ISO/IEC 20926:2009
(Main)Software and systems engineering — Software measurement — IFPUG functional size measurement method 2009
Software and systems engineering — Software measurement — IFPUG functional size measurement method 2009
ISO/IEC 20926:2009 specifies the set of definitions, rules and steps for applying the IFPUG (International Function Point Users Group) functional size measurement (FSM) method. ISO/IEC 20926:2009 is conformant with all mandatory provisions of ISO/IEC 14143-1:2007. It can be applied to all functional domains and is fully convertible to prior editions of IFPUG sizing methods. IFPUG function point analysts have identified different delivery rates (hours to deliver a function point) related to building applications in different functional domains calibrated for varying project sizes and software complexities. ISO/IEC 20926:2009 can be applied by anyone requiring a measurement of functional size. Persons experienced with the method will find ISO/IEC 20926:2009 to be a useful reference.
Ingénierie du logiciel et des systèmes — Mesurage du logiciel — Méthode IFPUG 2009 de mesurage de la taille fonctionnelle
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INTERNATIONAL ISO/IEC
STANDARD 20926
Second edition
2009-12-01
Software and systems engineering —
Software measurement — IFPUG
functional size measurement
method 2009
Ingénierie du logiciel et des systèmes — Mesurage du logiciel —
Méthode IFPUG 2009 de mesurage de la taille fonctionnelle
Reference number
©
ISO/IEC 2009
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO/IEC 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2009 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
1.1 Purpose .1
1.2 Conformity .1
1.3 Applicability .1
1.4 Audience .1
2 Normative references.1
3 Terms and definitions .2
4 Abbreviated terms.8
5 Measurement Process .8
5.1 Overview.8
5.2 Gather the available documentation .9
5.3 Determine the counting scope and boundary and identify Functional User Requirements .9
5.4 Measure data functions .10
5.5 Measure transactional functions .13
5.6 Measure conversion functionality .19
5.7 Measure enhancement functionality .19
5.8 Calculate functional size .19
5.9 Document the function point count.21
5.10 Report the result of the function point count.21
Annex A (informative) Consolidated complexity and functional size tables.23
Bibliography.24
© ISO/IEC 2009 – All rights reserved iii
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 20926 was prepared by the International Function Point Users Group (IFPUG) and was adopted,
under the PAS procedure, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel
with its approval by national bodies of ISO and IEC.
This second edition cancels and replaces the first edition (ISO/IEC 20926:2003), which has been technically
revised.
iv © ISO/IEC 2009 – All rights reserved
Introduction
The use of function points, as a measure of the functional size of software, has grown since the mid 1970s
from a few interested organizations to an impressive list of organizations worldwide. Allan Albrecht was the
first to publicly release a method for functionally sizing software called function point analysis. With the growth
in the use of function points, there has been wider application and use of the measure. Since its formation in
1986 the International Function Point Users Group (IFPUG) has continuously enhanced the original Albrecht
method for functionally sizing software. This International Standard is the latest release in the continually
improving IFPUG method that promotes the consistent interpretation of functional size measurement in
conformance with ISO/IEC 14143-1:2007. The IFPUG functional size measurement method is known as
function point analysis and its units of functional size are called Function Points.
Organizations can apply this International Standard to measure the size of a software product to:
⎯ support quality and productivity analysis;
⎯ estimate cost and resources required for software development, enhancement and maintenance;
⎯ provide a normalization factor for software comparison;
⎯ determine the size of a purchased application package by functionally sizing all the functions included in
the package;
⎯ assist users in determining the benefit of an application package to their organization by functionally
sizing functions that specifically match their requirements.
Function point analysis measures software by quantifying the tasks and services (i.e., functionality) that the
software provides to the user based primarily on logical design. The objectives of function point analysis are to
measure:
⎯ functionality implemented in software, that the user requests and receives;
⎯ functionality impacted by software development, enhancement and maintenance independently of
technology used for implementation.
The process of function point analysis is:
⎯ simple enough to minimize the overhead of the measurement process;
⎯ a consistent measure among various projects and organizations.
In order to effectively apply this International Standard, persons can be formally trained in the method using
IFPUG certified course materials.
This International Standard is one component in the IFPUG publications. It is recommended that it be read in
conjunction with the other IFPUG publications. These provide guidance to application of the rules specified
within this International Standard and background information to aid in understanding the use and applicability
of the resulting functional size. Supporting IFPUG publications include the following:
⎯ the current version of the IFPUG Counting Practices Manual, which incorporates this International
Standard supplemented with counting practices and examples that support its implementation;
© ISO/IEC 2009 – All rights reserved v
⎯ “Framework for Functional Sizing”, 2005, which discusses the contribution of both functional size and
non-functional size to the overall software product size; the IFPUG FSM method is a method for
measuring the functional size;
⎯ IFPUG website at www.ifpug.org.
vi © ISO/IEC 2009 – All rights reserved
INTERNATIONAL STANDARD ISO/IEC 20926:2009(E)
Software and systems engineering — Software measurement —
IFPUG functional size measurement method 2009
1 Scope
1.1 Purpose
This International Standard specifies the set of definitions, rules and steps for applying the IFPUG functional
size measurement (FSM) method.
