EN ISO 9241-171:2008

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Ergonomie der Mensch-System-Interaktion - Teil 171: Leitlinien für die Zugänglichkeit von Software (ISO 9241-171:2008)Ergonomie de l'interaction homme-systeme - Partie 171: Lignes directrices relatives a l'accessibilité aux logiciels (ISO 9241-171:2008)Ergonomics of human-system interaction - Part 171: Guidance on software accessibility (ISO 9241-171:2008)35.180Terminalska in druga periferna oprema ITIT Terminal and other peripheral equipment13.180ErgonomijaErgonomicsICS:Ta slovenski standard je istoveten z:EN ISO 9241-171:2008SIST EN ISO 9241-171:2009en,fr,de01-april-2009SIST EN ISO 9241-171:2009SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN ISO 9241-171July 2008ICS 13.180 English VersionErgonomics of human-system interaction - Part 171: Guidanceon software accessibility (ISO 9241-171:2008)Ergonomie de l'interaction homme-système - Partie 171:Lignes directrices relatives à l'accessibilité aux logiciels(ISO 9241-171:2008)Ergonomie der Mensch-System-Interaktion - Teil 171:Leitlinien für die Zugänglichkeit von Software (ISO 9241-171:2008)This European Standard was approved by CEN on 28 June 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 9241-171:2008: ESIST EN ISO 9241-171:2009

Reference numberISO 9241-171:2008(E)© ISO 2008
INTERNATIONAL STANDARD ISO9241-171First edition2008-07-15Ergonomics of human-system interaction — Part 171: Guidance on software accessibility Ergonomie de l'interaction homme-système — Partie 171: Lignes directrices relatives à l'accessibilité aux logiciels
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ISO 9241-171:2008(E) © ISO 2008 – All rights reserved iiiContents Page Foreword.iv Introduction.vi 1 Scope.1 2 Normative references.1 3 Terms and definitions.2 4 Rationale and benefits of implementing accessibility.8 5 Principles for designing accessible software.8 6 Sources of variation in user characteristics.9 7 How to use this part of ISO 9241.10 7.1 General.10 7.2 Conformance.10 8 General guidelines and requirements.11 8.1 Names and labels for user-interface elements.11 8.2 User preference settings.14 8.3 Special considerations for accessibility adjustments.16 8.4 General control and operation guidelines.17 8.5 Compatibility with assistive technology.21 8.6 Closed systems.26 9 Inputs.26 9.1 Alternative input options.26 9.2 Keyboard focus.28 9.3 Keyboard input.29 9.4 Pointing devices.35 10 Outputs.39 10.1 General output guidelines.39 10.2 Visual output (displays).39 10.3 Text/fonts.40 10.4 Colour.41 10.5 Window appearance and behaviour.42 10.6 Audio output.45 10.7 Text equivalents of audio (captions).47 10.8 Media.47 10.9 Tactile output.48 11 On-line documentation, “Help” and support services.48 11.1 Documentation and “Help”.48 11.2 Support services.49 Annex A (informative)
Overview of the ISO 9241 series.51 Annex B (informative)
List of requirements.55 Annex C (informative)
Sample procedure for assessing applicability and conformance.57 Annex D (informative)
Activity limitation issues.68 Annex E (informative)
Access features.74 Annex F (informative)
Accessibility and usability.83 Bibliography.85 SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) iv © ISO 2008 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member 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 shall not be held responsible for identifying any or all such patent rights. ISO 9241-171 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4, Ergonomics of human-system interaction. This first edition of ISO 9241-171 cancels and replaces ISO/TS 16071:2003, of which it constitutes a technical revision. ISO 9241 consists of the following parts, under the general title Ergonomic requirements for office work with visual display terminals (VDTs): ⎯ Part 1: General introduction ⎯ Part 2: Guidance on task requirements ⎯ Part 3: Visual display requirements ⎯ Part 4: Keyboard requirements ⎯ Part 5: Workstation layout and postural requirements ⎯ Part 6: Guidance on the work environment ⎯ Part 7: Requirements for display with reflections ⎯ Part 8: Requirements for displayed colours ⎯ Part 9: Requirements for non-keyboard input devices ⎯ Part 11: Guidance on usability ⎯ Part 12: Presentation of information ⎯ Part 13: User guidance ⎯ Part 14: Menu dialogues ⎯ Part 15: Command dialogues SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved v⎯ Part 16: Direct manipulation dialogues ⎯ Part 17: Form filling dialogues Guidance on software individualization and human-centred design process for interactive systems are to form the subjects of future parts 129 and 210. ISO 9241 also consists of the following parts, under the general title Ergonomics of human-system interaction: ⎯ Part 20: Accessibility guidelines for information/communication technology (ICT) equipment and services ⎯ Part 110: Dialogue principles ⎯ Part 151: Guidance on World Wide Web user interfaces ⎯ Part 171: Guidance on software accessibility ⎯ Part 300: Introduction to electronic visual display requirements ⎯ Part 302: Terminology for electronic visual displays ⎯ Part 303: Requirements for electronic visual displays ⎯ Part 304: User performance test methods ⎯ Part 305: Optical laboratory test methods for electronic visual displays ⎯ Part 306: Field assessment methods for electronic visual displays ⎯ Part 307: Analysis and compliance test methods for electronic visual displays
