Routine performnce Reduces or prevents humn error Prevents or recovers from system error Plesnt to use usble useful We wnt to improve usbility If you cnnot mesu
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Agenda
- Evaluation overview
- Usability evaluation methods
- Heuristic evaluation
Online lecture from Stanford HCI Group.
Scott Klemmer in Section with discussion.
In coming episodes
- Web analytics
- Think aloud protocol
- Clients: Reports
p.s. any questions on affinity diagramming or competitive analysis ?
What is usability?
A usable product:
• Supports routine performance
• Supports non-routine performance
• Reduces or prevents human error
• Prevents or recovers from system error
• Pleasant to use
usable ≠ useful
We want to improve usability!
If you cannot measure it,
you cannot improve it.
Usability Evaluation Methods
Empirical methods $ $ $
– Observation
– Experimentation
Analytical methods $
– Derived from physical, psychological, sociological, or design theories
– Heuristics derived from experience
Empirical (testing) methods
• Contextual inquiry > done
• Web analytics > coming
• Think aloud > coming
• Remote testing
• Log analysis
• Eye tracking
• “Wizard of Oz” studies
• Surveys and questionnaires
• Diary studies
Analytical (inspection) methods
• Heuristic evaluation (UIM1 Ch2)
• The GOMS (Goals, Operators, Methods, and Selection rules) family
– Keystroke-Level Model (KLM)
• Cognitive walkthrough (UIM1 Ch5)
• Pluralistic walkthrough (UIM1 Ch3)
1UIM = Usability Inspection Methods, Nielsen &
Mack
Analytical (inspection) methods
“Discount usability engineering methods” –Jakob Nielsen (not so much of $$)
Usually a small team of evaluators using analytical methods to review an interface based on recognized usability principles
Heuristic evaluation
Brief the group
Evaluate individually
Aggregate issues
Apply severity ratings
Summarize findings
Step 0: Brief the group
Heuristic evaluation methodology (this)
Domain briefing
– Important if evaluators are unfamiliar with the product’s domain
Scenario briefing
– Can optionally include specific tasks or scenarios or allow evaluators to explore on their own
Step 1: Evaluate individually
Two passes
1. Inspect flow (and optional tasks/scenarios)
2. Inspect each element against heuristics
Recognized usability principles
– 10 Nielsen heuristics (UIM Ch2, p.30)
Nielsen’s Heuristics
H1: Visibility of system status
H2: Match between system and real world
H3: User control and freedom
H4: Consistency and standards
H5: Error prevention
H6: Recognition rather than recall
H7: Flexibility and efficiency of use
H8: Aesthetic and minimalist design
H9: Error recovery
H10: Help and documentation
Step 3: Apply severity ratings
4 Catastrophic
– Product cannot be released
3 Major
– High-priority issue
2 Minor
– Good to fix when there’s a lull
1 Cosmetic
– Icing on the cake (these rarely get done)
0 Not a problem
– I don’t agree that this is a problem at all
Justification:
– Frequency: Common or rare occurrence?
– Impact: How bad is it? How hard to recover?
– Persistence: One-time problem users can work around or unavoidable problem?
For each issue, average the rating from each evaluator
Step 4: Summarize findings:
Executive summary
What are the important take-aways for people who do not read the individual Usability Aspect Reports?
Look for the forest in the trees
– Consider affinity diagramming
Audience: Project managers, team leads
Heuristic evaluation advantages
“Discount usability engineering”
Low intimidation
Don’t need to identify tasks, activities
Can identify obvious fixes
Can expose problems user testing doesn’t
Provides a shared language for talking
about usability recommendations
Heuristic evaluation disadvantages
Un-validated
Inconsistent
False alarms -- problems unconnected with tasks
May be hard to apply to new technology
What is a competitive analysis?
A comparison between
two or more products
that meet similar user
needs.
Why perform a competitive analysis?
Understand the marketplace
– Products become successful for a reason
– Provide direction to management
– Exploit strengths and weaknesses
Build domain knowledge
– Learn best practices
– Identify common patterns, language
When should you perform a competitive analysis?
Research phase
– Study existing products to get the lay of the land
Evaluation phase
– See how your product/prototype compares to existing products
Who is your audience?
