Transcript Chapter 6

Chapter 6
Design Thinking
Chapter 6
• Design processes
– Double diamond
– Human-centered design
• Activity-centered vs. human centered design
• The industrial design context
– Budget
– Time
– Variety of participants
• Conflicting requirements
• Accessibility, universal/inclusive design
– Avoiding stigma
• Complexity vs. confusion
– Standards
• Deliberately making things difficult
Incremental Problem Specification
• “you cannot understand the problem without
having a concept of the solution in mind”
Horst Rittel
• Asymmetry of knowledge
Description of Problem
Space (customer)
Description of Solution
Space (sales rep)
solution
What is involved in the
process of design
• Observation
– Identifying needs and establishing requirements for the user
experience
• Idea Generation
– Developing alternative designs to meet these
• Prototyping
– Building interactive prototypes that can be communicated and
assessed
• Testing
– Evaluating what is being built throughout the process and the user
experience it offers
Core characteristics of
human-centered design
• Ideally
– Stakeholders, including users, should be involved
through the development of the project
– Iteration is needed through the core activities
– Each iteration gets design closer to final design
Why go to this length?
• Help designers:
– understand how to design interactive products
that fit with what people want, need and may
desire
– appreciate that one size does not fit all
e.g., teenagers are very different to grown-ups
– identify any incorrect assumptions they may have
about particular user groups
e.g., not all old people want or need big fonts
– be aware of both people’s sensitivities and their
capabilities
Usability goals
•
•
•
•
•
•
Effective to use
Efficient to use
Safe to use
Have good utility
Easy to learn
Easy to remember how to use
User experience goals
•
•
•
•
•
•
•
•
•
satisfying
enjoyable
engaging
pleasurable
exciting
entertaining
helpful
motivating
emotionally fulfilling
• boring
• frustrating
• aesthetically pleasing
• supportive of creativity
• supportive of creativity
• rewarding
• fun
• provocative
• surprising
• enhancing sociability
• challenging
• annoying
• cutesey
Design principles
• Generalizable abstractions for thinking about
different aspects of design
• The do’s and don’ts of interaction design
• What to provide and what not to provide at the
interface
• Derived from a mix of theory-based knowledge,
experience and common-sense
Usability principles
• Similar to design principles, except more
prescriptive
• Used mainly as the basis for evaluating
systems
• Provide a framework for heuristic evaluation
Usability principles (Nielsen 2001)
•
•
•
•
•
•
•
•
•
•
Visibility of system status
Match between system and the real world
User control and freedom
Consistency and standards
Help users recognize, diagnose and recover from errors
Error prevention
Recognition rather than recall
Flexibility and efficiency of use
Aesthetic and minimalist design
Help and documentation
What is involved in design?
• It is a process:
– a goal-directed problem solving activity informed by
intended use, target domain, materials, cost, and
feasibility
– a creative activity
– a decision-making activity to balance trade-offs
• It is a representation:
– a plan for development
– a set of alternatives and successive elaborations
Importance of involving users
• Expectation management
–
–
–
–
Realistic expectations
No surprises, no disappointments
Timely training
Communication, but no hype
• Ownership
– Make the users active stakeholders
– More likely to forgive or accept problems
– Can make a big difference to acceptance and success of
product
Degrees of user involvement
• Member of the design team
–
–
–
–
Full time: constant input, but lose touch with users
Part time: patchy input, and very stressful
Short term: inconsistent across project life
Long term: consistent, but lose touch with users
• Newsletters and other dissemination devices
– Reach wider selection of users
– Need communication both ways
• Combination of these approaches
What is a user-centered approach?
User-centered approach is based on:
– Early focus on users and tasks: directly studying cognitive,
behavioral, anthropomorphic & attitudinal characteristics
– Empirical measurement: users’ reactions and performance
to scenarios, manuals, simulations & prototypes are
observed, recorded and analysed
– Iterative design: when problems are found in user testing,
fix them and carry out more tests
Some practical issues
• Who are the users?
• What are ‘needs’?
• Where do alternatives come from?
• How do you choose among alternatives?
Who are the users/stakeholders?
• Not as obvious as you think:
–
–
–
–
–
those who interact directly with the product
those who manage direct users
those who receive output from the product
those who make the purchasing decision
those who use competitor’s products
• Three categories of user (Eason, 1987):
– primary: frequent hands-on
– secondary: occasional or via someone else
– tertiary: affected by its introduction, or will influence its purchase
Who are the stakeholders?
Check-out operators
• Suppliers
• Local shop
owners
Managers and owners
Customers
What are the users’ capabilities?
