HCI guidelines - use and misuse

Susan Turner

Now and next in MSD...

This week - guidelinesweek 10 - case study & exam questionweek 11 - your turnresearch either

HCI issues in the design & evaluation of virtual reality

HCI issues in the design & evaluation of small mobile devices

Today’s lecture

Using guidelines and standards sensibly

Guidelines exerciseGuidelines for universal access

Guidelines and standards

Guidelines general purpose ‘rules’ in HCI texts and

websitesmost useful when include explanatory text

in-house and proprietary style guidesStandards

have formal authority

2.0/13 + Consistent WordingFor displayed data and labels, choose words carefully andthen use them consistently.

Example

(Good) | Record A Change | | Record B Change | |Record C Change |

(Bad) | Update of Record A | | Record B Maintenance | |Change in Record C |

Example

As a negative example, the word "screen" should not beused to mean "display frame" in one place, and "menuselection option" in another.

Comment

Consistent word usage is particularly important fortechnical terms. Standard terminology should be definedand documented in a glossary for reference by interfacedesigners as well as by users.

Reference

BB 1.2.2 3.7.2 EG 3.4.5 4.2.13 Pakin Wray 1982FromSmith & Mosier(1986)

ftp://archive.cis.ohio-state.edu/pub/hci/Guidelines/guidelines

Shneiderman’s 8 golden rules of dialogue design

Strive for consistencyEnable frequent users to use shortcutsOffer informative feedbackDesign dialogs to yield closureOffer simple error handlingPermit easy reversal of actions Support internal locus of controlReduce short-term memory load

Hix and Hartson’s guidelines

1. User centered design 8. Give a task-based mental model

2. Know the user 9. Be consistent

3. Involve the user 10. Keep it simple

4. Prevent user errors 11. Design for memory limitations

5. Optimize user operations 12. Use recognition rather thanrecall

6. Keep control with the user 13. Use cognitive directness

7. Help the user to get started 14. Draw on real-world analogies

Hix and Hartson (2)

15. Use informative feedback 22. Use modes cautiously

16. Give status indicators 23. Make user actions reversible

17. Use user--centered wording 24. Get attention judiciously

18. Use non-threatening wording 25. Maintain display inertia

19. Use specific, constructiveadvice

26. Organize screen to managecomplexity

20. Make the system take theblame

27. Accommodate individualdifferences

21. Do not anthropomorphise (Hix and Hartson, DevelopingUser Interfaces, Wiley, 1993)

Apple guidelines for shortcuts

Guidelines for web design

www-3.ibm.com/ibm/easy/eou_ext.nsf/Publish/572

try also www.useit.com (Jakob Nielsen’s site)

Using Guidelines

guidelines often conflict in specific instances helps to understand the underlying reasoning consider the requirements of the situation and

decide which aspects are most important

basis of ‘heuristic evaluation’ (more in later lecture)

a collection of guidelines linkswww.ida.liu.se/~miker/hci/guidelines.html

Standards

Set by (inter)national standards bodies, but often industry driven International Standards Organisation (ISO) International Telegraph and Telephone

Consultative Committee (CCITT) British Standards Institute (BSI) American National Standards Institute (ANSI)

prescriptive, rather than advisory

For example

ISO 9241 Ergonomics for Office Work with Visual Display Terminals

ISO 14915 Ergonomics for Multimedia User Interface Design

BSEN ISO 13407 ‘Human Centred Design for Interactive Systems’

conformance usually by process not product

also European directives (e.g.90/270/EEC)

ISO 9241

General introduction Guidance on task

requirements VDU requirements Keyboard requirements Workstation layout and

postural requirements Environmental

requirements Display requirements with

reflections Requirements for

displayed colours

Requirements for non-keyboard input devices

Dialogue principles Guidance on usability

specification and measures Presentation of information User guidance Menu dialogues Command dialogues Direct manipulation

dialogues Form-filling dialogues

3.1. Structuring into levels and menus (overall structure)

Menu structures should reflect user expectations and facilitate the user’s ability to findand to select menu options relevant for the task. In order to increase the probability ofmeeting this objective, the following conditional requirements and recommendationsshall be evaluated...