⎯ Part 308: Surface-conduction electron-emitter displays (SED) [Technical Report] ⎯ Part 309: Organic light-emitting diode (OLED) displays [Technical Report] ⎯ Part 400: Principles and requirements for physical input devices ⎯ Part 410: Design criteria for physical input devices ⎯ Part 920: Guidance on tactile and haptic interactions Framework for tactile and haptic interaction is to form the subject of a future part 910. SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) vi © ISO 2008 – All rights reserved Introduction The purpose of this part of ISO 9241 is to provide guidance on the design of the software of interactive systems so that those systems achieve as high a level of accessibility as possible. Designing human-system interactions to increase accessibility promotes increased effectiveness, efficiency and satisfaction for people having a wide variety of capabilities and preferences. Accessibility is therefore strongly related to the concept of usability (see ISO 9241-11). The most important approaches to increasing the accessibility of a human-system interface are ⎯ adopting a human-centred approach to design (see ISO 13407), ⎯ following a context-based design process, ⎯ providing the capacity for individualization (see ISO 9241-110), and ⎯ offering individualized user instruction and training. It is important to incorporate accessibility goals and features into the design as early as possible, when it is relatively inexpensive compared to the cost of modifying products to make them accessible once they have been designed. As well as providing guidance for achieving that, this part of ISO 9241 addresses the increasing need to consider social and legislative demands for ensuring accessibility by the removal of barriers that prevent people from participating in life activities such as the use of environments, services, products and information. This part of ISO 9241 is applicable to software that forms part of interactive systems used in the home, in leisure activities, in public situations and at work. Requirements and/or recommendations are provided for system design, appearance and behaviour, as well as specific accessibility issues, thereby complementing International Standards ISO 9241-11, ISO 9241-12, ISO 9241-13, ISO 9241-14, ISO 9241-15, ISO 9241-16 and ISO 9241-17, ISO 9241-110 and ISO 14915, as well as reflecting the goals outlined in ISO Guide 71 [60]. Conforming with the aforementioned International Standard is also important if the goal of accessibility is to be achieved. NOTE 1 While the requirements and recommendations of this part of ISO 9241 are generally applicable to all software application domains, additional detailed guidance on the accessibility of Web content (including Web applications) is available from the Web Content Accessibility Guidelines (WCAG) [53]. This part of ISO 9241 is based on the current understanding of the characteristics of individuals who have particular physical, sensory and/or cognitive impairments. However, accessibility is an issue that affects many groups of people. The intended users of interactive systems are consumers or professionals — people at home, at school, engineers, clerks, salespersons, Web designers, etc. The individuals in such target groups vary significantly as regards physical, sensory and cognitive abilities and each target group will include people with different abilities. Thus, people with disabilities do not form a specific group that can be separated out and then disregarded. The differences in capabilities can arise from a variety of factors that serve to limit the capability to engage in the activities of daily living, and are a “universal human experience” [50]. Therefore, accessibility addresses a widely defined group of users including ⎯ people with physical, sensory and cognitive impairments present at birth or acquired during life, ⎯ elderly people who can benefit from new products and services but who experience reduced physical, sensory and cognitive capacities, ⎯ people with temporary disabilities, such as a person with a broken arm or someone who has forgotten his/her glasses, and ⎯ people who experience difficulties in particular situations, such as a person who works in a noisy environment or has both hands occupied by other activities. SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved viiWhen designing and evaluating interactive systems there are other terms that are often associated with accessibility. In Europe, the expression design for all or, in North America, universal design [9], address the goal of enabling maximum access to the maximum number and diversity of users, irrespective of their skill level, language, culture, environment or disability. This does not mean that every product will be usable by every consumer. There will always be a minority of people with severe or multiple disabilities who will need adaptations or specialized products. Accessibility as defined in this part of ISO 9241 emphasizes the goals of maximizing the number of users and striving to increase the level of usability that these users experience. This part of ISO 9241 recognizes that some users of software will need assistive technologies in order to use a system. In the concept of designing software to be accessible, this includes the capability of a system to provide connections to, and enable successful integration with, assistive technologies, in order to increase the number of people who will be able to use the interactive system. Guidance is provided on designing software that integrates as effectively as possible with common assistive technologies. It is important to note that accessibility can be provided by a combination of both software and hardware controlled by software. Assistive technologies typically provide specialized input and output capabilities not provided by the system. Software examples include on-screen keyboards that