Tablet PC and iPad – Usability guidelines

5 September 2011
Tim Fidgeon

Author: Tim Fidgeon

Tim is a trainer and consultant who has worked in the fields of digital design, usability and marketing since the 90s.

Tablet PCs are mostly used for passive consumption, rather than interaction-heavy tasks. Interfaces should avoid Flash; use large, well-separated touch-targets; and minimise data entry.

User behaviour – how people use their tablet PC and iPad

Tablet 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 tablet PCs (and what this means for their usability).

We’ve interviewed lots of people on how they use their tablet 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 PCs and iPads for simple, self-contained tasks.

When used for work-purposes, tablet PCs 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). Tablet PCs and iPads do not seem to be very popular for more complex tasks, such as detailed product research or comparison.

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What content works – for tablet PCs and iPads

Our usability research has shown that users seem to expect a specific sort of content when they are using tablet 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 PCs 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 tablet PCs and iPads.

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Basic usability guidelines – for tablet 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 PCs (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 that tablet 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.

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Touch targets – usability for tablet PCs and iPads

The design of an interface’s touch-targets will be critical to its success on a tablet PC or iPad. Here are some key considerations impacting the usability of tablet PC and iPad touch targets:

  • Size
    We would recommend that touch-targets for Tablet 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).

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Summary – usability for tablet PCs and iPads

Most people tend to use tablet PCs 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.

About the author – usability for tablet PCs and iPads

This article was written by usability and online copywriting expert Tim Fidgeon, who works with Spotless Interactive – a leading usability consultancy. Spotless Interactive are experts in all areas of usability testing and user-centred design.

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