Information technology -- Systems and software Quality Requirements and Evaluation (SQuaRE) -- Measurement of IT service quality

This document defines quality measures useful for requirements and evaluation of IT service quality in terms of characteristics and sub-characteristics defined in ISO/IEC TS 25011. This document contains a basic set of quality measures for each characteristic and sub-characteristic. This document does not assign ranges of values of the quality measures to rated levels or to grades of compliance. Such values are defined based on the nature of the IT service, and so depends on factors such as category of the IT service or users' needs. Some attributes can have a desirable range of values, which does not depend on specific user needs but generic factors, for example, service downtime. This document includes, in Annex A, considerations for the selection and application of quality measures. The quality measures in this document are primarily intended to be used for quality evaluation and improvement of IT services during or after the development life cycle. The main users of this document are people carrying out quality requirements specification and evaluation activities for IT services as part of the following: — development: including requirements analysis, design, implementation, testing and deployment during the development life cycle; — quality management: monitoring activities of quality assurance and performing quality control of an IT service; — supply: making a contract with the user for supplying an IT service under the terms of a contract; — acquisition: including IT service selection, when acquiring or procuring an IT service from a service provider; — maintenance: improvement of an IT service based on quality measurement. The relationship of this document to domain-specific IT service quality model and its precedence over this document is determined by the user in a specific context of use.

Technologies de l'information -- Exigences de qualité et évaluation des systèmes et du logiciel (SQuaRE) -- Mesure de la qualité du service informatique

General Information

Status
Published
Publication Date
14-Mar-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
15-Feb-2021
Completion Date
15-Feb-2021
Ref Project

Buy Standard

Technical specification
ISO/IEC TS 25025:2021 - Information technology -- Systems and software Quality Requirements and Evaluation (SQuaRE) -- Measurement of IT service quality
English language
23 pages
sale 15% off
Preview
sale 15% off
Preview
Draft
ISO/IEC PRF TS 25025:Version 30-jan-2021 - Information technology -- Systems and software Quality Requirements and Evaluation (SQuaRE) -- Measurement of IT service quality
English language
23 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

TECHNICAL ISO/IEC TS
SPECIFICATION 25025
First edition
2021-03
Information technology — Systems
and software Quality Requirements
and Evaluation (SQuaRE) —
Measurement of IT service quality
Technologies de l'information — Exigences de qualité et évaluation
des systèmes et du logiciel (SQuaRE) — Mesure de la qualité du
service informatique
Reference number
ISO/IEC TS 25025:2021(E)
ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC TS 25025:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC TS 25025:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Conformance ............................................................................................................................................................................................................. 3

5 Use of IT service quality measures .................................................................................................................................................... 3

5.1 IT service quality measurement concepts ...................................................................................................................... 3

5.2 Approach to IT service quality measurement .............................................................................................................. 3

6 Format used for documenting the IT service quality measures ......................................................................... 4

7 IT service quality measures ...................................................................................................................................................................... 4

7.1 General ........................................................................................................................................................................................................... 4

7.2 Suitability measures ........................................................................................................................................................................... 6

7.2.1 General...................................................................................................................................................................................... 6

7.2.2 Completeness measures ............................................................................................................................................ 6

7.2.3 Correctness measures ................................................................................................................................................. 6

7.2.4 Appropriateness measures ..................................................................................................................................... 7

7.2.5 Consistency measures ................................................................................................................................................. 7

7.3 Usability measures .............................................................................................................................................................................. 8

7.3.1 General...................................................................................................................................................................................... 8

7.3.2 Appropriateness recognizability measures .............................................................................................. 8

7.3.3 Learnability measures ................................................................................................................................................ 8

7.3.4 Operability measures ................................................................................................................................................... 9

7.3.5 User error protection measures ......................................................................................................................10

7.3.6 Accessibility measures ........................................................................................................................................... ..10

7.3.7 Courtesy measures ......................................................................................................................................................10

7.4 Security measures .............................................................................................................................................................................11

7.4.1 General...................................................................................................................................................................................11

7.4.2 Confidentiality measures .......................................................................................................................................11

7.4.3 Integrity measures ......................................................................................................................................................12

7.4.4 Traceability measures ..............................................................................................................................................12

7.5 IT service reliability measures ...............................................................................................................................................12