3.11. Conventional categories

If options can be arranged into conventional or natural groups known to the users,options shall be organised into levels and menus consistent with that order.

Example: Grouping foods into meats, vegetables, fruits

Dialogue principle: User expectations

Conformance: applicability - documented evidence, analytical evaluation or empirical evaluation.

compliance - observation

ISO 9241 example

European directive of 29.5.90

minimum health & safety requirements for employees who work with display screens

wide exceptionsemployers’ obligations

In summary

Guidelines can be useful, but need thought in their application

Be aware of HCI standards

Designing for universal use

Universal design

“Universal design for telecommunications and information systems means designing products which can be effectively and efficiently used by people with a wide range of abilities or in a wide range of situations.”

Universal Access Project, University of Wisconsin, 1995

need to be aware as users as designers and implementers as support engineers

Justification for universal design

Legal and ethical rights e.g. Disability Discrimination Act (UK)

Contribution to a more open society move away from ‘disability products’

Broader market expansion of technology into new domains and for new

users aging population

Broader application area not just people with special needs, but ordinary people in

special circumstances (low light, wearing gloves, noise…)

Aging computer users...

Age Group Proportion of People with Disabilities

0 - 21 10%

22 - 44 14.9%

45 - 54 24.5%

55 - 64 36.3%

65 - 79 47.3%

80+ 71.5%

Relevant human abilities & design

Think about abilities, not types of people vision hearing cognition mobility and dexterity

designing for the elderly and children some or all of these may be relevant

design proactively avoid inadvertent exclusion design to be accessible, usable and and acceptable

Ways of widening access

New features for hardware and operating systems features universally available for compliant applications

Assistive technologies enhance accessibility, but must be moved between computers cost issues

Specialised applications e.g. browsers which read pages but people with special needs often work alongside others with

standard applications

Usability features for mainstream applications e.g. customisable colours to maximise contrast & therefore

readability

Some assistive technologies

Screen enlargers like a magnifying glass can set and move area of focus

Screen reviewers or readers make text available as speech or as Braille graphics only included if alternative text provided

Voice input not just text, but also as substitute for mouse/keyboard

control On-screen keyboards

select keys using alternative input devices keyboard filters

compensate for tremor, erratic motion, slow response time...

Did you know?

Windows Accessibility Options (under control panel)

keyboard sound

visual warnings & captions for sounds

display high contrast options

mouse

A general approach

Requirements/specification include people with special needs in requirements analysis and

testing of existing systems consider whether new features affect users with special needs

(positively or negatively) and note this in specification Design

take account of guidelines Testing

include evaluation against guidelines include special needs users in usability testing and beta tests

Implementation make sure programming team are aware of guidelines if prioritising bugs for fixing, consider that some may have

disproportionately more impact on users with special needs

Basic principles of accessible design

Flexibility customisable user interface to accommodate

preferencese.g. font size, menu arrangement

Choice of input and output methods e.g. keyboard as well as mouse redundant combinations of sound, graphics and

text

Consistency within and between applications

Prioritise

Number of users give higher priority to features that affect

more users e.g. more people view documents than author

them

Frequency of useNecessity of use

give priority to features which are central to the product

Some useful links

www.microsoft.com/enable* detailed guidelines for Microsoft applications and

more general advice

www.abilitynet.co.uk general advice on computing and related

technologies for people with special needs

www.cast.org.uk/bobby web site checking service - also provides guidelines

*acknowledgment: much of previous material derived from here

A specific example - designing for low vision (1)

Key principles - redundancy and flexibility Keep to standard menu and dialogue box layouts

helps to memorise position of options

Provide keyboard alternatives Use audio ‘tooltips’ Supplement visual prompts with audible signals

(or vibration or tactile output, such as to Braille display)

Use shading and patterns for visual items to supplement colour

Designing for low vision (2)

Use characters of at least 7.5 mm or 16 point on screen Use San Serif font for labels, etc., Serif font for text Generally, dark letters on light background are

preferable Allow messages to remain on the screen until dismissed

by the user Allow text to be enlarged and colours, contrast and

brightness to be adjusted

Provide documentation in media which will allow users to listen to it

In summary

Be aware that guidelines and accesibility aids exist

Wherever possible, design for inclusion rather than exclusion