Interface Guidelines & Principles
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Transcript Interface Guidelines & Principles
Interface Guidelines & Principles
Focus on Users & Tasks
Not Technology
Interface Guidelines & Principles
7 principles for Interface Design
1. Focus on the users & tasks, not technology.
Easier said than done for programmers.
Interface Design vs. Development
Design
– Somewhat, creative human activity for interface.
– Specifies interface’s appearance & interactions.
– Here is where we do mock ups, specs, etc.
Development
– Interface production.
– Implementation of design.
– Here is where Java, C++, HTML, etc. come in
HCC does both
How to focus on users & tasks?
Must asks a few questions in the beginning.
Who
For whom is this product or service being
designed?
Who are the customers, users, experts, etc.
– Customers = Users = Experts ?
What is the background of the users?
– education, culture, ethics, age, sex, etc.
What
What is the product or service for?
– What problem does it solve?
– What value will it add?
What activity is it intended to support?
– What are the skills/knowledge of the users?
– What are the motivations for users?
How
How do the users work in the domain now?
– How will the product or service fit in or replace it?
How do users conceptualize the tasks now?
– How will they conceptualize the tasks later?
User Centered Design
User Centered Design
A way to force yourself to identify and
consider the relevant human factors in your
design
Helps reduce the number of decisions made
out of the blue, and helps focus design
activities
Helps document and defend decisions that
may be reviewed later
UCD - Know the Users
Ask the Who questions
– Skills, background, etc.
Know the user’s job
Possible exception
– World Wide Web, who are your users?
UCD – Participatory Design
Participatory Design
– The user takes a participatory role in the design
process.
Involve the users as much as possible, but
don’t over do it.
– How many people does it take to screw in a
light bulb?
UCD – Design to Prevent Errors
Common errors should be avoided.
– rm *.*, delete *.*
Through experience, you will learn how to
spot vulnerable areas that are error prone.
– Much easier said than done!
UCD – Optimize User Operations
Add shortcuts where necessary.
CAUTION!!!
– Shortcuts can be over rated in some systems.
– Know your users first and then decide on shortcuts.
UCD – Keep Control with User
The user should be in control or at least
think he/she is in control.
Manage user interaction and control point of
view.
UCD – Help the User
Provide assistance throughout your system.
The user should be able to get help any time
he/she wishes (control point of view).
Help is a difficult task because sometimes
users need help with the help.
User Centered Design
DESIGN
USE &
EVALUATE
IMPLEMENT
UCD: 9 Step Overview
1.
2.
3.
4.
5.
6.
7.
8.
9.
Define the Context
Describe the User
Task Analysis
Function Allocation
System Layout / Basic Design
Mockups & Prototypes
Pilot Test & Usability Testing
Iterative Test & Redesign
Updates & Maintenance
1. Define the Context
Context:
– Life critical systems, applications
– Industrial, commercial, military, scientific,
consumer
– Office, home, entertainment
– Exploratory, creative, cooperative
Market
Customer (not the same as the User)
…Design Impacts?…
2. Describe the User (!!)
Physical attributes
(age, gender, size, reach, visual angles, etc…)
Physical work places
(table height, sound levels, lighting, software version…)
Perceptual abilities
(hearing, vision, heat sensitivity…)
Cognitive abilities
(memory span, reading level, musical training, math…)
Personality and social traits
(likes, dislikes, preferences, patience…)
Cultural and international diversity
(languages, dialog box flow, symbols…)
Special populations, (dis)abilities
3. Task Analysis
Talk to and observe users (NOT customers)
doing what they do
List each and every TASK
Break tasks down into STEPS
ABSTRACT into standard tasks
(monitor, diagnose, predict, control, inspect, transmit,
receive, decide, calculate, store, choose, operate, etc.)
4. Function Allocation
Consider the whole system!
Decide who or what is best suited to perform
each task (or each step)
Base this on knowledge of system
hardware, software, human users,
communications protocols, etc.
Allocation constraints: Effectiveness;
Cognitive/affective; Cost; Mandatory
5. System Layout / Basic Design
Summary of the components and their
basic design
Cross-check with any Requirements
Documents; Human Factors refs; Hardware
specs; Budgets
Ensure that the system will support the
design and comply with constraints
6. Mockups & Prototypes
“Informed Brainstorming”
RAPIDLY mock up the user interfaces for
testing with real people
Pen and paper or whiteboard to start
Iterate, iterate, iterate!!
Increasingly functional & veridical
List audio & visual details at same levels of
detail in the prototypes
7. Pilot Test & Usability Testing
Pilot Test
– Small usability study before the real study.
– Pilot tests are conducted as a prelude to the real usability
test.
– Helps to refine the usability test process and procedures.
– Get preliminary results before the real test.
7. Pilot Test & Usability Testing
Get real (or representative) users to do what they do,
using the prototypes
Subjective and objective feedback. Sometimes users
“want” features that actually yield poor performance
Video tape, lots of notes
Feedback into the iterative evaluation & redesign of
the system
“Discount” usability testing can be very effective,
using fewer subjects, more rapid results
8. Iterative Test & Redesign
Repeat cycles of testing and reworking the
system, subject to cost/time constraints
Focus on Functionality First !
Plan for several versions during
development
9. Updates & Maintenance
In-the-field feedback, telemetry, user data,
logs, surveys, etc.
Analyze and make iterative redesign/test
recommendations
Updates and maintenance plan as part of
the design!
UCD: 9 Step Overview
1.
2.
3.
4.
5.
6.
7.
8.
9.
Define the Context
Describe the User
Task Analysis
Function Allocation
System Layout / Basic Design
Mockups & Prototypes
Pilot Tests & Usability Testing
Iterative Test & Redesign
Updates & Maintenance
UCD: Focusing Your Efforts
There are real-world constraints
Cutting out steps is not the way to
economize!
Optimize the efficiency of each step
Here: Focus on the context and the user, to
get the most value for the time spent
Concepts, Principles, Guidelines
No “cookbooks” (sorry!)
No simple, universal checklists
Think from perspective of user
There are many concepts, principles, and
guidelines to help you
Focus on higher level principles that apply
across situations, display types, etc.
Summary
Humans will use your system
Considering their many attributes, abilities, and
limitations will lead to a better design
It’s not just common sense!
Human Factors is the study of how our “human
factors” affect design
User Centered Design is a philosophy and a
process to help designers sort it all out
It matters! And it ain’t easy!
Practice makes better (never perfect!)