ISO/IEC 25000:2005

INTERNATIONAL ISO/IEC
STANDARD 25000
First edition
2005-08-01


Software engineering — Software
product Quality Requirements and
Evaluation (SQuaRE) — Guide to SQuaRE
Ingénierie du logiciel — Exigences de qualité du produit logiciel et
évaluation (SQuaRE) — Guide de SQuaRE




Reference number
ISO/IEC 25000:2005(E)
©
ISO/IEC 2005

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ISO/IEC 25000:2005(E)
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ISO/IEC 25000:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Conformance. 1
3 Normative references . 1
4 Terms and definitions. 1
5 SQuaRE: Software product Quality Requirements and Evaluation – the series of
standards on product quality requirements and evaluation. 10
5.1 Organisation of SQuaRE series of standards. 10
5.2 SQuaRE: overview of documents within series . 11
5.3 SQuaRE common models. 12
Annex A (informative) Relationship between SQuaRE series and other ISO Standards. 16
A.1 ISO/IEC 12207:1995/Amd 1:2002 . 16
A.2 ISO/IEC 15504. 16
A.3 ISO 9000 family of standards. 16
A.4 ISO/IEC 15939. 19
A.5 ISO/IEC 15288. 19
Annex B (informative) Overview of ISO/IEC 14598 and ISO/IEC 9126. 21
B.1 Overview of ISO/IEC 14598 and ISO/IEC 9126 . 21
B.2 Quality model framework. 22
B.3 Evaluation process. 23
B.4 Support for evaluation. 24
B.5 Software quality characteristics and metrics . 24
B.6 The evaluation process. 26
Annex C (informative) History and transition process between ISO/IEC 9126, ISO/IEC 14598 and
SQuaRE series of standards . 34
C.1 History. 34
C.2 Relationship between ISO/IEC 9126 and ISO/IEC 14598 series and SQuaRE series of
standards. 35
Annex D (informative) Examples of the application of SQuaRE series of standards . 37
Bibliography . 40

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ISO/IEC 25000:2005(E)
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 25000 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 7, Software and system engineering.
ISO/IEC 25050 to ISO/IEC 25099 are reserved to be used for SQuaRE extension International Standards
and/or Technical Reports.
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ISO/IEC 25000:2005(E)
Introduction
Computers are being used in an increasingly wide variety of application areas, and their intended and correct
operation is often critical for business success and/or human safety. Developing or selecting high quality
software products is therefore of prime importance. Comprehensive specification and evaluation of software
product quality is a key factor in ensuring adequate quality. This can be achieved by defining appropriate
quality characteristics, while taking account of the intended use of the software product. It is important that
every relevant software product quality characteristic is specified and evaluated, whenever possible using
validated or widely accepted measures.
As quality characteristics and associated measures can be useful not only for evaluating a software product
but also for defining quality requirements, the predecessor of SQuaRE, ISO/IEC 9126:1991 has been
replaced by two related multipart International Standards: ISO/IEC 9126 (Software product quality) and
ISO/IEC 14598 (Software product evaluation). The following points derived from practical use of both series
gave the logical impulse for creating the new SQuaRE series of International Standards:
• Both ISO/IEC 9126 and ISO/IEC 14598 have common normative, referential and functional roots,
• ISO/IEC 9126 and ISO/IEC 14598 form a complementary set of standards,
• The independent life cycles of both series have created inconsistencies between them.
The general goal of creating the SQuaRE set of International Standards is to move to a logically organized,
enriched and unified series covering two main processes: software quality requirements specification and
software quality evaluation, supported by a software quality measurement process. The purpose of the
SQuaRE set of International Standards is to assist those developing and acquiring software products with the
specification and evaluation of quality requirements. It establishes criteria for the specification of software
product quality requirements, their measurement, and evaluation. It includes a two-part quality model for
aligning customer definitions of quality with attributes of the development process. In addition, the series
provides recommended measures of software product quality attributes that can be used by developers,
acquirers, and evaluators.
It has to be stressed that the SQuaRE series of International Standards is dedicated to software product
quality only. SQuaRE ISO/IEC 25000n — Quality Management Division addresses software product quality
requirements specification, measurement and evaluation, and is separate and distinct from the "Quality
Management" of processes, which is defined in the ISO 9000 family of standards.
The major benefits of the SQuaRE series over its predecessor standards include:
• the coordination of guidance on software product quality measurement and evaluation,
• guidance for the specification of software product quality requirements, and
• harmonization with ISO/IEC 15939 in the form of Software product Quality Measurement Reference
Model presented in ISO/IEC 25020 - Software engineering - Software product Quality Requirements and
Evaluation (SQuaRE) Measurement reference model and guide.
The major differences between ISO/IEC 9126, ISO/IEC 14598 and SQuaRE series of International Standards
are:
• the introduction of the new general reference model,
• the introduction of dedicated, detailed guides for each division,
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ISO/IEC 25000:2005(E)
• the introduction of Quality Measure elements within Quality Measurement Division,
• the introduction of the Quality Requirements Division,
• incorporation and revision of the evaluation processes,
• the introduction of guidance of practical use in form of examples,
• coordination and harmonization of the content with ISO/IEC 15939.
SQuaRE consists of the following five divisions:
• ISO/IEC 2500n - Quality Management Division,
• ISO/IEC 2501n - Quality Model Division,
• ISO/IEC 2502n - Quality Measurement Division,
• ISO/IEC 2503n - Quality Requirements Division, and
• ISO/IEC 2504n - Quality Evaluation Division,
ISO/IEC 25050 to ISO/IEC 25099 are reserved to be used for SQuaRE extension International Standards
and/or Technical Reports.
SQuaRE provides:
• Terms and definitions,
• Reference models,
• General guide,
• Individual division guides, and
• International Standards for requirements specification, planning and management, measurement and
evaluation purposes.
SQuaRE includes International Standards on quality model and measures, as well as on quality requirements
and evaluation.
SQuaRE replaces the current ISO/IEC 9126 series and the 14598 series.
This part of SQuaRE series of standards is a new International Standard with the goal of providing a common
set of reference models, terminology, definitions and guidance for practical use of the associated standards
and technical reports.

