THE FUTURE LOOKS BRIGHT:
INTERNATIONAL STANDARDS FOR ACCESSIBLE SOFTWARE
Presenter #1 Go to previous article
David
Fourney
University of Saskatchewan
176 Thorvaldson Building, 110 Science Place
Saskatoon
Saskatchewan
S7N 5C9
Canada
Day Phone: +1-306-978-3943
Fax:
Email: david.fourney@usask.ca
Recent work in International Standards has led to the development of
three standards on software accessibility: ISO 9241-20, ISO 9241-171, and ISO/IEC
24756. We discuss the benefits provided by these standards, outline their
content, and encourage their use.
David Fourney, Department of Computer Science,
University of Saskatchewan, Saskatoon, Saskatchewan, Canada
david.fourney@usask.ca
Jim Carter, Department of Computer Science, University of Saskatchewan,
Saskatoon, Saskatchewan, Canada carter@cs.usask.ca
Abstract:
Recent work in International Standards has led to the development of three
standards on software accessibility: ISO 9241-20, ISO 9241-171, and ISO/IEC
24756. This paper discusses the benefits provided by these standards and
encourages their use.
1. Introduction:
International Standards play an important role in global commerce.
They form an agreement that ensures a common practice is followed.
Although several organizations are involved in international standards
development, the International Organisation for Standardisation (ISO) is probably the most well-known.
In some countries international standards are voluntary,
in others they carry the strength of law. Some international standards,
such as the ISO 9000 series, have received a great amount of attention and are,
on some level, at least recognizable by the general public whether they know
what it is or not. Other international standards, such as ISO/IEC 10918-1
(i.e., the document that sets out the graphic format known as "JPEG"
frequently used in web pages for still pictures) (ISO, 1994), are used by many
without realizing it.
The upcoming publication of ISO 9241-20, ISO 9241-171, and ISO/IEC 24756
provide a major achievement in the evolution of accessible software design
towards the day when it is fully assimilated and routinely considered a part of
all software development.
2. ISO 9241-171 Guidance on Software Accessibility
The Human Factors and Ergonomics
Society's HFES/ANSI 200 committee recognized the importance of developing
accessibility standards and started work in this area in the mid 1990's. While
their original draft was based on the Nordic Accessibility Guidelines (Thoren, 1998) they have gone far beyond the original set of
guidelines. In 1998 the HFES/ANSI 200 committee submitted their work to date to
ISO committee TC159/SC4/WG5 Software Ergonomics and Human Computer Dialogue as
the basis for international work on software accessibility standardization.
This led to the development and publication of ISO TS 16071 Guidance on
accessibility for human computer interfaces.
International standards are typically based on empirical research, accepted
best practice, or both. Often, standards developed by one country are
offered as a source for an international standard. This is true of ISO
9241-171, which is based on the American HFES/ANSI 200.2 and their predecessor
document ISO TS 16071.
The ISO 9241 series is a set of standards concerned with the ergonomics of
computer software. Part 171 is especially concerned with the
accessibility of software. An evaluation of the content of ISO TS 16071 soon
after its publication suggested a number of key areas that needed further
attention (Carter and Fourney, 2004). Whereas ISO TS
16071 focused on providing accessibility to people with special needs, ISO
9141-171 takes a wider "design for all" approach. The current version
of ISO 9241-171 contains individual guidelines as well as guidance on complying
with these guidelines.
ISO 9241-171 contains a variety of new content beyond that found in
previous versions. For example, ISO 9241-171 defines accessibility as
the, "usability of a product, service, environment, or facility by people
with the widest range of capabilities". Many authors believe that there
should be no distinction between the concepts of usability and accessibility
(e.g., according to Moulton, Huyler, Hertz, & Levenson, 2002, "Accessibility is good
usability."), and that the term "usability" should encompass the
meaning of both terms. The ISO definition of the term
"accessibility" recognizes that usability problems impact all users
equally, regardless of ability and that a person with a disability is not
disadvantaged to a greater extent by usability issues than a person without a
disability (Thatcher et al., 2002).