Humans vary in many dimensions:
— size of hands may affect the size and positioning of input
buttons
— motor abilities may affect the suitability of certain input
and output devices
— height if designing a physical kiosk
— strength - a child’s toy requires little strength to operate,
but greater strength to change batteries
— disabilities (e.g. sight, hearing, dexterity)
What are ‘needs’?
• Users rarely know what is possible
• Users can’t tell you what they ‘need’ to help them achieve
their goals
• Instead, look at existing tasks:
– their context
– what information do they require?
– who collaborates to achieve the task?
– why is the task achieved the way it is?
• Envisioned tasks:
– can be rooted in existing behaviour
– can be described as future scenarios
Where do alternatives
come from?
• Humans stick to what they know works
• But considering alternatives is important to ‘break
out of the box’
• Designers are trained to consider alternatives,
engineers often are not (focus on problem solving)
• How do you generate alternatives?
—‘Flair and creativity’: research and synthesis
—Seek inspiration: look at similar products or look
at very different products
IDEO TechBox
• Library, database, website - all-in-one
• Contains physical gizmos for inspiration
From: www.ideo.com/
The TechBox
Working in multidisciplinary teams
• Many people from different
backgrounds involved
• Different perspectives
and ways of seeing
and talking about things
• Benefits
– more ideas and designs
generated
• Disadvantages
– difficult to communicate and
progress forward the designs being create
How do you choose among
alternatives?
• Evaluation with users or with peers, e.g. prototypes
• Technical feasibility: some not possible
• Quality thresholds: Usability goals lead to usability
criteria set early on and check regularly
—safety: how safe?
—utility: which functions are superfluous?
—effectiveness: appropriate support? task coverage,
information available
—efficiency: performance measurements
Testing prototypes to choose among
alternatives
Design Processes: Lifecycle models
• Show how activities are related to each other
• Lifecycle models are:
—management tools
—simplified versions of reality
• Many lifecycle models exist, for example:
—from software engineering: waterfall, spiral, JAD/RAD,
Microsoft, agile
—from HCI: Star, usability engineering
A simple interaction design model
Exemplifies a user-centered design approach
Traditional ‘waterfall’ lifecycle
Spiral model (Barry Boehm)
Important features:
— Risk analysis
— Prototyping
— Iterative framework so ideas can be checked and
evaluated
— Explicitly encourages considering alternatives
Good for large and complex projects but not
simple ones
Spiral Lifecycle model
The Star lifecycle model
• Suggested by Hartson and Hix (1989)
• Important features:
—Evaluation at the center of activities
—No particular ordering of activities;
development may start in any one
—Derived from empirical studies of interface
designers
The Star Model (Hartson and Hix, 1989)
Usability engineering lifecycle model
• Reported by Deborah Mayhew
• Important features:
– Holistic view of usability engineering
– Provides links to software engineering approaches, e.g. OOSE
– Stages of identifying requirements, designing, evaluating,
prototyping
– Can be scaled down for small projects
– Uses a style guide to capture a set of usability goals
ISO 13407
Design Process Summary
Four basic activities in the design process
1.
2.
3.
4.
Identify needs and establish requirements
Design potential solutions ((re)-design)
Choose between alternatives (evaluate)
Build the artefact
User-centered design rests on three principles
1.
2.
3.
Early focus on users and tasks
Empirical measurement using quantifiable & measurable
usability criteria
Iterative design
Lifecycle models show how these are related
Prototyping and construction
• What is a prototype?
• Why prototype?
• Different kinds of prototyping
low fidelity
high fidelity
• Compromises in prototyping
vertical
horizontal
• Construction
What is a prototype?
In other design fields a prototype is a small-scale
model:
• a miniature car
• a miniature building or town
What is a prototype?
In interface design it can be (among other things):
•
•
•
•
•
•
•
a series of screen sketches
a storyboard, i.e. a cartoon-like series of scenes
a Powerpoint slide show
a video simulating the use of a system
a lump of wood (e.g. PalmPilot)
a cardboard mock-up
a piece of software with limited functionality written in the target language
or in another language
Why prototype?
• Evaluation and feedback are central to interaction design
• Stakeholders can see, hold, interact with a prototype more
easily than a document or a drawing
• Team members can communicate effectively
• You can test out ideas for yourself
• It encourages reflection: very important aspect of design
• Prototypes answer questions, and support designers in
choosing between alternatives
What to prototype?