7.5.1 General...................................................................................................................................................................................12

7.5.2 Continuity measures ........................................................................................................................................... .......12

7.5.3 IT service recoverability measures ...............................................................................................................13

7.5.4 Availability measures ................................................................................................................................................14

7.6 Tangibility measures .......................................................................................................................................................................14

7.6.1 General...................................................................................................................................................................................14

7.6.2 Visibility measures ......................................................................................................................................................14

7.6.3 Professionalism measures ....................................................................................................................................14

7.6.4 IT service interface appearance measures .............................................................................................15

7.7 Responsiveness measures ..........................................................................................................................................................15

7.7.1 General...................................................................................................................................................................................15

7.7.2 Timeliness measures .................................................................................................................................................16

7.7.3 Reactiveness measures ............................................................................................................................................16

7.8 IT service adaptability measures .........................................................................................................................................16

7.8.1 General...................................................................................................................................................................................16

7.8.2 Customizability measures .....................................................................................................................................16

7.8.3 Initiative measures .................. ......................................................................................................................... ...........17

7.9 IT service maintainability measures .................................................................................................................................18

7.9.1 General...................................................................................................................................................................................18

7.9.2 Analysability measures ...........................................................................................................................................18

© ISO/IEC 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC TS 25025:2021(E)

7.9.3 Modifiability measures ............................................................................................................................................18

7.9.4 Testability measures ..................................................................................................................................................18

Annex A (Informative) Context of using the model and different IT service types ...........................................20

Bibliography .............................................................................................................................................................................................................................23

iv © ISO/IEC 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC TS 25025:2021(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for

the different types of document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives or www .iec .ch/ members

_experts/ refdocs).

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. Details of any patent rights identified during the development of the document will be in the

Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC

list of patent declarations received (see patents.iec.ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html. In the IEC, see www .iec .ch/ understanding -standards.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 7, Software and systems engineering.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html and www .iec .ch/ national

-committees.
© ISO/IEC 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/IEC TS 25025:2021(E)
Introduction
0.1 General

This document is a part of the Systems and software Quality Requirements and Evaluation(SQuaRE)

series of documents, which provides a set of measures for the quality characteristics of IT service that

are defined in ISO/IEC TS 25011. It can be used for specifying requirements, measuring and evaluating

the IT service quality, in conjunction with other SQuaRE series of documents.

The set of quality measures in this document are selected based on their practical value. They are not

intended to be exhaustive, therefore users of this document are encouraged to refine them if necessary.

0.2 Quality measurement division

This document is a part of the ISO/IEC 2502n division that currently consists of the following documents:

— ISO/IEC 25020 — Quality measurement framework: provides a reference model and guideline for

measuring the quality characteristics defined in ISO/IEC 2501n quality model division.

— ISO/IEC 25021 — Quality measure elements: provides a format for specifying quality measure

elements and some examples of quality measure elements that can be used to construct software

quality measures.

— ISO/IEC 25022 — Measurement of quality in use: provides measures including associated

measurement functions for the quality characteristics in the quality in use model.

— ISO/IEC 25023 — Measurement of system and software product quality: provides measures including

associated measurement functions for the quality characteristics in the product quality model.

— ISO/IEC 25024 — Measurement of data quality: provides measures including associated

measurement functions for the quality characteristics in the data quality model.

— ISO/IEC TS 25025 — Measurement of IT service quality: provides quality measures useful for

requirements and evaluation of IT service quality.

Figure 1 depicts the relationship between this document and the other documents in the ISO/IEC 2502n

division.
vi © ISO/IEC 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC TS 25025:2021(E)
Figure 1 — Structure of the quality measurement division
0.3 Outline and organization of SQuaRE series

The SQuaRE series consists of five main divisions and an extension division. An outline of each division

within the SQuaRE series is as follows:

— ISO/IEC 2500n — Quality management division. The standards that form this division define all

common models, terms and definitions referred further by all other standards from the SQuaRE

series. The division also provides requirements and guidance for the planning and management of

a project.

— ISO/IEC 2501n — Quality model division. The standards that form this division provide quality

models for system/software products, quality in use, data and IT service. Practical guidance on the

use of the quality model is also provided.