This ISO definition also recognizes that accessibility cannot be seen as a
"special case" of usability. The notion that if usability is
about producing products and systems that are easy to use and perform the
function for which they were designed, then accessible design is about
producing products and systems that are usable by all persons regardless of (dis)ability is dangerous. The danger here is that a
product could be "usable" without being "accessible."
That is, a designer could view accessible design as "outside
of" usable design and design an inaccessible product.
3. ISO 9241-20 Accessibility guidelines for information communication
equipment and services
With the explicit focus of ISO 9241-171
on software accessibility, the need was recognized for a computer hardware
accessibility standard. However, in advance to developing a specific hardware
standard, the ISO committee on Ergonomics of Human-system Interaction (ISO
TC159/SC4) decided to develop a high level systems and services standard (ISO
9241-20) that would apply to both hardware and software, without duplicating
any of the content that is contained in ISO 9241-171 or that would be contained
in a hardware accessibility standard.
ISO 9241-20 recognizes that accessibility is achieved and improved by
serving "the widest variations within a context of use" which can be
based on user characteristics, equipment characteristics, environmental
characteristics, and task characteristics, and their variability. It presents a
framework for accessibility that considers the characteristics and needs of
users, tasks, equipment, and the environment and presents guidance relating to
each of these four types of characteristics. It also presents 18 user-related,
15 equipment-related, 6 task-related, and 3 environment-related guidelines.
4. ISO/IEC 24756 Algorithmic framework for determining accessibility for
individual users of interactive systems
As noted above, international standards
are typically based on empirical research, accepted best practice, or both.
ISO/IEC 24756, "Algorithmic framework for determining accessibility
for individual users of interactive systems" (ISO & IEC, 2005) is a
standard that identifies "inaccessibilities".
It is based on the definition of accessibility used in ISO 9241-171 and the
model proposed by Carter and Fourney (2004). ISO/IEC
24756 compares the needs and abilities of systems with users to communicate
using various modalities and takes into account the environment(s) in which the
user and system interact. It allows the consideration of multiple levels of
system components, including: application software, operating systems, computer
hardware, peripheral devices, and assistive technologies. This standard can be
used to analyze existing human-computer interactions and to help evaluate the
usefulness of proposed assistive technologies.
5. Conclusion
The upcoming publication of these standards is exciting. They will
each provide guidance to assist developers to design their products to meet the
needs of the widest number of users. This has implications for both
developers who will be able to sell their products to a wider audience, and
consumers with disabilities who will benefit from greater choice of products
accessible to them.
References
Carter, J., & Fourney, D. (2004).
Using a Universal Access Reference Model to identify further
guidance that belongs in ISO 16071. Universal Access in the Information
Society, 3 (1), 17-29. http://www.springerlink.com/link. asp?id=wdqpdu5pj0kb4q6b
International Organization for Standardization. (2002). ISO/TS 16071:2002
Ergonomics of human system interaction - Guidance on accessibility for human
computer interfaces.
International Organization for Standardization, &
International Electrotechnical Commission.
(2005). ISO/IEC CD 24756 Information technology - Algorithmic
framework for determining accessibility for individual users of interactive
systems (ISO/IEC JTC 1 / SC35 Document N903).
International Organization for Standardization, &
International Electrotechnical Commission.
(1994). ISO/IEC 10918-1:1994 Information technology - Digital compression and
coding of continuous-tone still images: Requirements and guidelines.
Moulton, G., Huyler, L., Hertz,
J., & Levenson, M. (2002).
Accessible technology in today's business: Case studies for success.
Thatcher, J., Waddell, C., Henry, S., Swierenga,
S., Urban, M., Burks, M., Regan, B., & Bohman, P.
(2002). Constructing accessibile
web sites.
Thoren, C. (ed.) (1998). Nordic Guidelines for Computer Accessibility (Second Edition).
Nordic Cooperation on Disability. http://trace.wisc.edu/docs/nordic_guidelines/nordic_guidelines.htm
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