DASH – Design for All Self Help
Manual for Digital Designers
Date: 04/07/2007
Article
We acknowledge technical advice from Designed for All Ltd but any errors are ours.
Introduction
DASH (Design For All Self Help) is a set of simple guidelines which will enable designers of digital information systems and user interfaces to optimise accessibility:
- Design for All - as a statement must not be taken literally; no system can be designed to accommodate all the needs of all potential users
- Self Help - The guidelines are simple so that they can be followed without a training course or a bulky manual
- Optimise - In this context means to cater for the maximum number of needs consistent with budget and simplicity
- Accessibility - is the aspect of usability relevant to people with physical or cognitive impairments or disabilities.
DASH is used in its two senses: good results can be achieved quickly; a little goes a long way.
Chapter 1 - Information System Goals
In designing digital information systems and user interfaces, it is vital to bear in mind the ordering of goals for information access [1]:
Summary
Information goals in sequential order:
- Acquisition
- Perception
- Cognition
- Integration
- Intent
- Navigation
- Interaction
- Creation.
Explanations of User Goals
1 Acquisition
1.1 For most digital information systems the point of acquisition is the on/off switch. These are not always obvious and many are not fit for purpose because they are too small or require highly focused physical pressure.
1.2 This concept also includes the environmental context of the device, taking into account such factors as:
- Physical positioning that accommodates the use of controls, hearing or viewing output
- Ambient conditions, e.g. the relationship between the information device and surrounding conditions such as the effect of natural and artificial light on the usability of the screen and the ‘competition' between ambient sound and the device's audio output.
1.3 Examples of good practice:
1.3.1 General
- Large, flat on/off switch requiring small degree of sustained pressure to operate, resistant to 'fluttering/flickering' pressure
- Colour differentiation of on/off switch from other buttons and switches
- 'Sleeping' device that activates at touch of any control
- Telephone/kiosk controls can be reached by wheelchair users.
1.3.2 Public Transport Terminals
- Screens at an optimal height for distance and close viewing
- Sound loud enough to overcome ambient noise but not painful.
1.3.3 Public Libraries:
- Adjustable screen orientation for proper ambient light
- Ear phones for audio.
2. Perception
2.1 The main purpose of most accessibility devices is to secure perception, i.e. the reception by the senses of a data stream.
2.2 Information designed for one sense only is not perceivable by those who lack that sense; this underlines the importance of multi modality (see Principle 2. of digital design).
2.3 Where there is no user control, speed of delivery is also critical to perception. The optimal speed will depend on the purpose; e.g., the destination of trains needs to be delivered more slowly than a general announcement on travel conditions.
2.4 Examples of good practice:
2.4.1 All systems:
- Create simultaneous but independent text, audio and graphical information
- Specify compatibility with (peripheral) accessibility devices (screen readers, hearing aids).
2.4.2 User Controlled Systems:
- Allow maximum customisation
- Default systems to optimal reception of text (size, font etc), audio (main purpose without embellishment) and graphics (main purpose without embellishment). The distinction between the main purpose and embellishment is the function of the information; e.g., what is classified as embellishment on a purely information site may be regarded as the main purpose on an artistic site.
2.4.3 Public Systems:
- Default to a rational, optimal delivery speed where customisation is not possible
3. Cognition
3.1 While a designer cannot have a direct effect on cognition, it is vital that it is made as simple as possible in such areas as:
- Directing the user's focus of interest through physical positioning in visual arrays; e.g., depending on context put the vital information at the top left or in the middle of a screen or page and put the most information at the beginning of a piece of audio.
- Making ranking clear; e.g., delivering the information in descending order of importance to the producer through visual arrangement or audio delivery
- Highlighting top priorities
- Defaulting systems to their simplest but allowing customisation for complexity.
3.2 The key concept in cognition is sharp focus on the required task. Designers may wish to embellish their systems with aesthetic and whimsical material but this should be 'defaulted out' so that the initial default is task-oriented.
3.3 Examples of Good Practice
- Clear transaction flow with a highlighted starting point
- Use of visual devices as well as Alphanumeric ranking to demonstrate priorities
- Reducing the size of metadata and peripheral information which refers to the information as a whole; e.g., information about a website, details of a television channel, source of audio publishing
- Delivering a simple audio stream as default
- Using graphics to complement (rather than comment on) text and vice versa
- Use language appropriate to the user.
4. Integration
4.1 Again, designers cannot have a direct effect on the user's ability to integrate a current information experience with his/her overall knowledge base but good design can assist this process through the intelligent use of links. Clearly, different people have different kinds of knowledge association and so nothing can be guaranteed.