— ISO/IEC 2502n — Quality measurement division. The standards that form this division include a

system/software product quality measurement reference model, definitions of quality measures,

and practical guidance for their application. This division presents internal measures of software

quality, external measures of software quality, quality in use measures, data quality measures

and IT service quality measures. Quality measure elements forming foundations for the quality

measures are defined and presented.

— ISO/IEC 2503n — Quality requirements division. The standards that form this division help to

specify quality requirements. These quality requirements can be used in the process of quality

requirements elicitation for a system/software product to be developed, designing a process for

achieving necessary quality, or as inputs for an evaluation process.

— ISO/IEC 2504n — Quality evaluation division. The standards that form this division provide

requirements, recommendations and guidelines for system/software product evaluation, whether

performed by independent evaluators, acquirers or developers. The support for documenting a

measure as an Evaluation Module is also presented.
© ISO/IEC 2021 – All rights reserved vii
---------------------- Page: 7 ----------------------
ISO/IEC TS 25025:2021(E)

ISO/IEC 25050 to ISO/IEC 25099 are reserved for SQuaRE extension International Standards, Technical

Specifications, Publicly Available Specifications (PAS) and/or Technical Reports.

viii © ISO/IEC 2021 – All rights reserved
---------------------- Page: 8 ----------------------
TECHNICAL SPECIFICATION ISO/IEC TS 25025:2021(E)
Information technology — Systems and software Quality
Requirements and Evaluation (SQuaRE) — Measurement of
IT service quality
1 Scope

This document defines quality measures useful for requirements and evaluation of IT service quality in

terms of characteristics and sub-characteristics defined in ISO/IEC TS 25011.

This document contains a basic set of quality measures for each characteristic and sub-characteristic.

This document does not assign ranges of values of the quality measures to rated levels or to grades of

compliance. Such values are defined based on the nature of the IT service, and so depends on factors

such as category of the IT service or users' needs. Some attributes can have a desirable range of values,

which does not depend on specific user needs but generic factors, for example, service downtime. This

document includes, in Annex A, considerations for the selection and application of quality measures.

The quality measures in this document are primarily intended to be used for quality evaluation and

improvement of IT services during or after the development life cycle.

The main users of this document are people carrying out quality requirements specification and

evaluation activities for IT services as part of the following:

— development: including requirements analysis, design, implementation, testing and deployment

during the development life cycle;

— quality management: monitoring activities of quality assurance and performing quality control of

an IT service;

— supply: making a contract with the user for supplying an IT service under the terms of a contract;

— acquisition: including IT service selection, when acquiring or procuring an IT service from a service

provider;
— maintenance: improvement of an IT service based on quality measurement.

The relationship of this document to domain-specific IT service quality model and its precedence over

this document is determined by the user in a specific context of use.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 25000, Systems and software engineering — Systems and software Quality Requirements and

Evaluation (SQuaRE) — Guide to SQuaRE

ISO/IEC TS 25011:2017, Information technology — Systems and software Quality Requirements and

Evaluation (SQuaRE) — Service quality models

ISO/IEC 25021:2012, Systems and software engineering — Systems and software Quality Requirements

and Evaluation (SQuaRE) — Quality measure elements
© ISO/IEC 2021 – All rights reserved 1
---------------------- Page: 9 ----------------------
ISO/IEC TS 25025:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 25000 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
quality measure

derived measure that is defined as a measurement function (3.5) of two or more values of quality

measure elements
[SOURCE: ISO/IEC 25021:2012, 4.13]
3.2
IT service
information technology service

service that makes use of IT systems as tools to provide value to an individual user or a business by

facilitating results the user or business wants to achieve

Note 1 to entry: IT services can be delivered remotely by people, or by an IT application that could be in a local or

remote location.

[SOURCE: ISO/IEC TS 25011:2017, 3.3.2, modified — "information technology service" has been changed

from a preferred term to an admitted term.]
3.3
IT service quality

degree to which an IT service (3.2) satisfies stated and implied needs when used under specified

conditions
[SOURCE: ISO/IEC TS 25011:2017, 3.3.10]
3.4
IT service function

collection of related steps performed as a part of an IT service (3.2), or features provided by an IT system

EXAMPLE The service status monitoring or data backup of an internet banking service.

