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Usability and Accessibility Lecture 5 – 02/03/10. Heuristics as a design approach. Setting the scene. “Rehabilitation Robotics in Europe” c.1997 EU funded many projects under TIDE initiative LOTS of money!!! Projects generally major disasters Let’s see why ….

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Usability and Accessibility Lecture 5 – 02/03/10

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Usability and AccessibilityLecture 5 – 02/03/10

Heuristics as a design approach

Setting the scene

  • “Rehabilitation Robotics in Europe” c.1997

  • EU funded many projects under TIDE initiative

  • LOTS of money!!!

  • Projects generally major disasters

  • Let’s see why…

An example – The EPI-RAID robot

EPI-RAID failed because…

  • No in-built market to sell to

    • Had to sell on its own merits

  • Too expensive

    • (~5000000DKK)

  • Overtaken by new technology

    • Internet

  • Not enough consideration of what it was to be used for

    • Too much focus on the technology

Needed a user-centred design approach!


Can we use Nielsen’s heuristic in the design process?

  • i.e. not just for post-hoc testing

Reminder: The fundamental stages of design

  • STAGE 1 - define the problem

  • STAGE 2 - develop a solution

  • STAGE 3 - evaluate the solution

user wants/needs system requirements

develop a usable system for “all” users

verify/validate for all users

The fundamentals of interaction

  • Card, Moran and Newell (1983 – “The Psychology of Human-Computer Interaction”) proposed that actions could be described by:

Putting heuristics into the design process



  • STAGE 1 - Problem specification

  • STAGE 2a - Visibility of system status


  • STAGE 2b - Match between system and real world


  • STAGE 2c - User freedom and control


  • STAGE 3 - Evaluation/verification







Also known as the 5-level model

See Keates and Clarkson “Countering design exclusion”


From: Keates & Clarkson “Countering design exclusion”

The IRVIS (Interactive Robotic Visual Inspection System) prototype

Questions of interest

  • Question 1: Is the robot under-specified or fundamentally “wrong”?

  • Question 2: Can we make it usable?

  • Question 3: Can we make it accessible?

Level 1 - Problem requirements

  • AIM 1: What are the system requirements?

  • AIM 2: Why did the original interface fail?

  • ASSESSMENT: Verify problem definition







Level 1 – Understanding the system requirements

  • What are the system requirements?

    • Understand manual process

    • User observations

  • Why did the original interface fail?

The original interface

Level 1 - Problem specification (cont.)

  • Inspection process requires:

    • Translation

    • Rotation

    • Tilting

    • Zooming

    • Focusing

Developing a solution: the “Variable Fidelity Prototype”

Level 2 - Output to user – “Visibility of system status”

Level 3 - User mental model – “Match between system and real world”

Level 4 - Input from user – “User freedom and control”

Level 5 – Verifying functional and usability attributes

Level 5 - Social attributes

  • The design of a new interface has shown significantly increased usability

  • Qualitative user feedback extremely favourable

  • The final interface also showed improved usability for able-bodied users

  • Costly robot re-build avoided

Features of the 5-level model

  • Iterative approach, with user trials and evaluation at each level

  • Addresses each stage of the interaction process explicitly

  • Guidelines can be incorporated where applicable

  • Clear focus on usability

Improving the 5-level model…

  • Will be seen a little later…


  • Usability and design are closely intertwined

  • Usability needs to consider design perspectives

  • Usability methods used need to complement design process and stage of development lifecycle

Introducing “inclusive design”

The need for inclusive design - a “typical” user

The need for inclusive design - the bigger picture

What is a good/inclusive interface?

  • Acceptable by the intended user group

    Need to define:

  • What is the intendedusergroup?

  • What is acceptable?

Who are the intended users?

Typical user stereotypes

  • The “disabled”

  • The “elderly”

  • The “personinthestreet”

  • The “customer”

Designing inclusively = design for the disabled (?)

