By Gerd Waloszek, SAP AG, SAP User Experience – December 5, 2007
Universal usability is a fairly new concept in the user interface design field. This article explains what universal usability means and how it is related to similar concepts, such as universal access and universal design.
Universal usability refers to the question of how information and communications products and services can be designed so that they can be used by every citizen. The term was introduced by Ben Shneiderman in an article, titled Universal Usability and published in the Communications of the ACM (see references) in 2000. In the article, Shneiderman outlines a research program for addressing the "universal usability challenges" of:
According to Shneiderman (2000), these three challenges are the main obstacles for making information and communication services available to every citizen, or as he puts it, "in attaining universal usability for Web-based and other [information and communication] services."
Shneiderman (2000) also provides a practical/measurable definition of universal usability:
Besides universal usability, there are two related terms in use: universal access and universal design. Although these terms have a somewhat different meaning (see here) they are often used interchangeably with universal usability. All in all, however, universal usability can be regarded as the broadest concept of the three because it includes both access and usability. And implicitly it subsumes, of course, design, too. On the other hand, the authors of the Wikipedia article about universal usability * argue that these three concepts can been seen as complementing each other: "Altogether [they] cover, from the user's end to the developer's end, the three important research areas of information and communications technology (ICT): use [universal usability], access [universal access], and design [universal design]."
For more information, see definitions of universal access and universal design and the relationships between all three concepts.
Pioneers in the field of universal usability include Gregg Vanderheiden (Trace Center, University of Wisconsin – Madison, USA), Constantine Stephanidis ("User interfaces for all", ERCIM), Alan Newell (University of Dundee, Scotland), Vicky Hanson (T.J. Watson Research Center, IBM, USA), Ben Shneiderman ("Universal usability", University of Maryland, USA), and Jonathan Lazar (editor of the book Universal Usability; Townson University, USA).
Shneiderman conceived universal usability as a research agenda. His focus on research may be the reason, why the recently published anthology Universal Usability (2007; edited by Jonathan Lazar; see review), mostly takes an academic approach when presenting recent results from the field. In my opinion, universal usability deserves a much broader audience than solely the research community. Designers and also practitioners should be familiar with this topic and its implications.
Below, I will illustrate what Shneiderman's three challenges mean in practice using real-world examples.
Supporting a broad range of hardware, software, and network access means to support:
Accommodating individual differences among users means to support users who differ with respect to:
In real life, these criteria can usually be found in combination. For example, pre-school children are young (age), cannot read (literacy), and also have lower motor skills than older children and adults (a kind of "disability"). As another example, members of under-privileged groups typically have deficiencies in literacy, computer literacy, and education and also have a low income.
Coarse categories for classifying these differences might be:
In my opinion, this third challenge differs from the other two because it refers exclusively to the users' knowledge levels. It corresponds more or less to the category "computer literacy," which I added to the "user diversity" challenge and might be subsumed under that label as well. Nonetheless, designing and implementing software and information services, which accommodate users with pronouncedly different degrees of proficiency is a huge challenge in itself.
Possible categories for classifying differences in user knowledge and usage behavior are:
For example, frequent use does not necessarily imply that the user has an advanced level of knowledge, because the usage may be confined to simple functionality or just one application.
According to Jonathan Lazar (2007), there are essentially two types of universal interface design strategies:
Which of the strategies is chosen, depends on how the software or device is to be used. Note that this distinction can be extended beyond software or electronic devices to include houses, appliances, or any other objects in our daily lives.
Universal solutions raise the question of how different user populations can be best accommodated. Is it better to use multiple solutions or just one? The need to accommodate a wide range of users implies that there is no "average" user on whom a system design can be based. Consequently, a single design that accommodates the diversity of the prospective users and their needs often simply does not exist. Therefore, the authors of the Wikipedia article regard multi-layer systems as the most promising approach to achieving universal usability to-date. These systems accommodate different users through multiple interfaces, such as multiple versions of adjustment controls, or variable numbers of options to select from.
An alternative to true multi-layer designs would be to provide one "mainstream" solution and add specific solutions for certain user populations to broaden the range of users. Which of the approaches is more costly depends on the situation at hand. Clearly, multi-layer interfaces are more expensive to build than single solutions. But they may be more cost-effective than a mix of distinct solutions. This is particularly the case if specific solutions have to be added later on, for example, when the need arises to conform to legal requirements.
