Transcript Software for Metrology

Formalising usability as part of
ISO standards
Nigel Bevan
[email protected]
www.usability.serco.com
www.usabilitynet.org
Serco Usability Services
UK
©Serco Reproduction permitted provided the source is acknowledged
1
Topics
 What is usability?
 Definitions of usability? ISO 9126-1 and ISO 9241-11
 Specifying usability as quality in use: ISO 9126-4, the
Common Industry Format and ISO 25030
 Usability of everyday products: ISO 20282
 User interface usability: ISO 9241
 User centred design process: ISO 13407
 Usability capability: ISO TR 18529
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What is usability?
 what do you think usability is ......?
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IBM
 “IBM's focus on ease of use has led to technology
breakthroughs and advances in design research”
 “For developers and manufacturers, the advantages of
creating usable products far outweigh the costs”
 “Every dollar invested in ease of use returns $10 to
$100”
http://www.ibm.com/ibm/easy/
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4
Microsoft
 “The Usability Group is an integral part of the product
design process at Microsoft”


Over 120 usability engineers
Over 25 usability labs
http://www.microsoft.com/usability/
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Why is usability important?
 Focus on user and organisational needs


reduce development times
less training and support and documentation is required
 Improve productivity

simpler interface, fewer user errors
 Improve the competitive edge



increasing expectations for ease of use
increasing usability of competitive products
high profile of usability in advertising
 Improve the quality of life


less stress, users are more satisfied
lower staff turnover
 Health and safety legislation

European Directive on Display Screen Equipment
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Case study: Hewlett Packard
User-centred design methods were applied to redesign
software used for identifying network problems:
time to finish task
problems identified
average length of call
size of manual
people needing the manual
user satisfaction rating
Old
9.4 min
16%
30 min
25 pages
53%
3.5
New
4.1 min
78%
10 min
4 pages
3%
6.8
In addition to the benefits to customers, HP recovered their
costs in 18 months
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ISO/IEC 9126 Software Product Quality Model
functionality
reliability
accuracy
suitability
interoperability
security
maturity
fault tolerance
recoverability
availability
usability
efficiency
understandability
learnability
operability
time behaviour
resource
utilisation
maintainabili
ty
portability
analysability
changeability
stability
testability
adaptability
installability
co-existence
replaceability
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ISO/IEC 9126-1 Definitions
 Functionality

The capability of the software product to provide functions which meet stated
and implied needs when the software is used under specified conditions.
 Reliability

The capability of the software product to maintain a specified level of
performance when used under specified conditions
 Usability

The capability of the software product to be understood, learned, used and
attractive to the user, when used under specified conditions.
 Efficiency

The capability of the software product to provide appropriate performance,
relative to the amount of resources used, under stated conditions.
 Maintainability

The capability of the software product to be modified. Modifications may
include corrections, improvements or adaptation of the software to changes in
environment, and in requirements and functional specifications.
 Portability

The capability ©Serco
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software
product to be transferred from one environment to
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ISO 9241-11 Guidance on Usability
Usability : The extent to which a product can
be used by specified users to achieve
specified goals with effectiveness, efficiency
and satisfaction in a specified context of
use.
Effectiveness : The accuracy and
completeness with which users achieve
specified goals.
Efficiency: The resources expended in
relation to the accuracy and completeness
with which users achieve goals.
Satisfaction : The comfort and acceptability
of use.
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ISO/IEC 9126-1 Software Product Quality Model
quality in use
functionality
reliability
accuracy
suitability
interoperability
security
maturity
fault tolerance
recoverability
availability
usability
efficiency
understandability
learnability
operability
attractiveness
time behaviour
resource
utilisation
maintainability
portability
analysability
changeability
stability
testability
adaptability
installability
co-existence
replaceability
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11
Quality in Use
ISO/IEC 9126-1 (2001) Software Engineering Product quality - Part 1: Quality model
quality in use
the capability of the software product to enable
specified users to achieve specified goals with
effectiveness, productivity, safety and satisfaction
in specified contexts of use


Quality in use is the user’s view of the quality of a system
containing software, and is measured in terms of the result of
using the software, rather than properties of the software
itself
Quality in use measures the combined effect of ease of use,
functionality, efficiency and reliability.
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Approaches to achieving usability
organisational
capability
process quality
product quality
quality in use
effect of the
product
life cycle
processes
development
process
product
usability
capability
user centred
process
interface and
interaction
ISOTR 18529
ISO 13407
ISO 9241 parts 10, 12-17
ISO/IEC 9126-2/3
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usability in
context
ISO 9241-11
ISO 14598-1
ISO/IEC 9126-1
ISO/IEC 9126-4
ISO 20282-2
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Approaches to achieving usability
1 Design for quality in use


