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Designing User Interfaces for All

Constantine Stephanidis
Institute of Computer Science
Foundation for Research and Technology
Hellas Science and Technology Park of Crete
Heraklion, Crete
GR-71110 Greece
Tel: +30-81-391741
Fax: +30-81-391740
E-mail: cs@ics.forth.gr
  URL: www.ics.forth.gr/proj/at-hci


The emergence of the information society creates numerous new opportunities and challenges for disabled and elderly people. In this information era, it is increasingly important to ensure universal access and quality in use to the emerging interactive applications and telematic services for the population at large, taking proactively into account the requirements of people with disabilities. This paper advocates that the adoption of the design for all principle in the development life-cycle necessarily entails proactive measures. To this end, the paper reviews recent efforts and experiences towards user interfaces for all, a concept introduced to serve the goal of design for all in Human-Computer Interaction (HCI), and outlines the unified user interface development method for constructing user interfaces adaptable to the individual abilities, skills, requirements and preferences of the end user. The paper also refers to recent international efforts in the direction of realising an Information Society acceptable to all citizens.

1. Introducing Design for All in HCI

Until recently, the provision of accessibility to computer-based applications and services by disabled and elderly people has been mainly based on adaptations to existing systems, or on "dedicated" developments focusing on specific solutions, or targeted to a particular user category [12]. The rapid evolution of technology, however, restricts considerably the scope of such reactive approaches, since, progressively, they become technically more difficult and certainly less cost-effective, and they lead to solutions for people with disabilities which lag behind mainstream developments at least one technological generation [13]. An alternative approach to overcoming these limitations would be to cater for diverse user abilities, skills, requirements and preferences during the early design and development phases. It is in this context, that the concept of user interfaces for all has been proposed [12, 13], as a proactive realisation of the design for all principle, in order to ensure universal access and quality in use for all users, i.e. including disabled and elderly people.

Our contextual definition of design for all is different from other definitions which have recently appeared in the international literature, e.g. [8, 20], in that we restrict it to the field of HCI, and that we explicitly refer only to proactive approaches and measures. More specifically, design for all (or universal design, the terms are used interchangeably) refers to the conscious and systematic effort to proactively apply principles, methods and tools, in order to develop user interfaces for IT&T products and services which ensure universal access and quality in use to all users, thus avoiding the need for a posteriori adaptations or specialised design. The rationale behind universal design is grounded on the claim that designing for the "typical" or "average" user, as the case has been with "conventional" design of IT&T products, leads to user interfaces of products which do not cater for the needs of the broadest possible population, thus excluding various categories of users (e.g. non-expert IT users, the very young and elderly people, people with disabilities). Contrasting this view, the normative perspective of our contextual definition of universal design is that there is no "average" user and, consequently, design should be targeted towards all potential users.

In the context of the emerging Information Society, universal access signifies the right of all citizens to obtain equitable access to, and maintain effective interaction with, a community-wide pool of information resources and artefacts [16]. Universal access implies more than direct access or access through add-on (assistive) technologies [19], since it emphasises the principle that accessibility should be a design concern, as opposed to an afterthought. In other words, it is claimed that universal access entails proactive measures (i.e. methods, techniques, utilisation of appropriate tools, etc) for the development of interactive products and services which can be used effectively, efficiently and enjoyably by all users.

The notion of quality, on the other hand, has various meanings and connotations [3], and there are also different approaches to achieving product quality as part of the production process. In particular, quality in use is the high level design objective for a system to meet the real world needs of its intended users [4, 7], and entails the consideration of a broad range of functional and non-functional attributes, which characterise the use of information artefacts by humans, in their various problem-solving, information seeking and communication-intensive computer-mediated activities. This notion of quality goes beyond the "traditional" concept of usability (e.g. ease of use, learnability), to include aspects (such as usefulness, suitability for the task, tailorability, etc) which are not easily measurable by current approaches based on performance criteria, such as effectiveness, efficiency, satisfaction, etc.