Shneiderman (2000) also emphasized the usefulness of layered approaches: "They are easy to implement when planned in advance, but often difficult to retrofit." As a rule of thumb, we might state that implementing features that are needed by specific user groups afterwards can be much more difficult and expensive than implementing them from the very start. Advocates of universal usability like to use the analogy of curb-cuts to explain how systems designed for disabled users can benefit all users. Curb-cuts are scooped-out pieces of sidewalk to allow wheelchair users to cross streets. They are also useful for baby carriage pushers, delivery service workers, cyclists, and travelers with roller bags. The curb-cut analogy also illustrates Shneiderman's above-mentioned statement: Adding curb-cuts later can be very costly and in some cases even impossible. Transferring this idea to electronic systems, the authors of the Wikipedia article conclude: "It might be expensive to transform an existing system to meet universal usability standards, but the extra cost of integrating electronic curb-cuts into a new system can be minimalized."
Accommodating a wide range of users and technological options calls for a certain amount of flexibility in the design of systems. Critics of universal usability warn that the flexibility, which is required by universal usability, may lead to resorting to "lowest common denominator systems," or "dumbing down" technologically (this is also called the "innovation restriction scenario"). As an example, in her book Access by Design, Sarah Horton favors HTML over all other Web formats and requires Web designers to use non-standard formats, such as Flash or PDF, only as alternatives to HTML, not as the only solution. I doubt that all Web designers will agree with her point of view; some will feel deprived of the technical options that the non-standard formats offer. Ben Shneiderman (2000), however, is optimistic and believes that "accommodating a broader spectrum of usage situations forces researchers to consider a wider range of designs and often leads to innovations that benefit all users." Some frequently-cited examples demonstrate the possibility of benefits for all users, but I would argue that the "ecological" validity of this statement has yet to be proven. Or perhaps I should say, that its "economic" validity has yet to be proven? Reality has repeatedly shown that economic considerations, and also ignorance about the needs of specific user populations, seduce designers into providing solutions, which are only targeted at "main-stream" user populations. Universal designs are still the exception, not the rule. Last but not least, this is also a political and a social issue. As section 508 demonstrated, sometimes the pressure of legal requirements can act as a driving force towards universal access and usability.
Below, I will list some example applications of universal usability.
According to Wikipedia, current trends in the universal usability research include (adapted):
(W) Example from Wikipedia; (IBM) from IBM's Web Adaptation Technology Website
To my knowledge, little work has been done regarding the question of how to bridge gaps in user knowledge. Examples of current research approaches are:
Practical solutions include:
All of these approaches attempt to provide users with the necessary knowledge. Systems that emphasize training and teaching usually do so in advance (or proactively), while help systems (and cheat sheets) are used "on the spot," that is, during the actual work. Written documentation can be used for both purposes. Adaptive systems take the users' current knowledge level into account to make sure that they are provided with just the information they need. For example, adaptive systems ensure that experts are not overwhelmed or distracted by information they already know. Typically, all these approaches are covered under an educational or instructional umbrella, not a universal usability one. Therefore, I will not go into further detail here.
In addition, there are some general usability concepts that help to bridge the gaps in user knowledge, such as:
Universal usability is an ambitious goal, which is hard to reach, given the challenges posed by user diversity and technology variety. Strategies to attain this goal can largely be divided into (1) solutions that attempt to accommodate as many users and technologies as possible and (2) solutions that are targeted at specific user populations. While the first approach strives for universal solutions, the second one is not at all universal. Instead, by targeting specific solutions, it strives to broaden the range of users who have access to information technology and services. Specific solutions may have the – often unexpected, but welcome – potential to be adopted by other users as well, provided they benefit all, or at least a wide range of users. In such a case, we are indeed "at the heart" of universal design.
When advocating universal usability, some authors adopt a strict position, while others are willing to make compromises. However, being too strict implies the danger of being not listened to or being accused of limiting people to low-level technology (or the lowest common denominator). As an example, some authors demand only HTML is used for Web pages because it is the most universal technology. The reality of the Web tells us that the majority of the Websites simply ignore such strict requirements. As it stands, this issue has not been settled yet – partly because of the additional cost that specific solutions or greater flexibility introduce, partly because of unawareness for the issue of universal usability itself. However, the goal of universal usability is too important to be left aside and ignored. Greater activity and publicity is needed to make it succeed. This article is one more attempt to make people aware of universal usability and give its case more impetus.
Feedback to this article and suggestions for improving it are welcome!
*) The Wikipedia article about universal usability is a group project of Dr. Kent Norman's Spring semester 2006 course, Seminar in Human Performance Theory: Human/Computer Interaction, at the University of Maryland, College Park. As there is no single author, we will use the authors of the Wikipedia article, or short, Wikipedia as author name in the remainder of the article.