– Design team
– Management
– External stakeholders
What is your deliverable?
– Presentation
– Walkthroughs
– Executive summary
What if you don’t find competitors?
A: others tried and failed
B: you didn’t look hard enough
C: it’s a blue ocean
Metrics
– Feature checklist
– Walkthrough
– Expert review
– User testing
Dependent on time, budget, access to competing products, and goals
Feature checklist
A high-level inventory of the features, content, and other attributes provided by each product
The point is not an exhaustive list but to highlight meaningful differences
Don’t forget about attributes like
– Price, license, availability
– OS, hardware requirements
– Popularity
– Navigation tools, search
As you evaluate you may uncover new attributes you wish to evaluate
Walkthrough
Define tasks
For each product, perform tasks while taking screenshots (requires access!)
Assemble screenshots into a slideshow and provide captions describing user actions and system animations, feedback, and delays
Expert review
Heuristic evaluation (Nielson) – holistic
Cognitive walkthrough – task specific
User testing
Time on task
Think aloud protocol
Surveys, questionnaires
Step 3: Summarize products
Brief summary highlighting strengths, weaknesses, and unique features of each product
Include illuminating quotes, screenshots, and/or videos
Step 4: Recommend courses of action
Executive summary
If your product was analyzed, how did it compare?
Your audience will recall only a couple of recommendations and takeaways; make sure they’re the right ones
Executive summary
- Lead with something interesting
- Provide recommendations or conclusions and justify them
- Use proper grammar (see Strunk & White)
- If you can remove a word, do it
- <10% overall length of the report
Executive summary
First we looked at twelve different chat clients and discovered that they basically do the same things but some of them have a lot of more customization options than our chat client does. Also, audio and video are popular.
Executive summary
While all chat clients offer similar core functionality, most offer more customization
options than ours. We recommend working
with users to determine whether additional
customization options would be useful. In
addition, several of the most popular chat
clients now offer audio and video
communication. We recommend considering
these features for future releases.
How might we improve the
measuring cup?
- It sometimes slippery
- Handles get hot
- Nobody complained about measuring part
- But how do you measure the liquid level?
How might we improve the
measuring cup? (solution)
- Numbers are visible from above
- Elegant solution by OXO’s Alex Lee.
- Still improvements: looks like medical device.
HCD Lessons:
- I he asked people what they wanted, they would have said faster horses. Remember?
- FOR User Interfaces:
- Observing actions
- Evaluating outcomes
Two Gulfs
- First step to cross: The Gulf of Execution
- How the user know what to do?
- Second step to cross: The Gulf of Evaluation
- How the user know what happened?
The making of gulfs. How easily can someone:
- Determine the function of the device?
- Tell what actions are possible?
- Determine mapping from intention to physical movement?
- Perform the action?
- Tell what state the system is in? / if its in desired state?
- Determine mapping from state to interpretation
To reduce gulfs, provide …
- Visibility (perceived affordances or signifiers)
- Feedback
- Consistency (also known as standards)
- Non-destructive operations (hence the importance of undo)
- Discoverability: All operations can be discovered by systematic exploration of menus
- Reliability. Operations should work. Period. And events should not happen suddenly.
Bu using you know look at this:
- video
Direct manipulation
- Immediate feedback on actions
- Continuous representation of objects
- Leverage metaphor
Eye to the Future: Gestures
- The solution to menu creep?
- Even more direct?
To learn more …
- Don Norman, The Design of Everyday Things
- Hutchins, Hollan, Norman, Direct manipulation interfaces, 1985
Mental Models
- Key to good design:
- What makes an interface learnable?
- What leads to errors?
The goal: design beacons the right model
- User’s model develops through interaction with the system
- Designers often expects user’s model to be the same as theirs
- But often it isn’t!
Conceptual model mismatch
- Mismatch between designer’s & user’s conceptual models leads to …
- Slow performance
- Errors
- Frustration
- …
- Mental models arise from experience, metaphor; and analogical reasoning
- “A text processor is a typewriter”
- We have models (beliefs) about our own behavior, of others, of objects, software …
- Our models are incomplete, inconsistent, unstable in time, and often rife with superstition
Direct manipulation provides
- Leverages real-world metaphors
- Good idea of how each object works and how to control it.
