Ensure that information can be understood by all users
People with low literacy, reading disorders, cognitive or intellectual impairments may have difficulty reading, understanding and remembering text and graphical symbols that are not simple, familiar and unambiguous. The overall complexity of the interface may also present problems for some users, as illustrated in Case Study 2: A lot of things can be too complicated.
Directions and techniques
Allow sufficient time (high priority)
The maximum allowed response time for user-activated actions should allow for people who find these operations slower to perform, either because they are unfamiliar or due to limited dexterity. This can be achieved by providing options to turn off, adjust, or extend the time limit. This includes operations that require buttons to be pressed in sequence (e.g. selecting channel numbers greater than 9). This should include options to retaining the display of information chosen by the user (e.g. the programme synopsis) until the users decides to remove it.
This requirement does not apply to real-time events, where a time limit is absolutely necessary (e.g., interacting with a live television quiz show).
Allow users to reduce the complexity of the interface (high priority)
Users should be given the option to reduce the amount of information or functionality displayed in the user interface.
(a) Grid view, showing all channels, scrolling vertically by channel and horizontally by time.
(b) List view, showing only one channel, scrolling vertically by time.
This can be achieved by providing two clear options a simple interface and a full interface. An example of this, shown in figure 4, is the different view options that can be available in a programme guide a grid view showing all channels with scrolling in two directions and a list view showing only a single channel with scrolling only in one direction. The best approach may be for the default interface to be simple, with the option of increasing the information or functionality for those who want more.
Use simple language and intuitive symbols
Acronyms, abbreviations and jargon words should be avoided in preference for complete, standard words and phrases.
For numbering, use Arabic numerals (1, 2, 3,...) which are more recognisable and easier to understand than Roman numerals (I, II, III, i, ii,...).
For symbols, follow universal design guidelines and common industry standards. A good source of guidance with a listing of applicable standards is the Tiresias guidelines on Pictograms, Icons and Symbols.
For English language instructions or explanatory text, follow Plain English Guidelines as far as possible. Guidance on how to write instructions and descriptions in Plain English is available on the Simply Put website.
Reinforce text with graphical symbols
Explanatory images or pictograms should be provided as an aid for people who have difficulty understanding or reading text. Icons should be designed to be both recognisable and memorable. Figure 5 shows some examples. To find out whether these are recognisable and memorable, user testing would be required.
Reinforce graphical symbols with text labels
Provide an additional text label with graphical symbols, to help people who have difficulty understanding the symbol.
How you could test for this
To find out whether efforts to make information understandable will be successful, it is necessary to test prototype designs with a wide range of users, including people with low literacy, cognitive impairments and reading disorders.
Further tests could also be included within general long term user trials encompassing the whole process of setting up, learning and using the equipment.