ISO 9241-11, ISO 9126-4: effectiveness, efficiency, (safety),
satisfaction
ISO 20282-2 Usability of everyday products
2 Design the user interface

ISO 9241 parts 12 to 17 Ergonomic principles
3 Use user-centred methods in development

ISO 13407 Human centred design processes
4 Establish organisational processes

ISO TR 18529 Human-centred lifecycle process descriptions
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What can be specified and measured?
requirements
requirements
product
evaluation
Quality in use
metrics
ISO/IEC 9126-4
User
requirements
Deliver
Test user goal
External
usability metrics
ISO/IEC 9126-2
Functional
requirements
Prototype
Internal
usability metrics
ISO/IEC 9126-3
Detailed
specification
Code
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Test user function
inspection
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1. Design for quality in use
Usability/quality in use measures:
 Effectiveness and efficiency

MUSiC Performance Measurement Method
http://www.usability.serco.com/publs.html
 Satisfaction

SUMI questionnaire
www.ucc.ie/hfrg/questionnaires/sumi
 Reporting usability


Common industry format for usability test results
includes intended context of use and actual context of
evaluation
www.nist.gov/iusr
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ISO/IEC CD 25030: Software quality requirements
and evaluation – Quality requirements
 Requirements can be categorised as:



functional requirements
quality requirements
other non-functional requirements
 Software quality requirements are categorised using the
ISO/IEC 9126-1 software quality model into
requirements for:



quality in use (the effectiveness, productivity, safety and
satisfaction with the software applied in its context of use)
external quality (the behaviour of the finished software product)
internal quality (static properties during development, such as
adherence to coding standards, and meeting size and
complexity thresholds)
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Requirements life cycle model
Definition
Formalisation
Evaluation
Functional requirements
Quality requirements
Developed system
Quality in use
Stated requirements
Stakeholder
needs
Measurable requirements
Measured quality
External quality
Stated requirements
Measurable requirements
Measured quality
Internal quality
Stated requirements
Measurable requirements
Measured quality
Other non-functional requirements
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Quality requirements specification
 Define quality requirements

Identify stakeholders
 end
users, developers, producers, trainers, maintainers, disposers,
acquirer, supplier organisations and regulatory bodies

Elicit requirements from stakeholders
 Quality




in use, External and Internal Quality
Analyse the set of requirements
Resolve problems
Confirm requirements
Record requirements
 Formalise quality requirements



Specify target values for measures
Demonstrate traceability
Maintain requirements
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Elicit requirements from stakeholders
 Include the needs, wants, desires, expectations and
perceived constraints
 Identify requirements



Quality in use
External
Internal
 Identify constraints
 Define scenarios of use
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Quality in use
Extent to which a product used by specified users meets
their needs to achieve specified goals with effectiveness,
productivity and satisfaction in specified contexts of use
 Effectiveness: accuracy and completeness
 Productivity: the resources expended by users in relation
to the effectiveness achieved
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Why is quality in use important?
 It is about meeting business and user needs



Effectiveness: success in achieving goals
Productivity: staff time
Satisfaction: willingness to use the system
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Quality in use: context of Use
 The usability of a product is affected not only by
the features of the product itself but also by its
Context of Use
 Context is the characteristics of:




the users of the product
the tasks they carry out
the technical, organisational
and physical environment
in which the product is
used
the date and time when the
product is being used
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Example: A bank ATM
Context description:
 The users
 The user characteristics
 The tasks users perform
 The technical environment
(hardware and software to
support system)
 The physical environment
 The social or organisational environment
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24
New design features to meet contextual
needs
 Recess for wheelchair access.
 Speech output for visually
impaired users.
 Customisation features for
rapid access.
 Finger print for identification.
 Visor appears during sunny weather.
 Buttons light during darkness.
 Alarm button for security alert.
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Efficiency: mean transaction times
3
2.5
2
Old sy stem
Minutes 1.5
New sy stem
1
0.5
0
Depositing
Cash
Withdrawing
Cash
Depositing
Cheques
Withdrawing
Cheques
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User satisfaction: SUMI questionnaire
60
50
40
30
New System
20
Old System
10
0
Global
Efficiency
Affect
Helpfulness Control
Learnability
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The danger of not setting quality in use
requirements
 New software for issuing UK passports