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INTERNATIONAL STANDARD ISO/IEC 25000:2005(E)

Software engineering — Software product Quality
Requirements and Evaluation (SQuaRE) — Guide to SQuaRE
1 Scope
This International Standards provides guidance for the use of the new series of International Standards
named Software product Quality Requirements and Evaluation (SQuaRE). The purpose of this Guide is to
provide a general overview of SQuaRE contents, common reference models and definitions, as well as the
relationship among the documents, allowing users of the Guide a good understanding of those series of
standards, according to their purpose of use. This document contains an explanation of the transition process
between the old ISO/IEC 9126 and the 14598 series and SQuaRE and also presents information on how to
use the ISO/IEC 9126 and 14598 series in their previous form.
SQuaRE series of standards is intended for, but not limited to, developers, acquirers and independent
evaluators of software products, particularly those responsible for defining software quality requirements and
for software product evaluation. It is recommended that users of the SQuaRE as well as ISO/IEC 14598 and
9126 series of standards also use this International Standard as a guide to execute their tasks.
2 Conformance
There is no particular conformance clause for this document. Users, for their intended use of SQuaRE series
of Standards should follow individual conformance clauses stated in each document of the series.
3 Normative references
This International Standard does not require any normative references. All informative references are
presented in the Bibliography.
4 Terms and definitions
For the purposes of this document, the following definitions apply.
NOTE The definitions are common to all parts of SQuaRE series of standards.
4.1
acquirer
individual or organisation that acquires or procures a system, software product or software service from a
supplier
NOTE Based on the definition in ISO/IEC 12207:1995.
4.2
analysis model
algorithm or calculation combining one or more base and/or derived measures with associated decision
criteria
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ISO/IEC 25000:2005(E)
4.3
attribute
inherent property or characteristic of an entity that can be distinguished quantitatively or qualitatively by
human or automated means
NOTE 1 Based on ISO/IEC 15939:2002.
NOTE 2 ISO 9000 distinguishes two types of attributes: a permanent characteristic existing inherently in something;
and an assigned characteristic of a product, process or system (e.g. the price of a product, the owner of a product). The
assigned characteristic is not an inherent quality characteristic of that product, process or system.
4.4
attribute for quality measure
attribute that relates to software product itself, to the use of the software product or to its development process
NOTE Attributes for quality measure are used in order to obtain quality measure elements.
4.5
base measure
measure defined in terms of an attribute and the method for quantifying it
NOTE A base measure is functionally independent of other measures.
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993].
4.6
commercial-off-the-shelf software product
software product defined by a market-driven need, commercially available, and whose fitness for use has
been demonstrated by a broad spectrum of commercial users
4.7
context of use
users, tasks, equipment (hardware, software and materials), and the physical and social environments in
which a product is used
[ISO 9241-11:1998]
4.8
custom software
software product developed for a specific application from a user requirements specification
4.9
data
collection of values assigned to base measures, derived measures and/or indicators
[ISO/IEC 15939:2002]
4.10
decision criteria
thresholds, targets, or patterns used to determine the need for action or further investigation, or to describe
the level of confidence in a given result
[ISO/IEC 15939:2002]
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ISO/IEC 25000:2005(E)
4.11
derived measure
measure that is defined as a function of two or more values of base measures
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993].
NOTE A transformation of a base measure using a mathematical function can also be considered as a derived
measure.
4.12
developer
individual or organisation that performs development activities (including requirements analysis, design,
testing through acceptance) during the software life cycle process
NOTE Based on the definition in ISO/IEC 12207:1995.
4.13
division of standards
division forms a family of standards serving complementary purposes
4.14
end user
individual person who ultimately benefits from the outcomes of the system
NOTE The end user may be a regular operator of the software product or a casual user such as a member of the
public.
4.15
entity
object that is to be characterised by measuring its attributes
EXAMPLE An object can be a process, product, project, or resource.
[ISO/IEC 15939:2002]
4.16
evaluation method
procedure describing actions to be performed by the evaluator in order to obtain results for the specified
measurement applied to the specified product components or on the product as a whole