1.2 Conformity
This International Standard is conformant with all mandatory provisions of ISO/IEC 14143-1:2007.
1.3 Applicability
This International Standard can be applied to all functional domains.
NOTE IFPUG continues to publish white papers providing guidelines for use in evolving environments and domains.
This International Standard is fully convertible to prior editions of IFPUG sizing methods.
IFPUG function point analysts have identified different delivery rates (hours to deliver a function point) related
to building applications in different functional domains calibrated for varying project sizes and software
complexities.
1.4 Audience
This International Standard can be applied by anyone requiring a measurement of functional size. Persons
experienced with the method will find this International Standard to be a useful reference.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 14143-1:2007, Information technology — Software measurement — Functional size measurement —
Part 1: Definition of concepts
© ISO/IEC 2009 – All rights reserved 1
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adaptive maintenance
modification of a software product, performed after delivery, to keep a software product usable in a changed
or changing environment
NOTE Adaptive maintenance provides enhancements necessary to accommodate changes in the environment in
which a software product must operate. These changes are those that must be made to keep pace with the changing
environment. For example, the operating system might be upgraded and some changes may be made to accommodate
the new operating system.
[ISO/IEC 14764:2006, 3.1]
3.2
application
cohesive collection of automated procedures and data supporting a business objective, consisting of one or
more components, modules, or subsystems
EXAMPLES Accounts payable, accounts receivable, payroll, procurement, shop production, assembly line control, air
search radar, target tracking, weapons firing, flight line scheduling and passenger reservations.
3.3
application functional size
measure of the functionality that an application provides to the user, determined by the application function
point count
3.4
application function point count
activity of applying this International Standard to measure the functional size of an application
3.5
arranging
activity of sequencing attributes in a transactional function
3.6
associative entity type
entity type that contains attributes which further describe a many-to-many relationship between two other
entity types
3.7
attributive entity type
entity type that further describes one or more attributes of another entity type
3.8
base functional component
BFC
elementary unit of Functional User Requirements defined by and used by an FSM Method for measurement
purposes
EXAMPLE A Functional User Requirement could be “Maintain Customers”, which might consist of the following
BFCs: “Add a new customer”, “Report Customer Purchases”, and “Change Customer Details”. Another example might
include a collection of logically related business data maintained by the software under study such as “Customer Details”.
There are many other examples.
[ISO/IEC 14143-1:2007, 3.1]
2 © ISO/IEC 2009 – All rights reserved
3.9
boundary
conceptual interface betwe
...
INTERNATIONAL ISO/IEC
STANDARD 20926
Second edition
2009-12-01
Software and systems engineering —
Software measurement — IFPUG
functional size measurement
method 2009
Ingénierie du logiciel et des systèmes — Mesurage du logiciel —
Méthode IFPUG 2009 de mesurage de la taille fonctionnelle
Reference number
©
ISO/IEC 2009
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO/IEC 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2009 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
1.1 Purpose .1
1.2 Conformity .1
1.3 Applicability .1
1.4 Audience .1
2 Normative references.1
3 Terms and definitions .2
4 Abbreviated terms.8
5 Measurement Process .8
5.1 Overview.8
5.2 Gather the available documentation .9
5.3 Determine the counting scope and boundary and identify Functional User Requirements .9
5.4 Measure data functions .10
5.5 Measure transactional functions .13
5.6 Measure conversion functionality .19
5.7 Measure enhancement functionality .19
5.8 Calculate functional size .19
5.9 Document the function point count.21
5.10 Report the result of the function point count.21
Annex A (informative) Consolidated complexity and functional size tables.23
Bibliography.24
© ISO/IEC 2009 – All rights reserved iii
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 20926 was prepared by the International Function Point Users Group (IFPUG) and was adopted,
under the PAS procedure, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel
with its approval by national bodies of ISO and IEC.
This second edition cancels and replaces the first edition (ISO/IEC 20926:2003), which has been technically
revised.
iv © ISO/IEC 2009 – All rights reserved
Introduction
The use of function points, as a measure of the functional size of software, has grown since the mid 1970s
from a few interested organizations to an impressive list of organizations worldwide. Allan Albrecht was the
first to publicly release a method for functionally sizing software called function point analysis. With the growth
in the use of function points, there has been wider application and use of the measure. Since its formation in
1986 the International Function Point Users Group (IFPUG) has continuously enhanced the original Albrecht
method for functionally sizing software. This International Standard is the latest release in the continually
improving IFPUG method that promotes the consistent interpretation of functional size measurement in
conformance with ISO/IEC 14143-1:2007. The IFPUG functional size measurement method is known as
function point analysis and its units of functional size are called Function Points.
