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The principles of usability have been established for more than sixty years, and increasingly companies are claiming that their products are designed for ease of use. However, there is evidence that usability practices and the benefits they deliver are not making it to the product line.

Technology is becoming increasingly important in every aspect of our lives: from mobile phones and media players that we can carry with us every day, to those we install in the heart of our homes such as digital television (DTV) and other entertainment systems. Given its pervasiveness, usability should be central to all these technologies.

Currently more than 40% of households have access to digital television, and the Government’s aim is to reach 99% coverage by 2010. Suppliers are already relying on promoting the ease of use of digital television services such as Electronic Programming Guides as a tempter for people reluctant to make the switch to digital television. However, study of real usage of existing products and services reveals that the well established principles of usability are not being adhered to.

In this short article we look at three elements of the currently available Sky Digital television package: Favourite Channels, Programme Planner and Interactive channels. The first two of these are simple facilities aimed at enabling users to get the most from digital television use. As such they should be simple, straightforward and consistent to use. However we will show that this is not the case. Given the failure to demonstrate good usability in even basic components of the digital television experience, it is perhaps not surprising that a more complex offering such as interactive channels also have serious usability failings. However, given the importance of such high-profile, and well-promoted features to DTV providers, it would not seem unreasonable to expect a higher level of attention to usability in the design.

Favourite Channels

With more than 100 channels available to a user in a typical viewing package the favourites feature, which allows a subset of channels to be marked and navigated is very useful. However, examination of a typical interaction sequence reveals some considerable obstacles to effective use. For example, consider a user browsing channels and finding one that is particularly to his/her taste. An interesting programme is currently showing and the user wishes to add this channel to their favourites. On selecting a channel, the user is presented with options to search time, search channel or search favourites. These are displayed for approximately five seconds.

Although these are useful features, there is no way to add the currently viewed channel to the favourites group. To achieve this, the user has to determine the channel number, which is not displayed on the screen or in the information pop-up, but can be found by using the search functions. The user must then commit the channel number to memory, must press the services button on the handset, select option 5 (favourite channels), and scroll/page through the list of channels until the desired channel number is located (no search or number entry function is provided). When the desired channel is located instructions inform the user to press the yellow button on the handset to mark the channel as a favourite. This is then indicated by a tick next to the selected channel. Pressing the yellow button again unmarks the channel. Further instructions tell the user to press the select button when complete. However this instruction presents the word select in a yellow surround, causing potential confusion with the yellow handset button, which as noted would unselect the channel from favourites. Pressing select returns the user to the services menu. They must then press ‘backup’ to return to the channel they were originally watching. Throughout this entire interaction, the programme sound is muted and no programme picture is available.

So, in what should be a straightforward interaction sequence the following usability issues are noted:

• The sequence takes the user away from the primary goal – that of watching the desired programme/channel.

• The information required (channel number) to complete the task is not readily available to the user.

• The user is required to commit important information to memory and recall it several steps into the task sequence.

• There is conflict in the colour coding used for different steps in the task sequence.

• At the end of the task sequence the user is not returned to their starting point (the desired programme/channel).

Programme Planner

The programme planner function allows the user to select programmes that they wish to watch and set reminders against them. Unlike the favourite channel function, the reminders can be set from specific channels by using the “search time” function and then pressing select. This is very useful. However, it is not possible to enable the auto-view or series link functions without navigating to the personal planner pages.

The personal planner is accessed from the electronic programme guide (in contrast to Favourite Channels, which is located under services). This lists all reminders that have been set, and enables related functions such as auto-view and series link to be activated. The reminders are indicated by a green clock icon. However there is no link between the green icon and the green button on the handset. Infact the green button on the handset is used to set series links. Again, in this function there is a conflict between the colour coding used for separate functions: the yellow button being used to delete an item from the personal planner and the instruction ‘backup’ presented on a yellow background to exit the personal planner.

Although it is a relatively simple matter to set a reminder whilst watching a particular channel, it is another matter to remove reminders. If a user tries to set a reminder for a programme that clashes with another programme which has already been entered into the personal planner, the only options open to them are to add in the second programme, accepting the clash, or to cancel the selection. It is not possible to delete or overwrite the first programme entered into the planner. To do this the user must leave the channel they are viewing and navigate to the personal planner.

So again we see that a supposedly simple and potentially useful function demonstrates a host of usability issues. There are, however, developments in the programme planners available on digital television, for example the planner offered for UKTV channels which shows context sensitivity (e.g. “if you liked this then try…”) and allows in-picture viewing, as well as allowing the user to view now and next programming for a related subset of channels. As yet, this facility does not integrate with reminder functionality or support one step channel changing (the user must exit the listing and then enter the specific channel number).

Interactive Channels

Digital television offers many potential benefits to users in the shape of interactive channels. The most sophisticated of these offers sports and news coverage with a large amount of control in the hands of the user. Many interactive channels are available; a review of some of these reveals the following usability issues:

• Picture-in-picture format is too small for meaningful viewing on standard sized televisions;

• Unreadable text (colour clashes and inappropriate font sizes);

• Lack of on-screen instructions for navigation;

• Limited support for navigating and selecting from lists/menus;

• Delays in caption updating leading to a mismatch between visual and textual content;

• Conflict between the layout of colour-coded buttons on the screen and handset.

Such channels are continuously evolving, and improvements in usability are in evidence with each new release. As market advantage is generally achieved through content-coups, there would be room within the industry for standardisation on the better interaction methods and techniques.

This article provides a brief introduction to some of the usability issues associated with digital television. For further information about the services Corporate Solutions offer to achieve greater usability and consumer focus in interactive media please contact us.