Note 1 to entry: ISO/ IEC has software functionality identification, classification and sizing standard methods

that provides consistency identifying unique IT service functions; these include: ISO/IEC 20926 (IFPUG

method), ISO/IEC 19761 (COSMIC method), ISO/IEC 29881 (FiSMA method), ISO/IEC 20968 (MarkII method),

ISO/IEC 24570 (NESMA method).
3.5
measurement function

algorithm or calculation performed to combine two or more quality measure elements

[SOURCE: ISO/IEC 25021:2012, 4.7, modified — Note 1 to entry has been removed.]
3.6
service provider
organization that manages and delivers a service or services to customers
[SOURCE: ISO/IEC 20000-1:2018, 3.2.24]
2 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/IEC TS 25025:2021(E)
3.7
service level agreement
SLA

documented agreement between the IT service (3.2) provider and the user that identifies services and

their agreed performance

Note 1 to entry: A service level agreement can be included in a contract or another type of documented agreement.

[SOURCE: ISO/IEC 20000-1:2018, 3.2.20, modified — "the organization and the customer" has been

changed to "the IT service provide and the user"; the original note 1 to entry has been removed; the

original note 2 to entry has become note 1 to entry.]
4 Conformance

Any quality requirements specification or quality evaluation that conforms to this document shall:

a) select the quality characteristics and/or sub-characteristics to be specified or evaluated as defined

in ISO/IEC TS 25011;
b) provide the rationale for any modifications of quality measures;

c) define any additional quality measures and quality measure elements from ISO/IEC 25021 that are

not included in this document.
5 Use of IT service quality measures
5.1 IT service quality measurement concepts

This document provides quality measures for the characteristics and sub-characteristics of the

service quality model defined in ISO/IEC TS 25011. IT service quality characteristics are defined in

ISO/IEC TS 25011 that categorizes IT service quality into 8 characteristics.

The quality of an IT service is the degree of satisfying the stated and implied needs of its users and thus

provides value. These stated and implied needs are represented in the SQuaRE series of standards by

quality models that categorize IT service quality into characteristics, which in most cases are further

subdivided into sub-characteristics.

The quality characteristic and sub-characteristic can be quantified by applying measurement

functions. The measurement function of a quality measure is defined using a mathematical formula

by combining quality measure elements. Quality measures enable us to quantify the quality of an IT

service. More than one quality measure can be used for the measurement of quality characteristics and

sub-characteristics.
5.2 Approach to IT service quality measurement

This document provides a possible, suggested set of IT service quality measures to be used with the

quality model in ISO/IEC TS 25011. The user of this document can select suitable quality measures for

a specific service and assign different weighting to these quality measures for different types of IT

services.

When selecting the appropriate IT service quality measures, the factors which can influence the

selection can include the following:
— the importance of the property to quantify;
— the type of the target IT service;
— the user requirements.
© ISO/IEC 2021 – All rights reserved 3
---------------------- Page: 11 ----------------------
ISO/IEC TS 25025:2021(E)

If necessary, the user can modify the quality measures defined in this document and can also define

new measures or use ones from the other documents.

When using a newly defined or modified quality measure, the user should specify how the measure

relates to the ISO/IEC TS 25011 quality model or any other substitute quality model that is being used.

Most of the quality measures defined in this document use measurement functions which provide

normalized values ranging from 0 to 1. The users can change the value range, for example, low or high,

if it is desirable.
6 Format used for documenting the IT service quality measures
The following information is given for each quality measure in Tables 1 to 27:

a) ID: identification code of the quality measure. Each ID consists of the following two parts:

— abbreviated alphabetic code representing the quality characteristics as one capital X and sub-

characteristics as one capital X followed by lower-case x (for example, “UUe” denotes “User

error protection” measures for “Usability”);
— serial number in sequential order within quality sub-characteristic.
b) Name: quality measure name.
c) Description: the information provided by the quality measure.

d) Measurement function: mathematical formula showing how the quality measure elements are

combined to produce the quality measure.
7 IT service quality measures
7.1 General

The quality measures in this clause are listed by quality characteristics and sub-characteristics, in the

order used in ISO/IEC TS 25011; and the word “measures” in this clause means quality measures.