- Interface discloses how to use it.
“If technology is to provide an advantage, the correspondence to the real world must break down at some point.”
- Jonathan Grudin
To learn more …
- JM Carroll, JR Olson, Mental models in human-computer interaction: Research issues, 1987
- Don Norman, Design of Everyday Things
- James Reason, Human Error
H <-> H. How to interview people?
Possibly your most important skill
• hear about people’s experiences
• learn their meaning & feelings
• discover design opportunities
Interviewing skills a basis for more advanced methods--survey design, contextual inquiry, think-aloud, task analysis, and so forth
What and why?
An interview is a method of asking questions and listening
– Uses a planned interview protocol – a set of questions
– Ask what you can’t observe
I know you are a nursing supervisor. If I followed you through a typical day, what would I see you doing?
Types of questions
Close-ended (“forced choice”)
- In what year were you born?
- Are you satisfied with your hospital?
- On a scale from 1 to 10, how much do you like your job?
Open-ended
- What is the most enjoyable part of your job?
- If I were in the emergency room of your hospital, what would I notice first?
Question options
Behavioral questions
“Can you describe a recent occasion when
a patient alert was sounded, and tell me
what you did?”
Feeling questions
Knowledge questions
“If a patient says she is in pain, what do
you look for?”
Background; ratings (leave for last, or even better, a private questionnaire)
Planning
Decide whom you will interview
Plan your interview protocol
Ethical checklist:
- How will you explain your purpose?
- What promises will you make?
- Any risks, psychological or otherwise?
- How will you achieve confidentiality and data security?
- How will you get informed consent?
- How will you record and take notes?
Test your protocol and revise
Starting the interview
Everything depends on trust and rapport. So what do you do first?
[Rapport occurs when two or more people feel that they are in sync or on the same wavelength because they feel similar or relate well to each other.] by Wikipedia
Good and poor follow ups
Interview with John, a student in a drug treatment program.
I. Does anything in the program stand out for you?
J. Yeah, the hot seat
I. The hot seat is where someone is the focus of attention?
J. Right
I. So what was it like? Is it different with different people?
J. Yeah, it depends
Clear language
Interview with low-income mother who has been given an iPad for a research project on energy-saving practices
I. So, how do you like your iPad?
M. My son is using it.
I. What apps is he running?
M. I’m not sure.
I. What about your Internet connectivity; is your wireless working ok?
Other good question types
Illustrative questions
Some nurses hate working at night, but others like the flexibility. What’s your experience?
Role-playing questions
Suppose I were a new nurse just coming to this hospital, and I asked you what I should do to succeed. What would you tell me?
Preparatory questions
We’ve been talking about your job. Now I want to ask you about how you got to be where you are today.
Encourage your interviewee
That was really helpful.
We are about halfway through the interview. It’s going really well. How’s it going for you?
I realize this is a sensitive issue for you. You should decide how comfortable you are talking about it.
Embodied cognition
• The idea is that we don't just think with our minds, we also think with our bodies
• A good posture to empathize with your interviewee is. . . their posture
• Best posture to understand your interviewee is. . their posture
• Mimicry works but NOT if the other is socially incompetent or resistant
The final interview question
What should I have asked you that I didn’t think to ask?
That’s all I wanted to ask you. Anything you want to add?
(or)
How did the interview go for you? Keep the recorder on!
Lessons: Strategic interviewing
Information gathering not accusatory or blame-finding
– I asked Scott, oh, where did everyone live?
– “How did you get into the city when they blocked it off? “Who else was with you?”
Ask some unanticipated questions (less boring & less likely to be rehearsed) and don’t be afraid to probe for examples or “tell me more”
– Can you show me your wines?
– Would you introduce me to your manager?
Lessons: Coding
• Trick is to get the right level, not replicate what the interviewee says but not so abstract as to be useless
• Think about themes that are actionable—something you could improve through design
• Be sure to hit feelings, goals and subgoals, interactions with others, context
Design for people
- People’s tasks, goals and values drive development
- Work processes of the users within the work
- Access decisions from the user’s point of view
- Context awareness.
- Talk to the actual experts.