4.17
evaluation module
package of evaluation technology for measuring software quality characteristics, subcharacteristics or
attributes
NOTE The package includes evaluation methods and techniques, inputs to be evaluated, data to be measured and
collected and supporting procedures and tools.
4.18
evaluator
individual or organisation that performs an evaluation
4.19
external software quality
capability of a software product to enable the behaviour of a system to satisfy stated and implied needs when
the system is used under specified conditions
NOTE Attributes of the behaviour can be verified and/or validated by executing the software product during testing
and operation.
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ISO/IEC 25000:2005(E)
EXAMPLE The number of failures found during testing is an external software quality measure related to the number
of faults present in the program. The two measures are not necessarily identical since testing may not find all faults, and a
fault may give rise to apparently different failures in different circumstances.
4.20
failure
termination of the ability of a product to perform a required function or its inability to perform within previously
specified limits
NOTE Based on the definition in IEEE 610.12-1990.
4.21
fault
incorrect step, process or data definition in a computer program
[IEEE 610.12-1990]
4.22
functional requirement
requirement that specifies a function that a system or system component must be able to perform
[IEEE 610.12-1990]
NOTE The software quality characteristic “functionality” can be used to specify or evaluate the suitability, accuracy,
interoperability, security and compliance of a function (see ISO/IEC 9126-1 [ISO/IEC 25010]).
4.23
implied needs
needs that may not have been stated but are actual needs
NOTE Some implied needs only become evident when the software product is used in particular conditions.
EXAMPLE Implied needs include: needs not stated but implied by other stated needs and needs not stated because
they are considered to be evident or obvious.
4.24
indicator
measure that provides an estimate or evaluation of specified attributes derived from a model with respect to
defined information needs
[ISO/IEC 15939:2002]
NOTE In ISO/IEC 14598 this definition was: "a measure that can be used to estimate or predict another measure".
4.25
information need
insight necessary to manage objectives, goals, risks, and problems
[ISO/IEC 15939:2002]
4.26
information product
one or more indicators and their associated interpretations that address information need
EXAMPLE A comparison of a measured defect rate to planned defect rate along with an assessment of whether or
not the difference indicates a problem.
[ISO/IEC 15939:2002]
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ISO/IEC 25000:2005(E)
4.27
information system needs
needs that can be specified as quality requirements by external measures and sometimes by internal
measures
4.28
intermediate software product
product of the software development process that is used as input to another stage of the software
development process
EXAMPLE Intermediate software products can include static and dynamic models, other documents and source
code.
4.29
intermediate software product needs
needs that can be specified as quality requirements by internal measures
4.30
internal software quality
capability of a set of static attributes of a software product to satisfy stated and implied needs when the
software product is used under specified conditions
NOTE 1 Static attributes include those that relate to the software architecture, structure and its components.
NOTE 2 Static attributes can be verified by review, inspection and/or automated tools.
EXAMPLE The number of lines of code, complexity measures and the number of faults found in a walk through are
all internal software quality measures made on the product itself.
4.31
maintainer
individual or organisation that performs maintenance activities
NOTE Based on the definition in ISO/IEC 12207:1995.
4.32
measure (noun)
variable to which a value is assigned as the result of measurement
NOTE The term “measures” is used to refer collectively to base measures, derived measures, and indicators.
[ISO/IEC 15939:2002]
4.33
measure (verb)
make a measurement
[ISO/IEC 14598-1:1999]
4.34
measurement
set of operations having the object of determining a value of a measure
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993]
NOTE Measurement can include assigning a qualitative category such as the language of a source program (ADA, C,
COBOL, etc.).
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ISO/IEC 25000:2005(E)
4.35
measurement function
algorithm or calculation performed to combine two or more base measures
[ISO/IEC 15939:2002]
4.36
measurement method
logical sequence of operations, described generically, used in quantifying an attribute with respect to a
specified scale
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993].
4.37
measurement procedure
set of operations, described specifically, used in the performance of a particular measurement according to a
given method
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993]
4.38
