This paper has examined a number of case studies where designers had striven to develop products to meet the needs of the widest possible sets of users, but had not quite achieved the outcomes desired. Each case study highlighted different issues that, taken together, make for a useful set of reminders for all the designers:
If the designer does take a step back to reflect and consider, it is helpful to have some idea of what to look for. The aim of the guidelines presented here is to support those moments of reflection and to provide a complementary set of rational checks to ensure that the design is not inadvertently heading towards a dead-end.
8.1 Applying the guidelines
Looking at each guideline in turn, it can be seen how they can be applied in practice when designing and developing new devices or products.
Guideline 1—Logitech was not the only company developing a mouse based on Immersion’s haptic technology. A number of specialist assistive technology companies did the same. However, the Logitech mouse cost an average of $80–$100, whereas the specialist ones developed explicitly for users with motor impairments typically cost $1000. Needless to say, very few were sold. Cost effectiveness simply cannot be ignored in most situations.
Guideline 2—examples of failing to consider all the aspects of interaction include developing auditory navigational assistants for people who are blind that require the user to wear headphones to hear the instructions, but that also simultaneously stop them from hearing approaching cars as they attempt to cross a street. Interaction with a device can incorporate many facets and stages, using a range of modalities and senses. Accessibility issues can arise in any of those facets or stages, so they must all be considered.
Guideline 3—it has to be borne in mind that many users with moderate-to-severe functional impairments often need to work extra hard to compensate for the impairments. As such, it becomes particularly difficult for them to cope with significant additional demands placed upon them by the device that they are trying to use. For example, asking a user with tremor to have to keep their hands still to complete a task is unlikely to be successful.
Guideline 4—as with guideline 3, users with moderate-to-severe functional impairments are less likely to be able to avoid injury when using a product that is unsafe. It is particularly important to ensure that all avoidable risks and dangers are removed for the users.
Guideline 5—the definition of “inappropriate” and, by extension, “appropriate” paradigms is largely dependent on the task being considered. It is important to bear in mind that the more the interaction paradigm is based on the obvious options available to the users, the better it is for them. The problem highlighted in the digital television example given in this paper was that the designers had tried to import a computer interaction paradigm into am established television context and had made a little attempt to introduce the users to the new paradigm. It would have been better to extend the established interaction paradigm rather than try to introduce a wholly new one with no explanation and where it had no obvious connection to the task at hand. What may make sense for one person may not make sense for another person.
Guideline 6—as an extension of guideline 5 above, the use of the computer-based paradigm for the digital television example made sense for the designers, because they were presumably used to using computers, so the new paradigm made sense to them. However, the users who evaluated the set-top boxes were not experienced computer users, so the paradigm was both unknown to them and unrelated to the task. This was not the only example in this paper where designers had assumed that users were used to something, only to discover that they were not. The best way to avoid such problems is to get to understand the users more completely rather than blithely making assumptions about them. Approaches such as user-centred design and user-sensitive design have been developed precisely to avoid such issues.
Guideline 7—this guideline is primarily focused on ensuring that the designers remember the users, especially when developing a new technological solution that requires significant innovation and/or invention to make it work. There is a little point in developing an innovative new technology that the users will not use no matter how cool the new solution may be. It is under such circumstances, with heavy time-pressures and deadlines with a new technology that is stubbornly refusing to work that the needs of the users can be forgotten. However, to forget them will lead to a product or device that still will not work, albeit for different reasons, i.e., the user cannot use it rather than, because the technology was incomplete.
Guideline 8—the history of the development of new assistive technologies is littered with examples of products that seemed to be technologically sound, but simply do not take off in the marketplace. Usually, the reason is because the users just do not see the value in investing their money or their time and effort in buying, learning to use and maintaining the product or device. However, there are plenty of examples of devices that serve little useful purpose, but still sell very well, such as the Tamagotchi craze of the 1990s or loom bands a few years ago. The important point here is that the users need to see a value in the product or device to want to put the effort in to own one. Designers sometimes become convinced that a device or product will be purchased based solely on its technical merits, but that is rarely the case.
Guideline 9—the thought process that a new product needs to finish its technical development first and foremost and that the interface can be bolted on afterwards is still a difficult one to shake, no matter how many usability texts make it clear that this is not the correct way to proceed. Put simply, a product or device with a poor interface will still fail as badly as one that is incomplete technically, e.g., one that may not offer all of the desired functionality. The products that typically succeed best in the marketplace combine technical completeness, correct price point, and sufficient usability/accessibility. If a product does not offer all three features, it is likely to fail. It is better to adjust the development timeline to allow time for all the development to be completed sufficiently than to rush to market with major flaws. If the development of the technology is proceeding more slowly than expected, it is better to adjust timelines and project management than to just assume that the users will not notice a poor interface.
Guideline 10—put simply, if a design team is young and predominantly male, but the intended users are notably older and primarily female, there will be significant differences between the users and designers, such as their respective mean heights, strength and so on. Likewise, as people age, their irises typically become more yellow, making it harder to distinguish between yellow and white. It can be hard for one group of people to fully understand the capabilities and attributes of another group. One possible solution is the use of simulation aids to mimic the effects of impairments [
14].
Guideline 11—as discussed earlier, users with functional impairments may struggle to complete certain tasks that those without the impairments may experience no difficulty with. This is the point at which impairment becomes disability. Sometimes users are able to adapt a product or device to meet their needs, but this is often a highly personal situation and not usually appropriate for many others. For example, there have been cases where people who are deaf and non-speaking have found mobile telephones to be useful, but as a way of sharing text typed on them with those they are trying to communicate with, e.g., in a shop with a sales assistant who can also see the screen, rather than as a telephone for making calls. However, such instances are comparatively uncommon. More commonly, though, people with more profound functional impairments typically take more time to learn and adapt to new technologies. It is best to minimise the amount of superfluous learning effort wherever possible, so using devices that relate explicitly to the task at hand are likely to be more useful than those that are more general purpose. An example was the comparative usability of remote controls designed explicitly for use with a set-top box compared with the perceived poor usability of general purpose remote controls that had been re-programmed for use with such devices.
Guideline 12—guideline 2 addressed all the stages of interaction between the user and the product or device. However, while that guideline was focused more on the primary uses of the product, e.g., a remote control for watching television, it is also necessary to think more broadly about all aspects on the ownership life cycle of the product/device. For example, in addition to using the product/device, designers need to consider all the steps such as buying the product, unpacking it, setting it up (including programming it, where appropriate), decommissioning it, and ultimately disposing of it. Each of these steps has its own range of interaction processes and requirements and all of these need to be considered for the ownership experience to be a successful one for the user.