4.2 Examples of good practice:
Point to:
- The oeuvre and school of a named artist/author/composer
- The preceding history of an event
- Similar data configurations
- Definitions and explanations
- Further data on the same subject.
5. Intent
5.1 It is easy to forget that the authorial intention of an information system may not be clear to the user; e.g., without clear direction a user may think that a sales site is simply an advertisement. As a designer it is important to remember that you are an agent of the author not the author.
5.2 Authorial intention should always be clearly stated at the user entry point; e.g., web home page, beginning of a television programme, synopsis of an article.
5.3 Alternative uses for an information system should be clearly stated, making it easy for the user to choose one course of action, revert to the starting point and choose another.
5.4 In terms of accessibility, an information system which presents artistic material may need to specify that it is non customisable whereas a system whose purpose is to sell goods should be as customisable as possible and not conceived as 'art'.
5.5 Humour is particularly difficult to convey in information systems that serve many people from many cultures. There are also people who have the graphic equivalent of illiteracy which means that picture captions are essential.
5.6. Examples of Good Practice:
- A web site with a clear mission statement, e.g. this is Hypo's on-line shopping service
- An art gallery site with a clear user specification, e.g. This site contains artistic material which the owners have made available on condition that the material cannot be customised
- This document can only be read and not edited.
- The following material is commercial promotion.
- A humorous cartoon with a text equivalent.
6. Navigation
6.1 There are two fundamental attributes in navigation:
- Knowing where you are; and
- Knowing how to get where you want to go.
6.2 Knowing where you are involves:
- Showing an indicator on a list or menu; or
- Identifying a stream of data being accessed.
6.3 Examples of good practice:
- Highlighting current function on a menu
- Using a web page or television channel identifier
- Providing simple, parallel, metadata for audio that cuts out all but the essential information.
6.4 Knowing how to get where you want to go can be achieved either spatially or taxonomically. Both of these strategies may require specialist input. Some spatial arrangements such as a list or a matrix may be obvious but more complex information may need more complex strategies. Taxonomy is not standard and depends on the purpose for which the information is being provided.
6.4.1 Spatial schemas should be simple and consistent.
Examples of Good Practice:
- A simple two-dimensional matrix of time and channel for Electronic Programme Guides
- A pie with different coloured segments (with a legend) for proportionality
- Chronological list of dates
- Alphabetical listing.
6.4.2 Taxonomical schemas should be consistent and simple. There is an obvious trade-off between the number of options or classes on the one hand and the number of layers to reach a final point on the other hand. Nonetheless, options or classes should be kept to a minimum with, in any case, no more than nine. It is possible and even desirable to use different terms e.g., technical and non-technical) to reach the same piece of information; and a particular piece of information may appear as a sub class in different classes. The definition and number of classes should not vary according to platform as this is inconsistent (e.g. different taxonomies for a phone and PC database from the same source).
Examples of good practice:
- A taxonomy of nine to accord with numeric keypads, supplemented by SMS for 'last mile' long lists
- A taxonomy of four to route telephone calls to a call centre
- Health information which can be accessed by professionals and patients using different terminology.
7. Interaction
7.1 As the division between non interactive (receiver) and interactive devices becomes ever more blurred, it is important for interactivity to be signposted and defined. Interactivity usually means one of three things:
- Choosing between options; e.g., camera angles in a sports broadcast
- Directly responding to an enquiry or submitting data within defined fields; e.g., answering a questionnaire
- Feeding data into a system in response to a general request; e.g., blogging.
The gap between the first and third of these options underlines the importance of specifying the nature of interactivity on offer.
7.2 Genuine interaction takes place when all users of an information system participate on equal terms (see 8. Creation below).
7.3 Examples of Good Practice
- A Television channel says: "You may choose from the following options using the red button"
- A Government web site says: "You may respond to the consultation questions but there is no option for adding topics"
- A telephone feedback line which says: "Your reply should be no more than 90 seconds; you will hear an (unrecorded) bleep every 15 seconds with two bleeps when you have 15 seconds to go).
8. Creation
8.1 This final attribute is added for completion. It requires appropriate authoring tools and is beyond the scope of this simple manual. All that can be said here is that if an information system exists to encourage creativity it must be conscious of the tools requirements of creators.
Chapter 2 - Generic Principles of Digital Design
Summary
Principles of digital Design for All in descending order of importance; the system should be:
- Fit for Purpose/Legally Compliant
- Multi Modal
- Device/Platform Independent
- Flexible/Customisable
- Defaulted to the simplest and most accessible settings
- Orientationally Explicit
- Robust
- Consistent
- Attributionally Transparent
- Authorially Specific.