NOTE 1 The list of quality measures shown in Table 1 is not final, and can be revised in future editions of this

document. Users of this document are invited to provide feedback.
Table 1 — IT service quality measures
Characteristics Sub-characteristics Measures
Functional coverage
Completeness Goals and objectives achievement
Data items populated
IT service function correctness
Correctness
Suitability Compliance of defined process
IT service function appropriateness for context of use
Appropriateness
IT service function appropriateness to service users
IT service consistency
Consistency
IT service process quality consistency
4 © ISO/IEC 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO/IEC TS 25025:2021(E)
Table 1 (continued)
Characteristics Sub-characteristics Measures
Description completeness
Appropriateness
recognizability
Demonstration coverage
User guide completeness
Learnability User guide effectiveness
User guide efficiency
Message clarity
Understandable categorization of service
Usability Operability
IT service automation
Effort time estimability
Avoidance of user operation error
User error protection
User error correction
Accessibility for users with disabilities
Accessibility
Language supportability
Courtesy Courteous service language, behaviour and attitude
Access controllability
Completeness of access control methods to protect confi-
Confidentiality
dential information
Effectiveness of confidentiality protection
Security
Integrity Data integrity
User audit trail completeness
Traceability
Traceability completeness
Coverage of IT service continuity plan
Compl
...

TECHNICAL ISO/IEC TS
SPECIFICATION 25025
First edition
Information technology — Systems
and software Quality Requirements
and Evaluation (SQuaRE) —
Measurement of IT service quality
Technologies de l'information — Exigences de qualité et évaluation
des systèmes et du logiciel (SQuaRE) — Mesure de la qualité du
service informatique
PROOF/ÉPREUVE
Reference number
ISO/IEC TS 25025:2021(E)
ISO/IEC 2021
---------------------- Page: 1 ----------------------
ISO/IEC TS 25025:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC TS 25025:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Conformance ............................................................................................................................................................................................................. 3

5 Use of IT service quality measures .................................................................................................................................................... 3

5.1 IT service quality measurement concepts ...................................................................................................................... 3

5.2 Approach to IT service quality measurement .............................................................................................................. 3

6 Format used for documenting the IT service quality measures ......................................................................... 4

7 IT service quality measures ...................................................................................................................................................................... 4

7.1 General ........................................................................................................................................................................................................... 4

7.2 Suitability measures ........................................................................................................................................................................... 6

7.2.1 General...................................................................................................................................................................................... 6

7.2.2 Completeness measures ............................................................................................................................................ 6

7.2.3 Correctness measures ................................................................................................................................................. 6

7.2.4 Appropriateness measures ..................................................................................................................................... 7

7.2.5 Consistency measures ................................................................................................................................................. 7

7.3 Usability measures .............................................................................................................................................................................. 8

7.3.1 General...................................................................................................................................................................................... 8

7.3.2 Appropriateness recognizability measures .............................................................................................. 8

7.3.3 Learnability measures ................................................................................................................................................ 8

7.3.4 Operability measures ................................................................................................................................................... 9

7.3.5 User error protection measures ......................................................................................................................10

7.3.6 Accessibility measures ........................................................................................................................................... ..10

7.3.7 Courtesy measures ......................................................................................................................................................10

7.4 Security measures .............................................................................................................................................................................11

7.4.1 General...................................................................................................................................................................................11

7.4.2 Confidentiality measures .......................................................................................................................................11

7.4.3 Integrity measures ......................................................................................................................................................12

7.4.4 Traceability measures ..............................................................................................................................................12

7.5 IT service reliability measures ...............................................................................................................................................12

7.5.1 General...................................................................................................................................................................................12

7.5.2 Continuity measures ........................................................................................................................................... .......12

7.5.3 IT service recoverability measures ...............................................................................................................13

7.5.4 Availability measures ................................................................................................................................................14

7.6 Tangibility measures .......................................................................................................................................................................14

7.6.1 General...................................................................................................................................................................................14

7.6.2 Visibility measures ......................................................................................................................................................14

7.6.3 Professionalism measures ....................................................................................................................................14

7.6.4 IT service interface appearance measures .............................................................................................15

7.7 Responsiveness measures ..........................................................................................................................................................15

7.7.1 General...................................................................................................................................................................................15

7.7.2 Timeliness measures .................................................................................................................................................16