Installed in passport issuing offices
Took operators twice as long
Caused delays of up to 3 months in obtaining a passport
Huge cost of additional clerical staff
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Example of quality in use requirements
 User performance

“all data entry clerks will be able to complete the task with at
least 95% accuracy in under 10 minutes”
 User satisfaction

“the mean score on the SUMI scale will be greater than 50” More
information on quality in use requirements
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Common Industry Format usability tests
 NIST initiative
 National Institute of Standards and Technology
 Objective: raise the profile of usability in procurement
 Suppliers provide standard test reports to purchasers
 Suppliers include:
 IBM, Microsoft, HP, Sun, Kodak, Oracle, Compaq
 Purchasers include:
 Boeing, Northwest Mutual Life, State Farm Insurance, Fidelity
 Reports provided in confidence
 Could permit comparisons
 Agreed as US standard ANSI/NCITS 354, to be submitted to ISO
http://www.nist.gov/iusr
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Report format - technical
 Test objectives
 Participants



Total number and user groups
Key characteristics and capabilities expected
How selected: with the key characteristics and capabilities?
 Context of evaluation



Task scenarios and task data used
Any performance criteria used
Physical and computer environment
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Report format - results
 Effectiveness


% completely and correctly achieving their goals
Separate data where assistance was given
 Efficiency


Mean time taken to complete the task
Standard deviation (and standard error)
 Satisfaction

Optional: own scales or standard questionnaire
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ISO 20282: Usability of everyday products
Part 1: Universal user profile
Design should take account of
 Strength
and Biomechanical Abilities
 Handedness
 Body Dimensions.
 Visual Abilities.
 Auditory Abilities
 Cognitive Abilities
 Language and literacy
 Culture
 Age
 Gender
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33
ISO WD 20282-2: Test method
 A summative test method for measuring usability based on



ISO 9241-11 (Guidance on usability)
ISO 9126-4 (Quality in use metrics)
Common Industry Format for usability test reports
 Identify intended context of use and user groups
 Measures



Success rate (ease of operation)
Task time (efficiency)
Satisfaction scale (being developed)
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34
Approaches to achieving usability
organisational
capability
process quality
product quality
quality in use
effect of the
product
life cycle
processes
development
process
product
usability
capability
user centred
process
interface and
interaction
ISOTR 18529
ISO 13407
ISO 9241 parts 10, 12-17
ISO/IEC 9126-2/3
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usability in
context
ISO 9241-11
ISO 14598-1
ISO/IEC 9126-1
ISO/IEC 9126-4
ISO 20282-2
35
2. Design the user interface
ISO 9241: Ergonomic requirements for office work with visual display
terminals
Parts 10 to 17 give guidance on software
10 Dialogue principles
11 Guidance on usability
12 Presentation of information
13 User guidance
14 Menu dialogues
15 Command Language dialogues
16 Direct Manipulation dialogues
17 Form-filling dialogues
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36
Approaches to achieving usability
process quality
product quality
quality in use
life cycle
processes
development
process
product
effect of the
product
usability
capability
user centred
process
interface and
interaction
organisational
capability
ISOTR 18529
ISO 13407
ISO 9241 parts 10, 12-17
ISO/IEC 9126-2/3
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usability in
context
ISO 9241-11
ISO 14598-1
ISO/IEC 9126-1
ISO/IEC 9126-4
ISO 20282-2
37
3. ISO 13407: Human centred design process for
interactive systems
1. Plan the human
centred process
Meets requirements
2. Specify the
context of use
5. Evaluate
designs against
user requirements
3. Specify user
and organisational
requirements
4. Produce design
solutions
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38
ISO 13407 Scope
 Computer-based interactive systems

The detailed recommendations are applicable to computer
hardware and software
 Can apply the same principles to the design of any
system for use by humans




A pen
A chair
A meeting room
A conference
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TRUMP: Trial Usability Maturity Process
 EU-funded trial application of user-centred design
methods developed in previous research projects
(INUSE and RESPECT)
 Serco: apply the methods

Lloyds Register: Usability Maturity Assessment
 Inland Revenue/EDS - IT for 60,000 staff