Generic Explanations of Principles of Design For All
1. Fit for Purpose/Legally Compliant
1.1 The primary tool for establishing fitness for purpose is a generic user requirement, a statement in non technical terms of what need the system is required to fill. The generic user requirement should then be turned into a technical specification that meets all the needs of the requirement.
1.2 The major signposts for the user requirement will be the vision, mission and strategic statements of an organisation.
1.3 Information systems may be subject to a variety of legal requirements.
1.4 Examples. There will be very different requirements for:
- A public body legally required to serve all citizens
- A private club with a restricted and known membership
- An exhibition of visual art
- A wholesale enterprise.
2. Multi Modal
2.1 A multi modal system is one which simultaneously offers text, audio and graphics which can be accessed simultaneously but which convey the same essential information when they are singly accessed.
2.2 This concept is not uniformly helpful; there is a difference of effectiveness between:
- The description of a painting and the provision of an audio version of a text for a blind person
- The use of sub-titled audio or the provision of a musical score for deaf people.
Where there is a serious failure in the multi-modal approach, designers need to think about the concept of equivalence; i.e., trying to provide the end user with an experience that conveys as much as possible of the author's intention. This is a highly specialised area of work.
2.3 In making decisions about cost/benefit the considerations in 1. above are vital.
2.4 Examples:
- Sub-titled, signed and audio described television
- Icon/Pictograph support for text
3. Device/Platform Independent
3.1 Digital information should be generically designed so that it can be accessed on different platforms using different interfaces.
3.2 Systems should be platform and user interface customisable through the use of macros which automatically redesign pages in accordance with the output device.
3.3 The restriction to platforms and user interfaces limits accessibility.
3.4 Examples:
- Automated removal of large graphics from PC pages being downloaded into a mobile phone
- Maximum content volume to accord with minimum user interface capacity
- Multiple user interface manipulation including
-
- QWERTY keyboard
- SMS
- Numeric keypad
- Voice in
- Bifurcating switch (for physically disabled people).
4. Flexible/Customisable
4.1 Content should be separated from style and presentation so that the user can control the content.
4.2 Design should be as granular as possible to allow for the independent manipulation of different elements; e.g., foreground and background, text, size and font, the volume of different audio strands, the intensity of colour of different elements.
4.3 The degree of user freedom should reflect the considerations in 1. above. A novelist's rights might be more restrictive than a public sector document.
4.4 The ability to customise should not be open-ended as this can disorient users; those who require abnormal customisation usually have access to peripheral user interface devices such as special screen magnification software.
4.5 The concept of granularity and the way in which content is provided should be complemented by progressive enhancement in the applications that are used to access it; e.g., in web access html should be foundational whereas Flash should enhance the experience.
4.6 Examples:
- Customisable:
-
- Print size, font, kerning, leading, justification
- Colour foreground/background
- Simplifiable simultaneous outputs, e.g.:
-
- Text on pictures
- Multi track audio
- Removing graphics to magnify text without losing page cohesion
- Simplifying text through parsing machines.
5. Defaulted to the simplest and most accessible settings
5.1 The default settings should be set to the simplest and most accessible because it is easier for non disabled people to switch features off than disabled people to switch them on.
5.2 This in turn means that accessibility and simplification tools such as the capacity for synthetic speech production, adjustable print size and font and colour intensity should be incorporated in the original design and not retro-engineered.
5.3 Although this may seem counter intuitive, systems should be programmable, particularly so that unwanted features can be put into background.
5.4 Examples:
- A blind person cannot independently switch speech output on
- It is easier for an expert to amplify than for a beginner to simplify.
- Users may only want five specific television channels plus a button for "other"
- A user may want to simplify mobile phone menus and put functions into 'background", e.g.:
- A blind person may wish temporarily to disable all the camera features
- A person with low vision may wish to limit the number of items in a menu
- A user may simply want to use the telephone to make and receive calls.
6. Orientationally Explicit
6.1 Users need to know where they are within a system so that they can choose to stay where they are or know the most effective route for finding something else.
6.2 This requires clear status information and signposting to other sources.
6.3 Examples:
- Clear internet status lines and links to other parts of the site, including "Home" and "Back"
- Television/radio channel status indicators and simple programme guides.