7.7.3 Reactiveness measures ............................................................................................................................................16

7.8 IT service adaptability measures .........................................................................................................................................16

7.8.1 General...................................................................................................................................................................................16

7.8.2 Customizability measures .....................................................................................................................................16

7.8.3 Initiative measures .................. ......................................................................................................................... ...........17

7.9 IT service maintainability measures .................................................................................................................................18

7.9.1 General...................................................................................................................................................................................18

7.9.2 Analysability measures ...........................................................................................................................................18

© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO/IEC TS 25025:2021(E)

7.9.3 Modifiability measures ............................................................................................................................................18

7.9.4 Testability measures ..................................................................................................................................................18

Annex A (Informative) Context of using the model and different IT service types ...........................................20

Bibliography .............................................................................................................................................................................................................................23

iv PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC TS 25025:2021(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for

the different types of document should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

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. Details of any patent rights identified during the development of the document will be in the

Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC

list of patent declarations received (see patents.iec.ch).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,

Subcommittee SC 7, Software and systems engineering.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
ISO/IEC TS 25025:2021(E)
Introduction
0.1 General

This document is a part of the Systems and software Quality Requirements and Evaluation(SQuaRE)

series of documents, which provides a set of measures for the quality characteristics of IT service that

are defined in ISO/IEC TS 25011. It can be used for specifying requirements, measuring and evaluating

the IT service quality, in conjunction with other SQuaRE series of documents.

The set of quality measures in this document are selected based on their practical value. They are not

intended to be exhaustive, therefore users of this document are encouraged to refine them if necessary.

0.2 Quality measurement division

This document is a part of the ISO/IEC 2502n division that currently consists of the following documents:

— ISO/IEC 25020 — Quality measurement framework: provides a reference model and guideline for

measuring the quality characteristics defined in ISO/IEC 2501n quality model division.

— ISO/IEC 25021 — Quality measure elements: provides a format for specifying quality measure

elements and some examples of quality measure elements that can be used to construct software

quality measures.

— ISO/IEC 25022 — Measurement of quality in use: provides measures including associated

measurement functions for the quality characteristics in the quality in use model.

— ISO/IEC 25023 — Measurement of system and software product quality: provides measures including

associated measurement functions for the quality characteristics in the product quality model.

— ISO/IEC 25024 — Measurement of data quality: provides measures including associated

measurement functions for the quality characteristics in the data quality model.

— ISO/IEC TS 25025 — Measurement of IT service quality: provides quality measures useful for

requirements and evaluation of IT service quality.

Figure 1 depicts the relationship between this document and the other documents in the ISO/IEC 2502n

division.
vi PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC TS 25025:2021(E)
Figure 1 — Structure of the quality measurement division
0.3 Outline and organization of SQuaRE series

The SQuaRE series consists of five main divisions and an extension division. An outline of each division

within the SQuaRE series is as follows:

— ISO/IEC 2500n — Quality management division. The standards that form this division define all

common models, terms and definitions referred further by all other standards from the SQuaRE

series. The division also provides requirements and guidance for the planning and management of

a project.

— ISO/IEC 2501n — Quality model division. The standards that form this division provide quality

models for system/software products, quality in use, data and IT service. Practical guidance on the

use of the quality model is also provided.

— ISO/IEC 2502n — Quality measurement division. The standards that form this division include a

system/software product quality measurement reference model, definitions of quality measures,

and practical guidance for their application. This division presents internal measures of software

quality, external measures of software quality, quality in use measures, data quality measures

and IT service quality measures. Quality measure elements forming foundations for the quality

measures are defined and presented.

— ISO/IEC 2503n — Quality requirements division. The standards that form this division help to

specify quality requirements. These quality requirements can be used in the process of quality

requirements elicitation for a system/software product to be developed, designing a process for

achieving necessary quality, or as inputs for an evaluation process.