replace physical keyboards, screen-magnification software that allows users to view their screens at various levels of magnification, and screen-reading software that allows blind users to navigate through applications, determine the state of controls, and read text via text-to-speech conversion. Hardware examples include head-mounted pointing devices instead of mice and Braille output devices instead of a video display. There are many others. When users employ add-on assistive software and/or hardware, usability is enhanced to the extent that systems and applications integrate with those technologies. For this reason, platforms (including operating systems) must provide programming services to allow software to operate effectively with add-on assistive software and hardware as specified in this part of ISO 9241. If systems do not provide support for assistive technologies, the probability increases that users will encounter problems with compatibility, performance and usability. This part of ISO 9241 serves the following types of users: ⎯ designers of user-interface development tools and style guides to be used by interface designers; ⎯ user-interface designers, who will apply the guidance during the development process; ⎯ developers, who will apply the guidance during the design and implementation of system functionality; ⎯ those responsible for implementing solutions to meet end-user needs; ⎯ buyers, who will reference this part of ISO 9241 during product procurement; ⎯ evaluators, who are responsible for ensuring that products are in accordance with this part of ISO 9241. NOTE 2 In this document the term “developers” is used as shorthand for all those involved in the development of software design and creation, which sometimes can span different collaborating or contracting organizations. The ultimate beneficiary of this part of ISO 9241 will be the end-user of the software. Although it is unlikely that end-users will read this part of ISO 9241, its application by designers, developers, buyers and evaluators ought to provide user interfaces that are more accessible. This part of ISO 9241 concerns the development of software for user interfaces. However, those involved in designing the hardware aspects of user interfaces may also find it useful when considering the interactions between software and hardware aspects. ISO 9241 was originally developed as a seventeen-part International Standard on the ergonomics requirements for office work with visual display terminals. As part of the standards review process, a major restructuring of ISO 9241 was agreed to broaden its scope, to incorporate other relevant standards and to make it more usable. The general title of the revised ISO 9241, “Ergonomics of human-system interaction”, reflects these changes and aligns the standard with the overall title and scope of Technical Committee ISO/TC 159, SC 4. The revised multipart standard is structured as series of standards numbered in the “hundreds”: the 100 series deals with software interfaces, the 200 series with human-centred design, the 300 series with visual displays, the 400 series with physical input devices, and so on. See Annex A for an overview of the entire ISO 9241 series.
INTERNATIONAL STANDARD ISO 9241-171:2008(E) © ISO 2008 – All rights reserved 1Ergonomics of human-system interaction — Part 171: Guidance on software accessibility 1 Scope This part of ISO 9241 provides ergonomics guidance and specifications for the design of accessible software for use at work, in the home, in education and in public places. It covers issues associated with designing accessible software for people with the widest range of physical, sensory and cognitive abilities, including those who are temporarily disabled, and the elderly. It addresses software considerations for accessibility that complement general design for usability as addressed by ISO 9241-110, ISO 9241-11 to ISO 9241-17, ISO 14915 and ISO 13407. This part of ISO 9241 is applicable to the accessibility of interactive systems. It addresses a wide range of software (e.g. office, Web, learning support and library systems). It promotes the increased usability of systems for a wider range of users. While it does not cover the behaviour of, or requirements for, assistive technologies (including assistive software), it does address the use of assistive technologies as an integrated component of interactive systems. It is intended for use by those responsible for the specification, design, development, evaluation and procurement of software platforms and software applications. 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 9241-11:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 11: Guidance on usability ISO 9241-12:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 12: Presentation of information ISO 9241-13:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 13: User guidance ISO 9241-14:1997, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 14: Menu dialogues ISO 9241-15:1997, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 15: Command dialogues ISO 9241-16:1999, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 16: Direct manipulation dialogues ISO 9241-17:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 17: Form filling dialogues SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) 2 © ISO 2008 – All rights reserved ISO 9241-110:2006, Ergonomics of human-system interaction — Part 110: Dialogue principles ISO 13407:1999, Human-centred design processes for interactive systems ISO 14915 (all parts), Software ergonomics for multimedia user interfaces 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 accelerator keys shortcut keys key combinations which invoke a menu option without displaying the menu on which the option appears or intermediate menus [ISO 9241-14:1997] 3.2 accessibility 〈interactive system〉 usability of a product, service, environment or facility by people with the widest range of capabilities NOTE 1 The concept of accessibility addresses the full range of user capabilities and is not limited to users who are formally recognized as having a disability. NOTE 2 The usability-orientated concept of accessibility aims to achieve levels of effectiveness, efficiency and satisfaction that are as high as possible considering the specified context of use, while paying particular attention to the full range of capabilities within the user population. 