7. Robust
7.1 A system should be able to survive incorrect user interface input by reverting to its previous status.
7.2 If 7.1 is not possible, any output following false input should clearly advise the user on how to revert or proceed.
8. Consistent
8.1 The need for consistency applies to:
- User interface input
- Terminology
- Taxonomy
- Navigation/Orientation/Sequencing
8.2 User interface input currently varies between devices but this should be kept to a minimum. The best starting point is to design for a system with the simplest user interface, e.g.:
- Numbers 0-9
- Back
- Other
- Enter (where there are more than 10 options).
8.3 Terminology should be consistent and as jargon free as possible.
8.4 Taxonomy should optimise between the number of options and the number of layers. Strictly speaking, a system with a numeric keypad should limit the number of options in any taxonomical system to 9 plus "other". Taxonomy should not vary between user interfaces.
8.5 Navigation, orienting and sequencing of data elements should be as consistent as possible.
8.6 Examples:
- The standard layout for numeric keypads should be used
- Different terms should not be used for the same concept, e.g.:
- Enter, execute, authorise, transact, go!
- Log-in, log on, register, sign up, sign in, sign on
- Taxonomy should not change according to user interface, e.g. if an electronic programme guide is designed with nine programme categories to accord with remote controller access, the same content should not be allocated to more categories for a web device
- Major elements such as time, date, links, channel indicator, should appear in the same place in layout.
9. Attributionally Transparent
9.1 Users should know the status of the information they access as far as the supplier can warrant.
9.2 Examples:
- Genre
- Authorship
- Self published, published, peer reviewed
- Censored
- Commercial, public sector
- Public domain free/for sale.
10. Authorially specific
10.1 Authors should make their expectations of consumers and users clear. This is particularly important for public sector information systems.
10.2 Examples:
- Subscribing is compulsory
- Consultation is limited to answering given questions/supply additional information.
Chapter 3 - Platform Migration
The following are key points in descending order of importance in designing digital information for more than one platform:
Summary
- Unified control system
- Granular composition
- Macros for Output Capacity
- Quality output check
- Specify options
1. Unified control system
1.1 Any digital information system intended for more than one platform or user interface should have a common control system.
1.2 Examples of Good Practice:
- Use the lowest common control set; this is usually the numeric keypad with two or three additional, preferably programmable controls; conversely avoid PC functions such as tab.
2. Granular Composition
2.1 Adapting information arrays while preserving authorial intention is made much easier with granular design where the user can alter elements without interfering with the initial author product. When the user has finished the system can default back to the authors' intention.
2.2 No elements which are part of a compilation should be 'bound' or 'alloyed' to other elements so that they cannot be separated (the difference between blue and yellow painted stripes and blue and yellow paint poured into a single pot).
2.3 Although granular composition is a relatively common practice in web design and is an increasingly common aspect of television and DVD composition, music is the odd exception. It is created in multiple tracks and then 'bound' into fewer tracks when it should be delivered unbound with each track subject to separate volume control for on/off and volume control.
2.4 Examples of Good Practice:
- Deliver multi track sound and not stereo or mono
- Retain text in text files
- Superimpose layers of graphical material.
3. Macros for Output Capacity
3.1 The output capacity of information systems varies, e.g. the capacity of a PC screen and an integrated mobile phone screen; the difference between the resolution of an analogue and a high definition television screen; the difference between a hi-fi quadraphonic system and an ear-piece only radio.
3.2 It is important to define a default setting for optimum access, bearing in mind the primary user interface; e.g., a layout primarily designed for a mobile phone may require amplification macros for PC use. Conversely, a layout primarily designed for a PC may need simplification macros for mobile phone use.
3.3 The worst possible course of action is to design one compromise layout supposed to fit all user interfaces; e.g., a linear monochrome text presentation that is too dense for a mobile phone and does not take advantage of the space provided by a computer screen.
3.4 Examples of Good Practice:
- Design the simplest possible expression of authorial intention for the smallest output device; then provide for progressive amplification
- Design the richest possible expression of authorial intention and provide macros for progressively simplified versions.
4. Quality Output Check
4.1 Output quality varies between different user interfaces. Output quality should always be checked on the highest and lowest quality potential outputs.
4.2 Examples of Good Practice:
- Show PC content on mobile screen and vice versa
- Play music through maximum capacity speakers and small ear piece.
5. Specify Option
5.1 All progressive data element simplification and amplification options should be shown on all user interfaces, so that users can customise the amount of information to fit their device and so that they can also vary the amount of information reaching the device.
5.2 Examples of Good Practice:
- Exclude images that are more than a given size (a x b)
- Exclude standard metadata features such as descriptions of the service that is being provided.
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[1] Carey, Kevin, Gracia, Rosaria, Power, Chris, Petrie, Helen & Carmien, Stefan: Determining Accessibility Needs through User Goals