— ISO/IEC 2504n — Quality evaluation division. The standards that form this division provide

requirements, recommendations and guidelines for system/software product evaluation, whether

performed by independent evaluators, acquirers or developers. The support for documenting a

measure as an Evaluation Module is also presented.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE vii
---------------------- Page: 7 ----------------------
ISO/IEC TS 25025:2021(E)

ISO/IEC 25050 to ISO/IEC 25099 are reserved for SQuaRE extension International Standards, Technical

Specifications, Publicly Available Specifications (PAS) and/or Technical Reports.

viii PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 8 ----------------------
TECHNICAL SPECIFICATION ISO/IEC TS 25025:2021(E)
Information technology — Systems and software Quality
Requirements and Evaluation (SQuaRE) — Measurement of
IT service quality
1 Scope

This document defines quality measures useful for requirements and evaluation of IT service quality in

terms of characteristics and sub-characteristics defined in ISO/IEC TS 25011.

This document contains a basic set of quality measures for each characteristic and sub-characteristic.

This document does not assign ranges of values of the quality measures to rated levels or to grades of

compliance. Such values are defined based on the nature of the IT service, and so depends on factors

such as category of the IT service or users' needs. Some attributes can have a desirable range of values,

which does not depend on specific user needs but generic factors, for example, service downtime. This

document includes, in Annex A, considerations for the selection and application of quality measures.

The quality measures in this document are primarily intended to be used for quality evaluation and

improvement of IT services during or after the development life cycle.

The main users of this document are people carrying out quality requirements specification and

evaluation activities for IT services as part of the following:

— development: including requirements analysis, design, implementation, testing and deployment

during the development life cycle;

— quality management: monitoring activities of quality assurance and performing quality control of

an IT service;

— supply: making a contract with the user for supplying an IT service under the terms of a contract;

— acquisition: including IT service selection, when acquiring or procuring an IT service from a service

provider;
— maintenance: improvement of an IT service based on quality measurement.

The relationship of this document to domain-specific IT service quality model and its precedence over

this document is determined by the user in a specific context of use.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 25000, Systems and software engineering — Systems and software Quality Requirements and

Evaluation (SQuaRE) — Guide to SQuaRE

ISO/IEC TS 25011:2017, Information technology — Systems and software Quality Requirements and

Evaluation (SQuaRE) — Service quality models

ISO/IEC 25021:2012, Systems and software engineering — Systems and software Quality Requirements

and Evaluation (SQuaRE) — Quality measure elements
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE 1
---------------------- Page: 9 ----------------------
ISO/IEC TS 25025:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 25000 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
quality measure

derived measure that is defined as a measurement function (3.5) of two or more values of quality

measure elements
[SOURCE: ISO/IEC 25021:2012, 4.13]
3.2
IT service
information technology service

service that makes use of IT systems as tools to provide value to an individual user or a business by

facilitating results the user or business wants to achieve

Note 1 to entry: IT services can be delivered remotely by people, or by an IT application that could be in a local or

remote location.

[SOURCE: ISO/IEC TS 25011:2017, 3.3.2, modified — "information technology service" has been changed

from a preferred term to an admitted term.]
3.3
IT service quality

degree to which an IT service (3.2) satisfies stated and implied needs when used under specified

conditions
[SOURCE: ISO/IEC TS 25011:2017, 3.3.10]
3.4
IT service function

collection of related steps performed as a part of an IT service (3.2), or features provided by an IT system

EXAMPLE The service status monitoring or data backup of an internet banking service.

Note 1 to entry: ISO/ IEC has software functionality identification, classification and sizing standard methods

that provides consistency identifying unique IT service functions; these include: ISO/IEC 20926 (IFPUG

method), ISO/IEC 19761 (COSMIC method), ISO/IEC 29881 (FiSMA method), ISO/IEC 20968 (MarkII method),

ISO/IEC 24570 (NESMA method).
3.5
measurement function

algorithm or calculation performed to combine two or more quality measure elements

[SOURCE: ISO/IEC 25021:2012, 4.7, modified — Note 1 to entry has been removed.]
3.6
service provider
organization that manages and delivers a service or services to customers
[SOURCE: ISO/IEC 20000-1:2018, 3.2.24]
2 PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/IEC TS 25025:2021(E)
3.7
service level agreement
SLA

documented agreement between the IT service (3.2) provider and the user that identifies services and

their agreed performance

Note 1 to entry: A service level agreement can be included in a contract or another type of documented agreement.