3.3 accessibility feature feature (etc.) that is specifically designed to increase the usability of products for those experiencing disabilities 3.4 activation internal state with differential degrees of mental and physical functional efficiency [ISO 10075:1991] 3.5 assistive technology AT hardware or software added to, or incorporated within, a system that increases accessibility for an individual EXAMPLE Braille display, screen reader, screen magnification software, eye tracking devices. 3.6 chorded key-press keyboard key or pointing-device button presses where more than one button is held down simultaneously to invoke an action NOTE This includes both uses of modifier keys with other (non-modifier) keys as well as use of multiple non-modifier keys to enter data or invoke an action. 3.7 closed system system that does not allow user connection or installation of assistive technology that would have programmatic access to the full user interface SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved 3NOTE This can be because of policy, system architecture, physical constraints or for any number of other reasons. 3.8 colour scheme set of colour assignments used for rendering user-interface elements NOTE “Colour” refers to a combination of hue, saturation, and brightness. 3.9 contrast 〈perceptual sense〉 assessment of the difference in appearance of two or more parts of a field seen simultaneously or successively (hence: brightness contrast, lightness contrast, colour contrast, etc.) [CIE 17.4:1987, definition 845-02-47] 3.10 cursor visual indication of where the user interaction via keyboard (or keyboard emulator) will occur cf. keyboard focus cursor (3.22), text cursor (3.35), pointer (3.30) 3.11 effectiveness accuracy and completeness with which users achieve specified goals [ISO 9241-11:1998, 3.2] 3.12 efficiency resources expended in relation to the accuracy and completeness with which users achieve goals [ISO 9241-11:1998, 3.3] 3.13 explicit designator code or abbreviation for a menu option or control label, set apart from the name (usually to the left of it), and typed in for selection cf. implicit designator ( 3.16) EXAMPLE “O”, “C”, “S”, “P”, as shown in the menu in Figure 1. O Open C Close S Save P Print Figure 1 — Examples of explicit designators SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) 4 © ISO 2008 – All rights reserved 3.14 focus cursor location cursor indicator showing which user-interface element has keyboard focus cf. input focus ( 3.18) and cursor (3.10). EXAMPLE Box or highlighted area around a text field, button, list or menu option. NOTE The appearance of this indicator usually depends on the kind of user-interface element that has focus. The user-interface element with focus can be activated if it is a control (e.g. button, menu item) or selected if it is a selectable user-interface element (e.g. icon, list item). 3.15 icon graphic displayed on the screen of a visual display that represents a function of the computer system [ISO/IEC 11581-1:2000, 4.7] 3.16 implicit designator portion of an option name or control label used for keyboard selection EXAMPLE “P” on a screen used for initiating a print job where the control label is displayed as “Print”. 3.17 individualization modification of interaction and presentation of information to suit individual capabilities and needs of users 3.18 input focus in relation to a given input device, the indication of the object upon which the user directs input [ISO 9241-16:1999] EXAMPLE Pointer focus and keyboard focus are input foci. 3.19 keyboard emulator software or hardware that generates input identical to that from a keyboard NOTE A keyboard emulator can provide a representation of keys (e.g. on-screen keyboard) or not (e.g. voice recognition). EXAMPLE Platform-based on-screen keyboards, speech input, handwriting, wherever their output appears to applications as keystroke input. 3.20 keyboard equivalent key or key combination that provides access to a function usually activated by a pointing device, voice input or other input or control mechanism 3.21 keyboard focus current assignment of the input from the keyboard or equivalent to a user-interface element NOTE For an individual user-interface element, focus is indicated by a focus cursor. 3.22 keyboard focus cursor visual indication of where the user interaction via keyboard (or keyboard emulator) will occur cf. keyboard focus (3.21), pointer (3.30), text cursor (3.35). SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved 53.23 label short descriptive title for an entry or read-only field, table, control or object cf. name (3.27) EXAMPLE 1 Heading, prompt for entry field, text or graphic that accompanies and identifies a control (such as those displayed on the face of buttons), audible prompt used by an interactive voice response system. EXAMPLE 2 “Creation Time”, as shown in Figure 2.