Organizations can apply this International Standard to measure the size of a software product to:
⎯ support quality and productivity analysis;
⎯ estimate cost and resources required for software development, enhancement and maintenance;
⎯ provide a normalization factor for software comparison;
⎯ determine the size of a purchased application package by functionally sizing all the functions included in
the package;
⎯ assist users in determining the benefit of an application package to their organization by functionally
sizing functions that specifically match their requirements.
Function point analysis measures software by quantifying the tasks and services (i.e., functionality) that the
software provides to the user based primarily on logical design. The objectives of function point analysis are to
measure:
⎯ functionality implemented in software, that the user requests and receives;
⎯ functionality impacted by software development, enhancement and maintenance independently of
technology used for implementation.
The process of function point analysis is:
⎯ simple enough to minimize the overhead of the measurement process;
⎯ a consistent measure among various projects and organizations.
In order to effectively apply this International Standard, persons can be formally trained in the method using
IFPUG certified course materials.
This International Standard is one component in the IFPUG publications. It is recommended that it be read in
conjunction with the other IFPUG publications. These provide guidance to application of the rules specified
within this International Standard and background information to aid in understanding the use and applicability
of the resulting functional size. Supporting IFPUG publications include the following:
⎯ the current version of the IFPUG Counting Practices Manual, which incorporates this International
Standard supplemented with counting practices and examples that support its implementation;
© ISO/IEC 2009 – All rights reserved v
⎯ “Framework for Functional Sizing”, 2005, which discusses the contribution of both functional size and
non-functional size to the overall software product size; the IFPUG FSM method is a method for
measuring the functional size;
⎯ IFPUG website at www.ifpug.org.
vi © ISO/IEC 2009 – All rights reserved
INTERNATIONAL STANDARD ISO/IEC 20926:2009(E)
Software and systems engineering — Software measurement —
IFPUG functional size measurement method 2009
1 Scope
1.1 Purpose
This International Standard specifies the set of definitions, rules and steps for applying the IFPUG functional
size measurement (FSM) method.
1.2 Conformity
This International Standard is conformant with all mandatory provisions of ISO/IEC 14143-1:2007.
1.3 Applicability
This International Standard can be applied to all functional domains.
NOTE IFPUG continues to publish white papers providing guidelines for use in evolving environments and domains.
This International Standard is fully convertible to prior editions of IFPUG sizing methods.
IFPUG function point analysts have identified different delivery rates (hours to deliver a function point) related
to building applications in different functional domains calibrated for varying project sizes and software
complexities.
1.4 Audience
This International Standard can be applied by anyone requiring a measurement of functional size. Persons
experienced with the method will find this International Standard to be a useful reference.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 14143-1:2007, Information technology — Software measurement — Functional size measurement —
Part 1: Definition of concepts
© ISO/IEC 2009 – All rights reserved 1
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adaptive maintenance
modification of a software product, performed after delivery, to keep a software product usable in a changed
or changing environment
NOTE Adaptive maintenance provides enhancements necessary to accommodate changes in the environment in
which a software product must operate. These changes are those that must be made to keep pace with the changing
environment. For example, the operating system might be upgraded and some changes may be made to accommodate
the new operating system.
[ISO/IEC 14764:2006, 3.1]
3.2
application
cohesive collection of automated procedures and data supporting a business objective, consisting of one or
more components, modules, or subsystems
EXAMPLES Accounts payable, accounts receivable, payroll, procurement, shop production, assembly line control, air
search radar, target tracking, weapons firing, flight line scheduling and passenger reservations.
3.3
application functional size
measure of the functionality that an application provides to the user, determined by the application function
point count
3.4
application function point count
activity of applying this International Standard to measure the functional size of an application
3.5
arranging
activity of sequencing attributes in a transactional function
3.6
associative entity type
entity type that contains attributes which further describe a many-to-many relationship between two other
entity types
3.7
attributive entity type
entity type that further describes one or more attributes of another entity type
3.8
base functional component
BFC
elementary unit of Functional User Requirements defined by and used by an FSM Method for measurement
purposes
EXAMPLE A Functional User Requirement could be “Maintain Customers”, which might consist of the following
BFCs: “Add a new customer”, “Report Customer Purchases”, and “Change Customer Details”. Another example might
include a collection of logically related business data maintained by the software under study such as “Customer Details”.
There are many other examples.
[ISO/IEC 14143-1:2007, 3.1]
2 © ISO/IEC 2009 – All rights reserved
3.9
boundary
conceptual interface betwe
...
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