[SOURCE: ISO/IEC 20000-1:2018, 3.2.20, modified — "the organization and the customer" has been

changed to "the IT service provide and the user"; the original note 1 to entry has been removed; the

original note 2 to entry has become note 1 to entry.]
4 Conformance

Any quality requirements specification or quality evaluation that conforms to this document shall:

a) select the quality characteristics and/or sub-characteristics to be specified or evaluated as defined

in ISO/IEC TS 25011;
b) provide the rationale for any modifications of quality measures;

c) define any additional quality measures and quality measure elements from ISO/IEC 25021 that are

not included in this document.
5 Use of IT service quality measures
5.1 IT service quality measurement concepts

This document provides quality measures for the characteristics and sub-characteristics of the

service quality model defined in ISO/IEC TS 25011. IT service quality characteristics are defined in

ISO/IEC TS 25011 that categorizes IT service quality into 8 characteristics.

The quality of an IT service is the degree of satisfying the stated and implied needs of its users and thus

provides value. These stated and implied needs are represented in the SQuaRE series of standards by

quality models that categorize IT service quality into characteristics, which in most cases are further

subdivided into sub-characteristics.

The quality characteristic and sub-characteristic can be quantified by applying measurement

functions. The measurement function of a quality measure is defined using a mathematical formula

by combining quality measure elements. Quality measures enable us to quantify the quality of an IT

service. More than one quality measure can be used for the measurement of quality characteristics and

sub-characteristics.
5.2 Approach to IT service quality measurement

This document provides a possible, suggested set of IT service quality measures to be used with the

quality model in ISO/IEC TS 25011. The user of this document can select suitable quality measures for

a specific service and assign different weighting to these quality measures for different types of IT

services.

When selecting the appropriate IT service quality measures, the factors which can influence the

selection can include the following:
— the importance of the property to quantify;
— the type of the target IT service;
— the user requirements.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE 3
---------------------- Page: 11 ----------------------
ISO/IEC TS 25025:2021(E)

If necessary, the user can modify the quality measures defined in this document and can also define

new measures or use ones from the other documents.

When using a newly defined or modified quality measure, the user should specify how the measure

relates to the ISO/IEC TS 25011 quality model or any other substitute quality model that is being used.

Most of the quality measures defined in this document use measurement functions which provide

normalized values ranging from 0 to 1. The users can change the value range, for example, low or high,

if it is desirable.
6 Format used for documenting the IT service quality measures

The following information is given for each quality measure in the Tables 1 to 27:

a) ID: identification code of the quality measure. Each ID consists of the following two parts:

— abbreviated alphabetic code representing the quality characteristics as one capital X and sub-

characteristics as one capital X followed by lower-case x (for example, “UUe” denotes “User

error protection” measures for “Usability”);
— serial number in sequential order within quality sub-characteristic.
b) Name: quality measure name.
c) Description: the information provided by the quality measure.

d) Measurement function: mathematical formula showing how the quality measure elements are

combined to produce the quality measure.
7 IT service quality measures
7.1 General

The quality measures in this clause are listed by quality characteristics and sub-characteristics, in the

order used in ISO/IEC TS 25011; and the word “measures” in this clause means quality measures.

NOTE 1 The list of quality measures shown in Tables 1 is not final, and can be revised in future editions of this

document. Users of this document are invited to provide feedback.
Table 1 — IT service quality measures
Characteristics Sub-characteristics Measures
Functional coverage
Completeness Goals and objectives achievement
Data items populated
IT service function correctness
Correctness
Suitability Compliance of defined process
IT service function appropriateness for context of use
Appropriateness
IT service function appropriateness to service users
IT service consistency
Consistency
IT service process quality consistency
4 PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO/IEC TS 25025:2021(E)
Table 1 (continued)
Characteristics Sub-characteristics Measures
Description completeness
Appropriateness recogniza-
bility
Demonstration coverage
User guide completeness
Learnability User guide effectiveness
User guide efficiency
Message clarity
Understandable categorization of service
Usability Operability
IT service automation
Effort time estimability
Avoidance of user operation error
User error protection
User error correction
Accessibility for users with disabilities
Accessibility
Language supportability
Courtesy Courteous service language, behaviour and attitude
Access controllability
Completeness of access control methods to protect confi-
Confidentiality
dential information
Effectiveness of confidentiality protection
Security
Integrity Data integrity
User audit trail completeness
Traceability
Traceability completeness
Coverage of IT service contin
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.