  • Need to adopt inclusive design arises because user capabilities ≠ product demands

  • Thus users with limited or impaired capabilities need a more accessible version to be designed

  • User group most commonly (stereotypically) associated with limited or impaired capabilities is people with disabilities

  • Ergo – designing inclusively is really designing for the disabled



Least capable

Least capable

Most capable

Most capable

Inclusive design philosophies



Examples of the different approaches



AN Other Mouse

Approaches to “designing for the widest possible range of users”

  • Universal Design

  • Design for All

  • Universal Access

  • Inclusive Design

  • Countering Design Exclusion

  • Design for disability

Universal Design

  • For a long time the most famous “inclusive design” approach

  • Very popular in Japan and USA

  • Strong association with architectural design

    • Buildings access

  • Not big in Europe

    • “Guiding principles” seen as too rigid and too deeply associated with its US heritage

The 7 guiding principles of Universal Design

  • 1 - Equitable use

    • The design must be useful and marketable to people with diverse abilities

  • 2 - Flexibility in use

    • The design accommodates a wide range of individual preferences and abilities

  • 3 - Simple and intuitive

    • Use of the design is easy to understand, regardless of the user’s experience, knowledge, language skills or current concentration level

  • 4 - Perceptible information

    • The design communicates necessary information effectively to the user, regardless of the ambient conditions or the user’s sensory abilities

The 7 guiding principles of Universal Design

  • 5 –Tolerance for error

    • The design minimises hazards and the adverse consequences of accidental or unintended actions

  • 6 –Low physical effort

    • The design can be used efficiently and comfortably and with a minimum of fatigue

  • 7 –Size and space and approach for use

    • Appropriate size and space is provided for approach, reach, manipulation and use regardless of user’s body size, posture or mobility

Other approaches to designing for the most possible users

  • Design for All

    • An older approach, very popular at one time

  • Inclusive design

    • Popular in Europe

    • More flexible approach than Universal Design

  • Universal Access

    • “Inclusive design for HCI”

  • Countering design exclusion

    • Developed by Keates and Clarkson (see book of same name)

Design for All(?)

  • Synonymous with “one product for all” (note – incorrectly)

    • Not really a feasible goal (see first lecture)

  • EU eEurope initiative defines DfA as:

    • “…designing mainstream products and services to be accessible by as broad a range of users as possible.”

Defining “inclusive design” (source: Keates “Designing for accessibility”)

  • UK Department of Trade and Industry:

    • Inclusive design is a process whereby “…designers ensure that their products and services address the needs of the widest possible audience.”

  • RSA (Royal Society for the Encouragement of Arts, Manufacture and Commerce):

    • Inclusive design is “… about ensuring that environments, products, services and interfaces work for people of all ages and abilities.”

  • UK Design Council:

    • “Inclusive design is not a new genre of design, nor a separate specialism, but an approach to design in general and an element of business strategy that seeks to ensure that mainstream products, services and environments are accessible to the largest number of people.”

Countering design exclusion (CDE)

  • Defined in BS7000 Part 6:

    • Design exclusion is the “…inability to use a product, service or facility, most commonly because the needs of people who experience motor, sensory and cognitive impairments have not been taken into account during the design process.”

CDE philosophy

  • If you can identify who cannot use the product and why, then you know what to focus on fixing

  • More practical approach than “design for a wide variety of users (but we’re not going to tell you who and how many) in a wide variety of circumstances (ditto)”







What is exclusion?










Where does exclusion come from?

Where does design exclusion come from?

“Designers design for themselves”

Examples to follow…

Design trade-offs…

Limits to inclusion - trade-offs

An example compromise




How are people excluded?

People are excluded based on their capabilities (DFS)

•locomotion • hearing

•reach and stretch • vision


•intellectual functioning • communication

and the demands made by the product

Quantifying exclusion

  • We will look at how to measure and report exclusion in later lectures

  • You will see examples in the reading material for this week


Where to look for prevalence data

  • The charities

    • RNIB, NFB, AFB, RNID, etc.

  • Lots of really useful information and data

    • e.g.

  • Great info about causes and symptoms

  • Question: Are these unbiased sources of data?

