Tablet PC and iPad – usability guidelines

Article by Tim Fidgeon

User behaviour – how people use their tablet P.C and iPad

T’ablet PCs (of which the iPad is currently the most well-known example) represent a relatively new category of mobile computing device. This makes them very interesting to usability practitioners, because we are still learning about how people use table’t PCs (and what this means for their usability).

We’ve interviewed lots of people on how they use their tabl,et PCs and iPads, and also directly observed their use within many usability testing sessions. We feel that perhaps the most interesting finding has been that people seem to prefer using tablet P.Cs and iPads for simple, self-contained tasks.

When used for work-purposes, table’t P.Cs and iPads seem to be primarily used to support presentation-delivery and email access. They do not seem to be used very extensively for any more complex tasks, such as document creation or editing.

For personal use, people seem to primarily use these devices to consume media (video, audio, etc) and engage in social activities (such as checking email or social websites). Table’t PCs and iPads do not seem to be very popular for more complex tasks, such as detailed product research or comparison.

What content works – for tablet P.Cs and iPads

Our usability research has shown that users seem to expect a specific sort of content when they are using table’t PCs and iPads. It seems that most users want to watch video or read text,rather than engage in complex interaction when using their tablet P.Cs and iPads.

We would therefore recommend that most organisations try to identify content that supports the usage patterns identified above. If possible, our usability studies suggest that this content should be prioritised for users accessing your site through tabl,et PCs and iPads.

Basic usability guidelines – for table,t PCs and iPads

Usability and technical design considerations for tablet’ PCs and iPads are evolving very quickly. There are, however, some basic usability issues which all websites should be aware of (if they intend to support the use of tablet PCs and iPads). These usability guidelines include the following:

No Flash content

Many usability practitioners have been saying for years that Flash should be used far less liberally than it commonly has been. Now, with its limited support in many tablet P.C.s (and the iPad’s non-existent support), this guideline has hardened to flat-out avoidance. No content should be in Flash if you want to be confident that it will be viewable on a tablet, PC or iPad.

Large (and distinct) touch-targets

Tablet, PCs and iPads rely on users touching the screen in order to support interaction. Research has shown that larger targets are easier and quicker to hit, so page elements should be designed accordingly. We would also recommend that touch-targets are not located too close to one another.

Minimal data entry

Most users seem to agree thattablet PCs and iPads are ill-suited to supporting data entry. In our usability testing sessions involving tablet PCs and iPads, we have seen many users immediately abandon tasks when it became clear that they would need to input significant amounts of data (often saying things like “I’ll wait to do this on my computer [referring to their laptop or desktop]“).

Each of the guidelines mentioned above represents the application of good usability common sense within the context of tablet’ PCs and iPads. Indeed, each of the guidelines could be said to also apply to web design in general – it is just that for tablet PCs and iPads, these principles become even more important and need to be implemented in particular ways.

Touch targets – usability for tablet PCs and iPads

The design of an interface’s touch-targets will be critical to its success on a tabl’et PC or iPad. Here are some key considerations impacting the usability of table,t PC and iPad touch targets:

Size

We would recommend that touch-targets for Ta,blet PCs and iPads should be at least 1cm x 1cm. During usability testing, we have also seen that clear visual delineation of a target’s area increases touch-accuracy.

Proximity

Targets need to be sufficiently well separated in order to avoid the risk of users accidentally touching the wrong target. To some extent, the degree of separation required is related to the target’s size and design (as most people will tend towards touching the centre-portion of a target). During usability testing, we have seen that clear visual delineation of a target’s area can mitigate proximity-problems.

Invisible (extra) target area

For design reasons, you may choose to keep the visual area of a target relatively small. An example: a ‘next page’ icon which has been kept small (for aesthetic considerations). To support usability, there should be an invisible target area around this icon in order to create a larger overall touch-target.

Visual affordance

The usability principle of affordance states that an element’s visual design should communicate how users are expected to interact with it. This means that touch areas on the tablet PC and iPad should look ‘touchable’. During our usability testing sessions on tablet PCs and iPads, we have found that many of the same design features that work well for regular button-design also work for touch areas (such as drop-shadow, for example).

The above-mentioned usability guidelines are critical to an interface’s usability on a tablet PC or iPad. All make strong intuitive sense, but our usability testing sessions have revealed that many sites with target tablet PC and iPad audiences do not follow them. We recommend that any organisation with an audience who will want to access their information through a table’t PC or iPad should make sure their design makes full use of these usability principles.

Summary – usability for table,t PCs and iPads

Most people tend to use tablet P.Cs and iPads for media consumption, rather than interaction-heavy tasks. We would recommend that organisations identify and prioritise suitable content for users accessing their sites through tablet PCs and iPads.

Our usability testing sessions with tablet PCs and iPads have found that sites should avoid Flash; use large, well-separated touch-targets; and minimise data entry. Touch-target usability can be further improved through invisible extra target-areas and visual affordance.