Figure 2 — Example of text field with label EXAMPLE 3 “Pagination”, “Widow/Orphan control”, “Keep with text”, “Keep lines together”, “Page break before”, as shown in Figure 3.
Figure 3 — Example of check box group with labels for group and each check box EXAMPLE 4 Image of a printer in a window that the user can click to print the current document. NOTE 1 In some applications, labels are classified as protected fields.
NOTE 2 Adapted from ISO 9241-17:1998, definition 3.4. NOTE 3 For the purposes of this part of ISO 9241, label refers to the presented title for a user-interface element — in contrast with the name attribute, which might or might not be presented to users but is available to assistive technologies. Textual labels are often a visual display of the name. 3.24 latch mode in which any modifier key remains logically pressed (active) in combination with a single subsequent non-modifier key-press or pointing-device button action cf. lock (3.25) 3.25 lock persistent mode in which one or more modifier keys or pointing-device buttons remain logically pressed (active) until lock mode for the key or button is turned off cf. latch (3.24) NOTE 1 Unlike latch, which affects only keyboard and pointing device actions, lock will affect any software that uses the modifier key(s) to alter its behaviour. SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) 6 © ISO 2008 – All rights reserved NOTE 2 Lock mode is usually turned off explicitly by the user, but can also be turned off at other times such as at system shutdown or restart. 3.26 modifier key keyboard key that changes the action or effect of another key or a pointing device EXAMPLE 1 Moving the keyboard focus with the shift key held down, thereby extending the current selection in the direction of cursor movement rather than merely moving the position of the cursor. EXAMPLE 2 Pressing “C”, to obtain the input of that character, pressing “Ctrl+C” to obtain the “Copy” function. 3.27 name word or phrase associated with a user-interface element and that is used to identify the element to the user cf. label (3.23). NOTE 1 Names are most useful when they are the primary word or phrase by which the on-screen instructions, software documentation and the user refer to the element, and when they do not contain the type or status of the user-interface element. NOTE 2 The name attribute might or might not be presented to users but is available to assistive technologies — in contrast with label. For the purposes of this part of ISO 9241, label refers to the presented title for a user-interface element. Textual labels are often a visual display of the name. NOTE 3 When a textual label is provided it would generally present the name or a shortened version of the name. Not all user-interface elements have labels, however. In those cases, the names would be available to assistive technologies (or sometimes by pop-up tool tips, etc.). NOTE 4 Names are not to be confused with internal identifiers (ID), which can be used by software and might not be designed to be understood by a human. 3.28 natural language language that is, or that was, in active use in a community of people, the rules of which are mainly deduced from the usage 3.29 platform software software that interacts with hardware or provides services for other software EXAMPLE Operating system, device driver, windowing system, software toolkit. NOTE 1 A browser can function both as an application and as platform software. NOTE 2 For the purposes of this part of ISO 9241, software refers to both platform software and application software. 3.30 pointer graphical symbol that is moved on the screen according to operations with a pointing device NOTE Users can interact with elements displayed on the screen by moving the pointer to that location and starting a direct manipulation. [ISO 9241-16:1999, 3.15] 3.31 pointer focus current assignment of the input from the pointing device to a window NOTE The window with pointer focus usually has some distinguishing characteristic, such as a highlighted border and/or title bar. SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved 73.32 pointing device device that translates a human controlling operation to a controlling operation on the display NOTE 1 Depending on the applied technology, not only machine devices but also parts of the human body (e.g. fingers, arms) can currently be used as pointing devices. [ISO 9241-16:1999] NOTE 2 Pointing devices typically have buttons that are used to activate or manipulate user-interface elements. NOTE 3 Almost any hardware can be used to control a pointer (3.30) with the appropriate software. 3.33 satisfaction freedom from discomfort, and positive attitudes towards the use of the product [ISO 9241-11:1998, 3.4] 3.34 screen reader assistive technology that allows users to operate software without the need to view the visual display NOTE 1 Output of screen readers is typically text-to-speech or dynamic Braille output on a refreshable Braille display. NOTE 2 Screen readers rely on the availability of information from the operating system and applications, such as the name or label of the user-interface element. 3.35 text cursor visual indication of the current insertion point for text entry cf. pointer (3.30), focus cursor (3.14). 