RAD methodology
 Israel Aircraft Industries - aerospace systems

traditional methodology
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Typical approach to usability
feasibility
Usability group
requirements
user and task
analysis
design
implement
prototyping
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release
usability
test
41
TRUMP approach: “ubiquitous usability”
Plan
Process
Specify
Context of
Use
Specify
Requirements
Design
Solution
s
Evaluate against
Requirements
System lifecycle
feasibility
1.
Stakeholder
meeting
requirements
2. Context
of use
4. Usability
requirements
3.
Scenarios
5. Evaluate
existing
system
design
6. Prototyping
7. Style guide
implement
release
8.
Evaluation
10.
Collect
feedback
9. Usability
testing
www.usability.serco.com/trump/ucdmethods
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42
Conventional design process
How do we incorporate user centred design?
requirements
product
User
requirements
Deliver
Functional
requirements
Detailed
specification
Prototyp
e
evaluation
Function test
Code
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43
5. Evaluate
existing system
1. Plans
Context used for evaluation
2. Intended context of
use
3. Intended scenarios of
use
requirements
4. Quality in use
requirements
User
requirements
4. External
usability
requirements
4. Internal
usability
requirements
Scenarios used for evaluation
product
6.
Mock up
Use in
context
Functional
requirements
6. Paper
prototype
Prototyp
e
Detailed
specification
6. Paper
specificatio
n
7. Style
guide
Code
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evaluation
Function test
Inspection
7. Style guide
44
Methods: feasibility
1. Stakeholder meeting
A half-day meeting to identify and agree on the role of
usability, broadly identifying the intended context of use and
usability goals, and how these relate to the business
objectives and success criteria for the system.
2. Context of use
A half-day workshop to collect and agree detailed information
about the intended users, their tasks, and the technical and
environmental constraints.
3. Scenarios of use
A half day workshop to document examples of how users are
expected carry out key tasks in a specified contexts, to
provide an input to design and a basis for subsequent
usability testing.
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Methods: requirements
4. Evaluate an existing system
Evaluate an earlier version or competitor system to identify
usability problems and obtain measures of usability as an
input to usability requirements.
5. Usability requirements
A half-day workshop to establish requirements for
effectiveness, efficiency and satisfaction for the user groups
and tasks identified in the context of use analysis and in the
scenarios.
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46
Methods: design
6. Paper prototyping
Evaluation by users of quick low fidelity prototypes (using
paper or other materials) to clarify requirements and enable
draft interaction designs and screen designs to be rapidly
simulated and tested.
7. Style guide
Identify, document and adhere to industry, corporate or project
conventions for screen and page design.
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47
Methods: evaluation
8. Evaluation of machine prototypes
Informal usability testing with 3-5 representative users
carrying out key tasks to provide rapid feedback on the
usability of prototypes.
9. Usability testing
Formal usability testing with 8 representatives of a user group
carrying out key tasks to identify any remaining usability
problems and evaluate whether usability objectives have been
achieved.
10. Collect feedback from users
Collect information from sources such as usability surveys,
help lines and support services to identify any problems that
should be fixed in future versions.
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48
Cost benefits at IAI
 Development cost/benefits


A all the methods used (except Style Guide) resulted in savings in
development costs of between $5K and $70K for each method,
with a total saving of $330K.
The cost of using the methods was only $22K, giving a cost-benefit
ration of 1:15.
 Sales cost/benefits

Increased sales because customers would be more likely to buy
the product were estimated to be $400K
 Support cost/benefits

Reduced costs of training and support were estimated at £50K.
 Overall cost benefits