2. Recent Efforts and Achievements

The vision of universal design has underpinned recent work by researchers in the fields of HCI and Assistive Technology. The main results today vary in context, scope and applicability across application domains. Nevertheless, they constitute a useful repository of experience and best practice that can influence future developments.

Recent advances towards universal design in HCI have provided a design wisdom in the form of universal design principles, general guidelines, platform specific accessibility guidelines (e.g. for GUIs or the Web), or domain-specific guidelines (e.g. for text editing, graphic manipulation). The systematic collection, consolidation and interpretation of these guidelines is currently pursued in the context of international collaborative initiatives (e.g. W3C-WAI, ISO TC 159 / WG 5 / SC 4). In recent years, several technical research and development projects have provided insights towards new user interface development frameworks and architectures that account (explicitly or implicitly) for several issues related to accessibility and interaction quality. Examples include the European Commission funded projects TIDE ACCESS, ACTS AVANTI and COST 219, as well as the Japanese FRIEND21 initiative.

Issues pertaining to design for all in HCI are also addressed: by the research community in the context of the Working Group on "User Interfaces for All" of the European Research Consortium for Informatics and Mathematics - ERCIM (http://www.ics.forth.gr/ercim-wg-ui4all); by industrial consortia, e.g. Roundtable in USA; by scientific and technical committees, e.g. the ACM public policy committee USACM; by national legislation, e.g., in the USA, the 1993 Americans with Disability Act, and the 1996 Telecommunications Act; by the United Nations General Assembly Standard Rules of 1995, etc.

More recently, international experts from large industrial organisations, high technology SMEs, international consortia, as well as academic and research organisations, have met in San Francisco, California, USA, on 29 August 1997, in the context of the Human-Computer Interaction International '97 Conference, and produced, in the context of a roundtable discussion, a White Paper entitled "Towards an Information Society for All: An International R&D Agenda" [16]. This White Paper proposes a short-, medium- and long-term international R&D agenda, based on the principle of designing for all users, and addresses technological- and user-oriented issues, critical application domains and support measures, which are necessary for the establishment of a favourable environment for the creation of an Information Society acceptable to all citizens.

3. User Interfaces for All and Unified User Interface Development

In the area of user interface software and technology, there are few concrete proactive approaches realising the design for all principle in HCI. One notable exception is the EC-funded TIDE TP1001 ACCESS project, which has proposed, designed and implemented the Unified User Interface Development Environment, as the vehicle to serve the goal of user interfaces for all. This development environment comprises methodologies and tools for the construction of user interfaces which are platform- and user-profile independent, and can be adapted to the individual end user abilities, skills, requirements and preferences [1, 9, 10, 11, 17]. More detailed description of the unified user interface development environment, methods and tools can be found in http://www.ics.forth.gr/~access.

3.1 Unified User Interfaces in Practice: The AVANTI Web Browser

The ACTS AC042 AVANTI Project aims to address the interaction requirements of disabled users using Web-based multimedia telecommunications applications and services. The main module of the AVANTI system are [2, 5, 6, 15]: (i) a collection of multimedia databases which can be accessed through a common protocol (HTTP) and provide mobility information for disabled people; (ii) the AVANTI server which maintains knowledge regarding the users, retains a content model of the information system and adapts the information to be provided, according to user characteristics (hyper-structure adaptor); and, (iii) the unified browser interface layer, which is capable of adapting itself to the abilities, requirements and preferences of individual users.

The AVANTI Web Browser (acting as a front-end to the AVANTI system) aims to provide accessibility and high quality interaction to all potential users. Following the Unified User Interface Design methodology, a unified browser layer has been developed, which addresses the different abilities and skills, and diverse requirements and preferences of a wide range of users, including disabled and elderly people. Lexical and syntactic adaptability and adaptivity techniques are applied to the unified browser, in order to provide accessibility and high quality interaction to able-bodied, motor-impaired and blind users.

