Transcript Document

SIMS 213:
User Interface Design & Development
Marti Hearst
Thurs, Jan 29, 2004
Discussion
Kent Sullivan, The Windows 95 User Interface: A
Case Study in Usability Engineering, CHI 1996.
A case study of the iterative design process.
Sullivan Case Study
– 12 people on the Windows 95 team!!
– Waterfall design method (compartmentalized; UI done at the
end during quality assurance stage) would produce an
unusable product.
– Method:
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Find most common tasks, and test on those
Compare to a baseline (Windows 3.1)
Rapid prototyping tools
Importance of usability testing!!
– Stepping back
• Found big problems
• Held a retreat to radically re-think things
Sullivan Case Study
– Decided to:
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Focus on scaffolding (beginner -> intermediate-expert)
Give up on too much backwards-compatibility with 3.1
Dump the huge design spec (!) Encouraged social interaction.
Continually informed outsiders as well as team members about the
design
– Fine tuning with usablity tests
• Holistic interface test in the lab
– Many participants!
• Longitudinal field study
– About Windows 3.1
• … a good demonstration of what happens when usability is not taken
into account
Readings for This and Next Lecture
Cooper (Inmates, Chs. 9-11)
Constantine & Lockwood Ch. 5
Newman & Landay article
Why User-Centered Design?
System will fail if it:
– does not do what the user needs
– is inappropriate for the user
Why don’t we just define what a “good interface”
is?
– There is a huge variety of users and tasks
– Guidelines are usually too vague
e.g. “Provide feedback”, “Be intuitive”
Slide by James Landay
Participatory Design
A subset of user-centered design
User actively participates in design of the system
Pros:
– potentially more accurate information about the tasks
– more opportunity for users to influence the design
decisions
– buy-in from sense of participation
– potential greater acceptance of final system
Slide adapted from Ben Shneiderman
Participatory Design
Cons (potential):
– more costly
– lengthier implementation period
– antagonism from those whose suggestion are not
incorporated
– force designers to compromise design
– exacerbate personality conflicts between designers and
users
– highlight organizational politics
Slide adapted from Ben Shneiderman
User-Centered Design Overview
Needs assessment
– Find out
• who users are
• what their goals are
• what tasks they need to perform
– Task Analysis
• Characterize what steps users need to take
• Create scenarios of actual use
• Decide which users and tasks to support
Design based on this
Evaluation
– Test interface by “walking through” tasks
– Do this before implementation
Caveats
Politics
– advocating change can cause controversy
– get a sense of the organization
– important to get buy-in from all those involved
Don’t design forever without prototyping
– rapid prototyping, evaluation, & iteration is key to
technique
Systems level apps are poor candidates
– networking, etc.
Slide by James Landay
Example: Student Course Enrollment:
How to Help Students Achieve their Goals?
achieve lifetime of success
become successful IT manager
learn to build useful systems
enroll in sims 213
Help Users Achieve Goals
Example: Course Enrollment Software
– What matters from the programmers’ point of view?
– What matters from users’ point of view?
– What about the course administrators?
User-Centered Design Example
You have been hired by Pizzas R Us (PRU)
Design a system to
– make online orders from the web
Also considering special features
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online discount coupons
allowing party orders in advance
customer recommendations, linking to reviews
comparing local pizza parlors
User-centered Design Example
Your job: figure out
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how people do their pizza ordering now
how they would like to do it online
what features would make sense when
must also take into account the needs of the pizza parlor
owners and workers.
This is the needs assessment.
Techniques:
– Observation
– Interview
– Study existing successful designs
User-Centered Design Example
Observation
– Visit one or more pizza parlors. Observe how people
achieve their pizza ordering goals.
– Observe what the counter people need to do.
Optionally: interview these people
User-Centered Design Example
Interview
– Prepare a list of questions about how people do their pizza
ordering and what they would like in an automated ordering
system.
– Interview at least three people about what they would like in
an automated ordering system and how they would like it to
work.
• Try to identify people with different needs and preferences, with
respect to their attitudes about using online ordering systems.
– Ask them what, if anything, must be in the system in order
for them to prefer it over a phone ordering system or an inperson ordering system.
(E.g., no busy signals, cheaper prices, comparison shopping, faster
service, or would they prefer anything over current methods.)
User-Centered Design Example
Consider existing designs
– Look at least one existing on-line food ordering web
site and see how they handle these tasks.
User-Centered Design Example
Procedure
– Answer the needs assessment questions
– Try to understand the basic tasks that are currently supported
within pizza parlors and via phone orders
– Make a table showing
• user types
• tasks
• (guesses about) relative frequencies of tasks
– Decide which of the new tasks customers may perform using
the new interface.
• Make note of which ideas you decided to drop based on your
interviews.
Needs Assessment Questions
Who is going to use the system?
What tasks do they now perform?
What tasks are desired?
How are the tasks learned?
Where are the tasks performed?
What is the relationship between the user and
the data?
Slide adapted from James Landay
Needs assessment Questions
What other tools does the user have?
How do users communicate with each other?
How often are the tasks performed?
What are the (time) constraints on the task?
What happens when things go wrong?
Slide adapted from James Landay
Task Analysis
Characterize what happens when users perform
typical tasks
Tools:
– table of user communities vs. tasks
• Who x What
– table of task sequences
– flowchart or transition diagram
– videotape depicting scenario
Slide adapted from Ben Shneiderman
How Often Do Users Perform the Tasks?
Frequent users remember more details
Infrequent users may need more prompting
Which function is performed
– most frequently?
– by which users?
– optimize system for tasks that will improve
perception of its performance
Slide adapted from James Landay's
Augment Table with Percentages
(What percentage of the is this task done by this person)
(Numbers are only suggestive, adapted from Shneiderman 98)
Job Title
Query by Patient
Update Data
14%
11%
Physician
6%
4%
Supervisor
1%
1%
Nurse
Appointment
administrator
Query across
Patients
Add Attributes
4%
26%
Clinical researcher
8%
Database
programmer
2%
2%
User-Centered Design Example
Scenarios
– Create three scenarios that will exercise these tasks
in the proposed interface
– Create a description in which you outline
• A person’s background
• Their goal(s)
• How they achieve these goals using the steps in the
system
– Note: this will change a bit when we use personas
User-Centered Design Example
Sketch an initial design
– Explain how the pizza ordering system will work.
• Either a textual description or a flow chart (or both)
showing the sequences of steps that will be allowed in the
system.
• Provide rough sketches showing at least three of the
important screens.
– Walk through at least one of the scenarios you
developed and show how it can be handled by the
interface.