• Technical issues
• Work flow, task design
• Screen layouts and information display
• Difficult, controversial, critical areas
Low-fidelity Prototyping
• Uses a medium which is unlike the final medium,
e.g. paper, cardboard
• Is quick, cheap and easily changed
• Examples:
sketches of screens, task sequences, etc
‘Post-it’ notes
storyboards
‘Wizard-of-Oz’
Storyboards
• Often used with scenarios, bringing more detail,
and a chance to role play
• It is a series of sketches showing how a user
might progress through a task using the device
• Used early in design
Sketching
• Sketching is important to low-fidelity prototyping
• Don’t be inhibited about drawing ability. Practice
simple symbols
Card-based prototypes
• Index cards (3 X 5 inches)
• Each card represents one screen or part of
screen
• Often used in website development
‘Wizard-of-Oz’ prototyping
• The user thinks they are interacting with a computer, but a
developer is responding to output rather than the system.
• Usually done early in design to understand users’
expectations
User
>Blurb blurb
>Do this
>Why?
High-fidelity prototyping
• Uses materials that you would expect to be in the final
product.
• Prototype looks more like the final system than a low-fidelity
version.
• For a high-fidelity software prototype common environments
include common interface scripting languages.
• Danger that users think they have a full system…….see
compromises
Compromises in prototyping
• All prototypes involve compromises
• For software-based prototyping maybe there is a slow
response? sketchy icons? limited functionality?
• Two common types of compromise
• ‘horizontal’: provide a wide range of functions, but
with little detail
• ‘vertical’: provide a lot of detail for only a few
functions
• Compromises in prototypes mustn’t be ignored. Product
needs engineering
Construction
• Taking the prototypes (or learning from them) and
creating a whole
• Quality must be attended to: usability (of course),
reliability, robustness, maintainability, integrity,
portability, efficiency, etc
• Product must be engineered
Evolutionary prototyping
‘Throw-away’ prototyping
Conceptual design: from
requirements to design
• Transform user requirements/needs into a conceptual
model
• “a description of the proposed system in terms of a set of
integrated ideas and concepts about what it should do,
behave and look like, that will be understandable by the
users in the manner intended”
• Don’t move to a solution too quickly. Iterate, iterate, iterate
• Consider alternatives: prototyping helps
Is there a suitable metaphor?
• Interface metaphors combine familiar knowledge with new
knowledge in a way that will help the user understand the
product.
• Three steps: understand functionality, identify potential
problem areas, generate metaphors
• Evaluate metaphors:
How much structure does it provide?
How much is relevant to the problem?
Is it easy to represent?
Will the audience understand it?
How extensible is it?
Considering interaction types
• Which interaction type?
How the user invokes actions
Instructing, conversing, manipulating or
exploring
• Do different interface types provide insight?
WIMP, shareable, augmented reality, etc
Expanding the conceptual model
• What functions will the product perform?
What will the product do and what will the human do
(task allocation)?
• How are the functions related to each other?
Sequential or parallel?
Categorisations, e.g. all actions related to telephone
memory storage
• What information needs to be available?
What data is required to perform the task?
How is this data to be transformed by the system?
Using scenarios in conceptual design
• Express proposed or imagined situations
• Used throughout design in various ways
scripts for user evaluation of prototypes
concrete examples of tasks
as a means of co-operation across professional
boundaries
• Plus and minus scenarios to explore extreme cases
Generate storyboard from scenario
Generate card-based prototype
from use case
Tool support - DENIM
Prototyping Summary
• Different kinds of prototyping are used for different
purposes and at different stages
• Prototypes answer questions, so prototype appropriately
• Construction: the final product must be engineered
appropriately
• Conceptual design (the first step of design)
• Consider interaction types and interface types to prompt
creativity
• Storyboards can be generated from scenarios
• Card-based prototypes can be generated from use cases
Design Rationale
• Used to support the design process by
– Encouraging exploration of different potential designs
– Motivating the conceptual evaluation of potential
design features
– Recording this activity as partial documentation of
design
• Horst Rittel meant IBIS (issue-based information
system) approach to slow down designers to
make them more reflective on their design
IBIS
• Issue – a design question
– Position – a potential answer to the question
• Argument – reasons for/against the potential answer
• Issues are not independent
– Can create a graph of relationships among issues
• Part/whole relations among issues
• Prerequisite/informing relations among issues
Chapter 6
• Design processes
– Double diamond
– Human-centered design
• Activity-centered vs. human centered design
• The industrial design context
– Budget
– Time
– Variety of participants
• Conflicting requirements
• Accessibility, universal/inclusive design
– Avoiding stigma
• Complexity vs. confusion
– Standards
• Deliberately making things difficult