Biomedical Engineering Reference
In-Depth Information
2. Accessibility as access to information and communication technology: The Web
Accessibility Initiative (WAI) defines accessibility as allowing people with dis-
abilities to “perceive, understand, navigate and interact with the web” (2006).
3. Accessibility as access to a usable interface: ISO 9241-171 defines accessibility
as the “usability of a product, service, environment, or facility by people with
the widest range of capabilities” (ISO 2008).
• Soniication: This is a process of “transformation of data relations into perceived
relations in an acoustic signal for the purposes of facilitating communication or
interpretation” (Kramer et al. 1997, p. 3).
• Usability: This is the extent to which a product can be used by speciied users to
achieve specified goals with effectiveness, efficiency, and satisfaction in a speci-
fied context of use (ISO 1998).
• Effectiveness
is the accuracy and completeness with which users achieve speci-
fied goals;
• Eficiency
is the resources expended in relation to the accuracy and complete-
ness with which users achieve goals; and
• Satisfaction
is the freedom from discomfort and positive attitudes toward the
use of the product when users achieve goals.
In medicine and rehabilitation, a further distinction is made between efficacy and effec-
tiveness
as follows (Haynes 1999; Marley 2000):
• Eficacy
refers to the accuracy and completeness with which users achieve spe-
cific goals under controlled or ideal conditions
(e.g., within a clinic or rehabili-
tation setting).
• Effectiveness
refers to the accuracy and completeness with which users achieve
specific goals under real-world conditions.
• Universal Design or Design for All (UD):
In the context of human-computer inter-
action, this implies a proactive approach toward products and environments that
can be accessible and usable by the broadest possible end-user population, with-
out the need for additional adaptations or specialized (re-)design. This approach
refers to “the conscious effort to consider and take account of the widest possible
range of end user requirements throughout the development life-cycle of products
or services” (Akoumianakis and Stephanidis 2001).
• User-Centered Design (UCD):
This term was first originated in Donald Norman's
research laboratory at the University of California in the 1980s (Norman and Draper
1986). UCD is a design process characterized by a cycle of tests and re-tests of the
technology. In the first series of tests run to optimize the interface, experts analyze
how subjects are likely to use the prototype of the interface; in this first step, experts
try to simulate the behavior of a common user following the guidelines of a user's
model. Then, in the second series of tests, users are involved in a prototype analysis
to further identify interface problems and to allow a redesign of the information
architecture. Following the results of these two different cycles of tests (one per-
formed by experts and one by users), the UCD model is able to take into account
the needs and abilities of people and, therefore, is also able to optimize the interface
according to these same needs and abilities, rather than forcing users to adapt them-
selves to an interface that is strictly dependent on the developer's model.
