the BFCs^[1] produces the total software size.

Because of some substantial limitations (details of which are described in this and later chapters), in some of the popular and widely used software size measurement methodologies available, various multiplication factors which are different according to the type/field and functional contents of applications are used subsequently in order to estimate the effort required for development. The use of multiplication factors is required because a very limited part of all the measurable BFC Types^[1] of a part of all the measurable BFCs^[1] is measured, and from that small partial measurement, an attempt is made to estimate the effort of development for the whole software based on the assumption that the multiplication factors will take care of the unmeasured part and will thus produce the correct effort estimation. This approach may give erroneous results as clarified in further description. The FSSM is specially designed to overcome such limitations.

1.3 Important Considerations for the Software Size Measurement and Effort Estimation

Care should be taken while selecting a methodology to use for the Functional Size Measurement^[1]. The methodology should be such that it measures all the major, relevant functionality on which the effort is required to be spent on development; otherwise – in case of measurement of only a small part of the software functionality – the significance of measurement is lost. The methodology should be simple and easy to use as well. Hence, there is a need of an integral software size measurement methodology which is presented in this book.

The following are some important facts that should be considered regarding the Functional Size Measurement^[1], and methodologies to measure the functional size:

1. Software is composed of several distinct components which are inter-related but do not have any obligatory fixed size proportion relationship with respect to one another in any software application. That means, if there are four components: c1, c2, c3 and c4, their size may have any proportion according to the functional requirements concerning these components in different applications. So the magnitude of c1 may be much greater (measured by any method, e.g., counts, units) than c2 in one software application but it may be the opposite in another application. Similarly, the size proportion of c1 to other components in one application may be entirely different than in another application.
2. Each component has several features. For example, component c1 may have two features: c1f1, c1f2; component c2 may have three features: c2...

Table of contents

• Cover
• Title Page
• Copyright
• Preface
• Acknowledgments
• About the Author
• List of Acronyms
• About the Companion Websites
• Part One FSSM: Introduction
• Part Two FSSM: Software View
• Part Three FSSM: Measurements
• Part Four FSSM: Estimations and Indications
• Part Five FSSM: Summary Charts
• Part Six FSSM: Strengths
• Part Seven FSSM: Usage - Example
• Part Eight Concluding Information
• Part Nine Glossary
• Part Ten List of Figures and Answers to Exercises
• References
• Index
• EULA