Charities and prevalence data

  • Difficult to tell how unbiased data is

  • Best sites cite independent studies

  • Others mention figures with no (or dubious) attributions

  • Need to treat such data cautiously

  • Better to rely on “official” sources, e.g. government bodies

Defining “disability” - WHO

Prevalence of “disability” in US (source: US Census Bureau 1999-2004 American Community Survey)

Multiple capability losses in US (source: US Census Bureau 1999-2004 American Community Survey)

We will look at the implications of multiple impairments later…

UK Disability Follow-Up Survey

  • Follow-up to 1996/7 Family Resources Survey

  • 7500 respondents

  • 13 separate capabilities identified as important to independent living

  • 7 relevant for product design:

    • Locomotion

    • Reach and stretch

    • Dexterity

    • Seeing

    • Hearing

    • Communication

    • Intellectual Functioning

We will look a lot more closely

at this next week

Mapping to interaction models

  • Motor = locomotion, reach & stretch, dexterity

  • Sensory = seeing, hearing

  • Cognitive = communication, intellectual functioning

UK Disability Follow-Up Survey (Grundy et al, 1999)

Disability Follow-up summary

  • 8,582,200 adults in GB have a disability

    • 17% of the total population (1 in 6)

      Of these:

  • 34% had mild impairments

  • 45% had moderate impairments

  • 21% percent had severe impairments

  • 49% had more than one impairment type

  • 48% of disabled population is over 65

  • 29% of disabled population is over 75

Importance of ageing

  • Population is getting older

UK population



It’s not just blindness

  • Traditionally most “accessibility” approaches for HCI have focused on blindness


  • Very “visible” difficulty

  • Very easy to simulate

    • Switch off the monitor

  • Very effective lobbying group

WCAG 1.0 and 2.0

Look through the WCAG guidelines:

  • How many address vision issues (specifically blindness)?

  • How many address motor issues?

  • How many address cognitive issues?

  • How many address hearing issues?

Answer: Most

Answer: Some

Answer: Few

Answer: Few

Problem with focus on blindness

From DFS:

  • 1.93 million people have vision impairment

  • Only 20% of those are “blind”

    • Need screen readers, etc.

  • 80% are “low vision”

    • Need screen magnification

  • c.f. 2.9 million people with hearing impairments

  • …and 6.7 million with motor impairments

Sensory impairments – Classes of impairment

  • Vision

    • Blindness – cannot see “at all”

    • Low vision – cannot see well

    • Colour blindness – cannot see all of the colour spectrum

  • Hearing/auditory

    • Deafness – cannot hear “at all”

    • Low hearing – cannot hear well

Cognitive impairments – Classes of impairment

  • Poor long-term memory

  • Poor short-term memory

  • Dementia – e.g. Alzheimer’s

  • Language “deficits” – e.g. below chronological reading age

  • Reading difficulties – e.g. dyslexia

  • Behavioural/attentional difficulties – e.g. ADD, ADHD

Motor impairments – Classes of impairment

  • Restricted range of motion

  • Tremor

  • Spasm

  • Poor co-ordination

  • Limited strength

  • Poor fine movement

  • Poor ballistic movement


Exercise – part 1

  • Each group will be assigned a type of website

    • Group 1 – car rental sites (e.g. Avis, hertz, alamo, budget)

    • Group 2 – airline flight booking sites (e.g. flysas, virginatlantic, ba, sterling)

    • Group 3 – travel insurance sites (e.g. columbusdirect)

    • Group 4 – luggage (e.g. tumi)

    • Group 5 – clothing (e.g. versace, lacoste)

  • You must look at a minimum of 3 sites

  • For each website, use CynthiaSays ( to examine the reported accessibility of each site (WCAG Priority 1, 2 & 3)

Exercise – part 2

  • Use Nielsen’s heuristics from last week’s exercises to estimate the usability of each site

  • Question: Is there any relationship (correlation) between the overall usability and accessibility of the sites (as measured here)?

  • Prepare a 5 minutes presentation for Friday morning with your answer to the above question

  • No report needed for this exercise!

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