The AVANTI Web browser features the following input / output devices: binary switches; speech input (command recognition); joystick and touch-tablet input; Braille display output; speech output; digitised audio output; and special keyboard functionality. Also, it includes the following features: enhanced history control for blind users, as well as linear and non-linear (graph) history visualisation for sighted users; resident pages that enable users to review different pieces of information in parallel; link review and selection acceleration facilities; document review and navigation acceleration facilities; enhanced mechanisms for document annotation and classification; and enhanced intra-document searching facilities [14].

Figure 1 shows a screen shot of the prototype AVANTI user interface. Styles that have been activated due to adaptability decisions include: enabling of the scanning mechanism for use by severely motor impaired users (extra window manipulation toolbar in (1), and scanning focus in (5)); representation of links as buttons (as opposed to more "traditional" browser representations, as highlighted or underlined text) to facilitate interaction by users novice in hypermedia (2); activation of the link-bar (a separate pane containing all the links in an HTML page), for easy review and selection by motor-impaired users (3). Furthermore, in the screen shot the activation of a style is shown (4) which provides interface usage information to the user, as a result of an adaptivity decision triggered by the fact that the user is not making "correct" use of the interface.

Figure 1 - A Screen Shot of the Prototype AVANTI User Interface

4. Concluding Remarks

The proliferation of computer-based systems and interactive applications in every walk of life and the anticipated widespread use of telematic services creates numerous new opportunities, but also presents challenges and entails risks. This paper has focused on the proactive realisation of the design for all principle in HCI, and has outlined recent efforts towards the development of user interfaces for all. The main argument of the paper is that universal design in HCI, i.e. designing interfaces for the broadest possible population, including disabled and elderly people, is more of a challenge than a utopia [18]. This is grounded on the firm experiences, in the light of the results of various research and development projects and other international initiatives.


Part of this R&D work has been carried out in the context of the following projects:

(a) TIDE TP1001 ACCESS project, partially funded by the European Commission (DG XIII). The ACCESS consortium comprised the following organisations: CNR-IROE (Italy) - Prime contractor; ICS-FORTH (Greece); University of Hertforshire (United Kingdom); University of Athens (Greece); NAWH (Finland); VTT (Finland); Hereward College (United Kingdom); RNIB (United Kingdom); Seleco (Italy); MA Systems & Control (United Kingdom); PIKOMED (Finland).

(b) ACTS AC042 AVANTI project "AdaptiVe and Adaptable INteractions to Multimedia Telecommunications ApplIcations", partially funded by the European Commission (DG XIII). The AVANTI consortium comprises: ALCATEL Siette (Italy) - Prime contractor; CNR-IROE (Italy); ICS-FORTH (Greece); GMD (Germany); University of Sienna (Italy); MA Systems (UK); MATHEMA (Italy); VTT (Finland); ECG (Italy); University of Linz (Austria); TELECOM ITALIA (Italy); EUROGICIEL (France).


[1] Akoumianakis D. and Stephanidis C., "Supporting User Adapted Interface Design: The USE-IT System", Interacting with Computers, 9(1), 1997, pp. 73-104.

[2] Andreadis A., Marchigiani E. and Rizzo A., "The AVANTI Project: Prototyping and Evaluation with a Cognitive Walkthrough Based on the Norman's Model of Action", ACM Conference on Designing Interactive System: Processes, Methods and Techniques (DIS), 1997, pp. 305-309.

[3] Bevan N., "Measuring Usability as Quality of Use", Software Quality Journal, 4, 1995, pp. 115-130.

[4] Bevan N. and Azuma M., "Quality in Use: Incorporating Human Factors into the Software Engineering Lifecycle", 3rd IEEE International Software Engineering Standards Symposium and Forum, 1997, pp. 169-179.