measurement process
process for establishing, planning, performing and evaluating software measurement within an overall project
or organisational measurement structure
[ISO/IEC 15939:2002]
4.39
observation
instance of applying a measurement procedure to produce a value for a base measure
[ISO/IEC 15939:2002]
4.40
operator
individual or organisation that operates the system
NOTE Based on the definition in ISO/IEC 12207:1995.
4.41
process
system of activities, which use resources to transform inputs into outputs
[ISO 9000:2000]
4.42
quality in use (measure)
the extent to which a product used by specific users meets their needs to achieve specific goals with
effectiveness, productivity, safety and satisfaction in specific contexts of use
4.43
quality measure elements
measure, which is either a base measure or a derived measure, that is used for constructing software quality
measures
NOTE The software quality characteristic or subcharacteristic of the entity is derived afterwards by calculating a
software quality measure.
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ISO/IEC 25000:2005(E)
4.44
quality model
defined set of characteristics, and of relationships between them, which provides a framework for specifying
quality requirements and evaluating quality
4.45
rating
action of mapping the measured value to the appropriate rating level. Used to determine the rating level
associated with the software product for a specific quality characteristic
4.46
rating level
scale point on an ordinal scale, which is used to categorise a measurement scale
NOTE 1 The rating level enables software product to be classified (rated) in accordance with the stated or implied
needs.
NOTE 2 Appropriate rating levels may be associated with the different views of quality i.e. Users', Managers' or
Developers'.
4.47
requirements
expression of a perceived need that something be accomplished or realized
NOTE The requirements may be specified as part of a contract, or specified by the development organisation, as
when a product is developed for unspecified users, such as consumer software, or the requirements may be more general,
as when a user evaluates products for comparison and selection purpose.
4.48
scale
ordered set of values, continuous or discrete, or a set of categories to which the attribute is mapped
[ISO/IEC 15939:2002, based on the definition in International Vocabulary of Basic and General Terms in
Metrology, 1993]
EXAMPLE Types of scales are: a nominal scale which corresponds to a set of categories; an ordinal scale which
corresponds to an ordered set of scale points; an interval scale which corresponds to an ordered scale with equidistant
scale points; and a ratio scale which not only has equidistant scale point but also possesses an absolute zero. Measures
using nominal or ordinal scales produce qualitative data, and measures using interval and ratio scales produce
quantitative data.
4.49
software product
set of computer programs, procedures, and possibly associated documentation and data
[ISO/IEC 12207:1995]
NOTE 1 Products include intermediate products, and products intended for users such as developers and maintainers.
NOTE 2 In SQuaRE standards software quality has the same meaning as software product quality.
4.50
software product evaluation
technical operation that consists of producing an assessment of one or more characteristics of a software
product according to a specified procedure
4.51
software quality
capability of software product to satisfy stated and implied needs when used under specified conditions
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ISO/IEC 25000:2005(E)
NOTE This definitions differs from the ISO 9000:2000 quality definition mainly because the software quality definition
refers to the satisfaction of stated and implied needs, while the ISO 9000 quality definition refers to the satisfaction of
requirements.
4.52
software quality characteristic
category of software quality attributes that bears on software quality
NOTE Software quality characteristics may be refined into multiple levels of subcharacteristics and finally into
software quality attributes.
4.53
software quality evaluation
systematic examination of the extent to which a software product is capable of satisfying stated and implied
needs
4.54
software quality in use
capability of the software product to enable specific users to achieve specific goals with effectiveness,
productivity, safety and satisfaction in specific contexts of use
NOTE Before the product is released, quality in use can be specified and measured in a test environment for the
intended users, goals and contexts of use. Once in use, it can be measured for actual users, goals and contexts of
use. The actual needs of users may not be the same as those anticipated in requirements, so actual quality in use may be
different from quality in use measured earlier in a test environment.
4.55
software quality measure
measure of internal software quality, external software quality or software quality in use
NOTE Internal software quality, external software quality and software quality in use are described in the quality
model in ISO/IEC 9126-1 [ISO/IEC 25010].
4.56
stakeholder
a party having a right, sha
...