User centered design
What is User-Centered Design?
• An approach to UI development and system
• Focuses on understanding:
–Users, and –Users, and
–Their goals and tasks, and
–The environment (physical, organizational, social)
• Pay attention to these throughout
ISO on User-centered Design
• ISO 13407 describes human-centered design
processes for interactive systems
• Principles of human-centered design:
–Active involvement of users –Active involvement of users
–Appropriate allocation of function between user
–Iteration of design solutions
–Multidisciplinary design teams
ISO on User-centered Design (2)
• Essential activities in human-centered design:
–Understand and specify the context of use
–Specify the user and organizational requirements
–Produce design solutions (prototypes) –Produce design solutions (prototypes)
–Evaluate designs with users against requirements
What is a user-centeredapproach?
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
– Iterative design: when problems are found in user testing, fix them
and carry out more tests
Four basic activities
There are four basic activities in Interaction Design:
– 1. Identifying needs and establishing requirements
– 2. Developing alternative designs
– 3. Building interactive versions of the designs
– 4. Evaluating designs
A simple interaction design model
Exemplifies a user-centered design approach
Some practical issues
• Who are the users?
• What are ‘needs’?
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 – 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
What are the users’ capabilities?
—size of hands may affect the size and positioning of input
—motor abilities may affect the suitability of certain input
and output devices
—height if designing a physical kiosk —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)
—abilities also vary according to context
What are ‘needs’?
• Users rarely know what is possible
• Users can’t tell you what they ‘need’ to help them achieve their
• Instead, look at existing tasks:
–what information do they require? –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
Brief overview of common methods
to gather user data
Choosing and combining techniques
• Unstructured -are not directed by a script. Rich but not
• Structured -are tightly scripted, a questionnaire delivered
verbally. Replicable but may lack richness.
• Semi-structured -guided by a script but interesting issues can • Semi-structured -guided by a script but interesting issues can
be explored in more depth. Can provide a good balance
between richness and replicability.
• Two types:
−‘closed questions’have a predetermined answer
format, e.g., ‘yes’or ‘no’
−‘open questions’do not have a predetermined format
• Closed questions are easier to analyze
−Long questions −Long questions
−Compound sentences -split them into two
−Jargon and language that the interviewee may not
−Leading questions that make assumptions e.g., why do
you like …?
−Unconscious biases e.g., gender stereotypes
Enriching the interview process
• Props -devices for prompting interviewee, e.g., a prototype,
• An approach to ethnographic study. Often conducted as an
apprenticeship where user is expert, designer is apprentice
• A form of interview, but
—at users’workplace (workstation)
—2 to 3 hours long
• Four main principles: • Four main principles:
—Context: see workplace & what happens
—Partnership: user and developer collaborate
—Interpretation: observations interpreted by user and developer
—Focus: project focus to understand what to look for
• Questions can be closed or open
• Closed questions are easier to analyze, and may be done by
• Can be administered to large populations
• Paper, email and the web used for dissemination
• Sampling can be a problem when the size of a population is
unknown as is common online
• The impact of a question can be influenced by question order.
• Do you need different versions of the questionnaire for different
• Provide clear instructions on how to complete the questionnaire.
• Strike a balance between using white space and keeping the
• Decide on whether phrases will all be positive, all negative or • Decide on whether phrases will all be positive, all negative or
Advantages of online questionnaires
Responses are usually received quickly
No copying and postage costs
Data can be collected in database for analysis
Time required for data analysis is reduced Time required for data analysis is reduced
Errors can be corrected easily
Problems with online questionnaires
Sampling is problematic if population size is unknown
Preventing individuals from responding more than once
Individuals have also been known to change questions in
• Direct observation in the field
– Structuring frameworks
– Degree of participation (insider or outsider)
• Direct observation in controlled environments • Direct observation in controlled environments
• Indirect observation: tracking users’activities
– Interaction logging
Structuring frameworks to guide
• -The person. Who?
• The Goetz and LeCompte (1984) framework: • The Goetz and LeCompte (1984) framework:
-What is their role?
-Whendoes the activity occur?
-Whereis it happening?
-Whyis it happening?
-Howis the activity organized?
Ethnography is a philosophy with a set of techniques that
include participant observation and interviews
Debate about differences between participant observation
Ethnographers immerse themselves in the culture that they
A researchers degree of participation can vary along a scale A researcher’s degree of participation can vary along a scale
from ‘outside’to ‘inside’
Analyzing video and data logs can be time-consuming
Collections of comments, incidents, and artifacts are made
• Co-operation of people being observed is required
• Informants are useful
• Data analysis is continuous
• Interpretivist technique
• Questions get refined as understanding grows
• Reports usually contain examples
Direct observation in a controlled setting
• Think-aloud technique
Choosing and combining techniques
• Depends on
–The focus of the study
–The participants involved
–The nature of the technique
–The resources available