[5] Emiliani P.L. and Bini A., "Information about Mobility Issues: The ACTS AVANTI Project",4th European Conference for the Advancement of Assistive Technology (AAATE), 1997, pp. 85-88.

[6] Fink J., Kobsa A. and Nill A., "User-Oriented Adaptivity and Adaptability in the AVANTI Project",Microsoft Conference: Designing for the Web - Empirical Studies, 1996.

[7] ISO / IEC 14598-1, Information Technology - Evaluation of Software Products - Part 1: General guide. International Standards Organisation, Geneva, Switzerland, 1998.

[8] Sandhu J.S., "What is Design for All", European Telematics: Advancing the Information Society Conference, 1998, pp. 184-186.

[9] Savidis A., Paramythis A., Akoumianakis D. and Stephanidis C., "Designing user-adapted interfaces: the unified design method for transformable interactions", ACM Conference on Designing Interactive System: Processes, Methods and Techniques (DIS), 1997, pp. 323-334.

[10] Savidis A., Stephanidis C. and Akoumianakis D., "Unifying Toolkit Programming Layers: a Multi-Purpose Toolkit Integration Module", 4th Eurographics Workshop on Design, Specification and Verification of Interactive Systems (DSV-IS), 1997, pp 177-192. [11] Savidis A., Stephanidis C. and Emiliani P.L., "Abstract Task Definition and Incremental Polymorphic Physical Instantiation: The Unified Interface Design Method", HCI International '97 Conference, 1997, pp. 465-468.

[12] Stephanidis C., "Towards User Interfaces for All: Some Critical Issues", HCI International '95 Conference, Panel Session "User Interfaces for All - Everybody, Everywhere, and Anytime", 1995, pp. 137-142.

[13] Stephanidis C., "Towards the Next Generation of UIST: Developing for All Users", HCI International '97 Conference, San Francisco, USA, 24-29 August 1997, pp. 473-476.

[14] Stephanidis C., Paramythis A., Karagiannidis C. and Savidis A., "Supporting Interface Adaptation in the AVANTI Web Browser", 3rd ERCIM Workshop on User Interfaces for All, 1997. Available electronically at http://www.ics.forth.gr/proj/at-hci/UI4ALL/UI4ALL-97/proceedings.html.

[15] Stephanidis C., Paramythis A., Savidis A., Sfyrakis M., Stergiou A., Leventis A., Maou M., Paparoulis G. and Karagiannidis C., "Developing Web Browsers Accessible to All: Supporting User-Adapted Interaction", 4th European Conference for the Advancement of Assistive Technology (AAATE), 1997, pp. 233-237

[16] Stephanidis C., Salvendy G. Akoumianakis D., Bevan N., Brewer J., Emiliani P.L., Galetsas A., Haataja S., Iakovidis I., Jacko J.A., Jenkins P., Karshmer A.I., Korn P., Marcus A., Murphy H.J., Stary C., Vanderheiden G.C., Weber G. and Ziegler J., "Towards an Information Society for All: An International R&D Agenda", International Journal of Human-Computer Interaction, 10(2), 1998, To Appear.

[17] Stephanidis C., Savidis A. and Akoumianakis D., "Unified Interface Development: Tools for Constructing Accessible and Usable User Interfaces", Tutorial no 13, HCI International '97 Conference, San Francisco, USA, 24-29 August 1997. Available electronically at http://www.ics.forth.gr/proj/at-hci.

[18] Stephanidis C. and Akoumianakis D., "Designing for All in the Information Society: A Utopia or a Challenge?". Submitted for Publication.

[19] Vanderheiden, G.C., "Thirty-Something Million: Should they be Exceptions", Human Factors, 32(4), pp. 383-396. Available electronically at http://www.trace.wisc.edu/text/univdesn/30_some/30_some.html.

[20] Weijers T., "Assessing the Application of the Design for All Approach", European Telematics: Advancing the Information Society Conference, 1998, pp. 266-268.

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