The overall costs of the maturity assessments and use of methods
was $27K. The total estimated savings and increased sales is
$780K, giving a cost-benefit ration of 1:29.
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Trial Application at IAI Bottom Line
 Positive Feedback from Participants
 A Definite Improvement in the Development Process
 Very Cost Effective and Low Cost
 Mostly Intuitive however tailoring sometimes required
 Expert Guidance needed in few techniques
 LAHAV decided to incorporate TRUMP techniques in it’s
standard development process
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50
IAI Conclusions
 Low cost simple methods for improving systems usability
are here
 The methods can be easily integrated into any software
development process
 The responsibility for quality in use should be transferred
to development organization
 The Methods and supporting means are available on the
Web
 No more Excuses
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51
Approaches to achieving usability
organisational
capability
process quality
product quality
quality in use
effect of the
product
life cycle
processes
development
process
product
usability
capability
user centred
process
interface and
interaction
ISOTR 18529
ISO 13407
ISO 9241 parts 10, 12-17
ISO/IEC 9126-2/3
©Serco Reproduction permitted provided the source is acknowledged
usability in
context
ISO 9241-11
ISO 14598-1
ISO/IEC 9126-1
ISO/IEC 9126-4
ISO 20282-2
52
4. Establish usability capability
ISO TR 18529: Human-centred lifecycle process descriptions
HCD.1 Ensure HCD content in system strategy
HCD.2 Plan and manage the HCD process
HCD.3 Specify the user and organisational requirements
HCD.4 Understand and specify the context of use
HCD.5 Produce design solutions
HCD.6 Evaluate designs against requirements
HCD.7 Introduce and operate the system
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53
Process improvement overview
1. Identify needs for usability process improvement
•
Use the usability maturity model in ISO TR 18529 to assess the
current capability of each organisation
2. Make the identified improvements to the software
development processes
•
Introduce simple user-based methods implementing ISO 13407
3. Reassess the usability capability the organisation
•
Assess the extent of the improvement
4. Identify the cost-benefits of the improvements
•
Integrate the methods into the documented processes
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54
Usability Maturity Model
HCD.2 Plan and manage the HCD process
 Consult stakeholders.
 Identify and plan user involvement.
 Select human-centred methods and techniques.
 Ensure a human-centred approach within the project
team.
 Plan human-centred design process.
 Manage human-centred process.
 Champion human-centred activities.
 Provide support for human-centred design
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Usability Maturity Model
HCD.3 Specify the user and organisational
requirements
 Clarify and document the system goals.
 Define stakeholders.
 Assess risk to stakeholders.
 Define the system.
 Generate the user and organisational requirements.
 Set usability objectives.
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56
Usability Maturity Model
HCD.4 Understand and specify the context of use
Identify and document
 user’s tasks.
 significant user attributes.
 organisational environment.
 technical environment.
 physical environment.
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57
Usability Maturity Model
HCD.5 Produce design solutions
 Allocate functions
 Produce composite task model
 Produce system design
 Use existing knowledge to develop design solutions
 Specify system
 Develop prototypes
 Provide user training
 Provide user support
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58
Usability Maturity Model
HCD.6 Evaluate designs against
requirements
 Specify and validate context of evaluation.
 Evaluate early prototypes in order to define the
requirements for the system.
 Evaluate prototypes in order to improve the design.
 Evaluate the system in order to check that the system
requirements have been met.
 Evaluate the system in order to check that the
required practice has been followed.
 Evaluate the system in use in order to ensure that it
continues to meet organisational and user needs.
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59

United Kingdom’s tax collection department

Employ over 60,000 staff in more than 600 local offices



Partnership with EDS for software development now
running for more than 5 years
JAD: Joint Application Development
RAD: Rapid Application Development
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60
Usability capability assessment
Formal CMM/SPICE style assessment by Lloyds Register
 Interviewed 13 stakeholders in twelve 3-hour sessions
over one week.

A conventional software process assessment procedure based
on SPICE (ISO 15504) was used.
 Produced a detailed profile and rich information about
where improvements would be beneficial.
 At a feedback meeting on the last day, it provided the
basis for an agreed set of improvement activities
 A second assessment a year later showed significant
improvements
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61
Inland Revenue/EDS Conclusions
 Significant improvement in all areas of usability maturity
 IR/EDS now strong in the “core” areas of context,
requirements, design and evaluation
 Evaluation activity rated as outstanding
 The methods are very cost effective and will be
incorporated into the documented development process
 “A step change in the awareness and practice of human
centred design within IR/EDS”.
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IAI LAHAV Background
 Expertise in Military Aircraft “Avionics Upgrade
Programs”
 Customers Worldwide
 User needs addressed by a group of Pilots
 Trial Application: PC-based Mission Planning system
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Usability capability assessment workshop
Process improvement workshop
 One-day workshop
 Review each process and activity in ISO TR 18529 in
detail
 Score each process as:

Not, Partly, Largely or Fully performed
 Note whether the process is managed

a documented part of normal procedures
 Establish a target level for each process on the same
scales
 A second assessment a year later showed significant
improvements
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Trial Application at IAI Bottom Line
 Positive Feedback from Participants
 A Definite Improvement in the Development Process
 Very Cost Effective and Low Cost methods
 LAHAV decided to incorporate TRUMP techniques in it’s
standard development process
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Process improvement conclusions
 The usability maturity model was a valuable tool for
identifying needs for process improvement


Inland Revenue:summative assessment requiring three person
weeks effort
IAI: a simpler formative one-day assessment
 A very promising way to make major process
improvements
www.usability.serco.com/trump
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ISO 13407 Conclusions
 ISO 13407 and ISO TR 18529 provide an internationally-agreed
description of good practice in user-centred design
 The content can be used to specify or evaluate:
 How usability should be incorporated into the development process
 Whether a project has applied user centred design
 Organisational capability in user-centred design
 Basis for process improvement
 Appropriate content for education and training courses in user centred
design
 Necessary areas of professional competence: professional accreditation
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www.usabilitynet.org
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