3.36 usability extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use [ISO 9241-11:1998, 3.1] 3.37 user interface UI all components of an interactive system (software or hardware) that provide information and controls for the user to accomplish specific tasks with the interactive system [ISO 9241-110:2006, 3.9] 3.38 user-interface element user-interface object entity of the user interface that is presented to the user by the software EXAMPLE Text, graphic, control. NOTE 1 User-interface elements can be interactive or not. NOTE 2 Both entities relevant to the task and entities of the user interface are regarded as user-interface elements. A user-interface element can be a visual representation or an interaction mechanism for a task object (such as a letter, sales order, electronic part or wiring diagram) or a system object (such as a printer, hard disk or network connection). It can be possible for the user to directly manipulate some of these user-interface elements. NOTE 3 User-interface elements in a graphical user interface include such things as basic objects (such as window title bars, menu items, push buttons, image maps, and editable text fields) or containers (such as windows, grouping SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) 8 © ISO 2008 – All rights reserved boxes, menu bars, menus, groups of mutually-exclusive option buttons, and compound images that are made up of several smaller images). User-interface elements in an audio user interface include such things as menus, menu items, messages, and action prompts. 4 Rationale and benefits of implementing accessibility Accessibility is an important consideration in the design of products, systems, environments and facilities because it affects the range of people who are able to use them and use them easily. The more accessible a design, the wider the range of people who will find it usable. Accessibility can be improved by incorporating features and attributes known to benefit users with special requirements. To determine the achieved level of accessibility, it is necessary to measure the effectiveness, efficiency and satisfaction of users working with a product or interacting with an environment for the widest range of users. Measurement of accessibility is particularly important in view of the complexity of the interactions with the user, the goals, the task characteristics and the other elements of the context of use. A product, system, environment or facility can have significantly different levels of accessibility when used in different contexts. Planning for accessibility as an integral part of the design and development process involves the systematic identification of requirements for accessibility, including accessibility measurements and verification criteria within the context of use. These provide design targets that can form the basis for verification of the resulting design. The approach adopted in this part of ISO 9241 has the following benefits: ⎯ the framework can be used to identify the aspects of accessibility and the components of the context of use to be taken into account when specifying, designing or evaluating the accessibility of a product; ⎯ the performance and satisfaction of the users can be used to measure the extent to which a product, system, environment or facility is accessible in a specific context; ⎯ measures of the performance and satisfaction of the users can provide a basis for determining and comparing the accessibility of products having different technical characteristics, which are used in the same context; ⎯ the accessibility planned for a product can be defined, documented and verified (e.g. as part of a quality plan). 5 Principles for designing accessible software There are different ways of designing accessible software. This part of ISO 9241 does not assume any one specific design method or process, nor does it cover all the different activities necessary to ensure accessible system design. It is complementary to existing design methods and provides a human-centred accessibility perspective, based on ISO 13407, that can be applied — whatever the specific design process or particular context of use — to increase the number of people who are able to use the software. The guidance provided in this part of ISO 9241 is applicable at any stage in the development of an interactive system. Designing accessible software should adhere to the following principles. ⎯ Equitable use Equitable solutions provide the same means of use for all users: identical whenever possible; equivalent when not. Achieving equitable use will ensure that solutions designed to increase accessibility do not result in such things as loss of privacy, increased risks to personal safety or security, or the stigmatization of individuals. SIST EN ISO 9241-171:2009

ISO 9241-171:2008(E) © ISO 2008 – All rights reserved 9⎯ Suitability for the widest range of use Suitability for the widest range of use involves designing with the objective of producing solutions that will be useful, acceptable and available to the widest range of users within the intended user population, taking account of their special abilities, variations in their capabilities, the diversity of their tasks, and their differing environmental, economic and social circumstances. ⎯ Robustness (WCAG 2.0 Principle No. 4) [53] Software should be designed to be as robust as possible to allow it to work with current and future assistive technologies. Although it is not feasible to make all software accessible without add-on assistive technologies, these guidelines should help designers develop software that increases accessibility without the use of assistive technologies, and, by providing the necessary interface information, enables assistive software and devices to operate effectively and efficiently when used. The software can promote integration of assistive t
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