- “Users are the only one of the stakeholders (decision makers) in the process” Jh. Zimmerman
Prototyping
- Tremendously valuable strategy (one of the biggest skills you will get from the class)
- Rapid creation of the approximation of design idea
Getting feedback not just making artifact
Communicate with other stakeholders
Prototyping is a efficient strategy for dealing with things that are hard to predict
focus on GOALS
evolve the DESIGNS
Right prototype
- Not complete (in strategic way)
- Easy to change
- Ready for retire
What prototypes prototype?
|
Feel
|
What it might look like?
|
|
Implementation
|
What it might work like?
|
|
role
|
What might the experience be?
|
“The best way to have good idea is to have a lot of ideas.” Linus Pauling
Class structure
- Lab hours (2 hrs):
- 1st hour: group presentations, weekly milestones
- 2nd hour: workshops
- Practice hours (1 hr):
- Article discussions, case-studies
- Lectures (1 hr):
- First half – emphasis on the main concepts
- Second half – class activity on the given material
Storyboards isn’t about “pretty pictures”
It’s about communicating ideas
Storyboards Should Convey
- Setting
- People involved
- Environment
- Task being accomplished
- Sequence
- What steps are involved?
- What leads someone to use the app?
- What task being illustrated?
- Satisfaction
- What’s motivates people to use this system?
- What does it enable people to accomplish?
- What need does the system fill?
-
Benefits of Storyboarding
- Holistic focus: Helps emphasize how an interface accomplishes a task
- Avoids commitment to a particular user interface (no buttons yet)
- Helps get all stakeholders on the same page in terms of the goal
6 paper prototyping tips and tricks
- Keep all your materials in one place! Small interface widgets tend to get lost or damaged easily
- Work quickly and make reusable components (buttons, etc)
- If something is difficult to simulate (progress indicators, right mouse menus, hyperlinks), have user ask if it is available and then verbally describe interaction.
- Backgrounds (25cm x 29cm poster board) can be useful to contain
- Don’t be afraid to mix and match hardware and software! For instance, if size constraints are important, you might want to make a blinder using a photograph of the device that would be used and manipulate the prototype within the frame.
- When appropriate, add context by including familiar operating system components.
Get Creative with Materials
- Widgets: Paper, Cardboards, Transparencies
- Connectors: Tape, Glue, Rubber Cement
- Drawing: Pens, Pencils, Markers
- … and more
More materials
- Poster board, unlined index cards, a foam core are all useful depending on the size of your prototype
- Removable tape or restickable glue is useful for changing components quickly
- Transparency pens allow the user to input content – use a sheet of transparency paper for the input field
- Use wide-tipped pens and markers (think Sharpie) – smaller line widths can be difficult to see
- Use stacks of index cards to simulate tabbed dialog boxes.
Wizard of Oz technique
- Make an interactive app without (much) code
- Front end interface
- (remote) wizard controls user interface
- Makes sense when it’s faster/cheaper/easier than making real thing
- Get feedback from users people
- Hi-fidelity: users think it’s more real
- Low-fidelity: more license to suggest changes
Wizard-of-Oz prototyping . . .
simulates machine behavior with human operators
Aardvark
“Why start-ups Must Pay Attention to What’s Behind The Curtain”
– Venture Capital Dispatch WSJ
Making a Wizard powered prototype
- Map out scenarios and application flow
- What should happen in response to user behavior?
- Put together interface “skeleton”
- Develop “hooks” for wizard input
- Where and how the wizard will provide input?
- Selecting the next screen, entering text, entering a zone, recognizing speech, etc.
- Remember that later you’ll need to replace with computer
- Rehearse Wizard with a colleague
Running Wizard powered prototypes
- Practice with friends first
- Once you’re comfortable recruit ‘users’
- Two roles: facilitator and wizard
- Facilitator provides tasks (paper) and takes notes
- Wizard operates interface (more authentic if hidden or remote)
- User feedback can be:
- Think Aloud (speak freely as performing tasks)
- Retrospective (best when think aloud distracts)
- Heuristic evaluation (works with experts too)
- Debrief users (reveal wizard if needed)
Advantages of Wizards
- Fast and thus, cheaper and more iterative prototypes
- Creating multiple variations is easy
- More “real” than paper prototyping
- Identifies bugs and problems with current design
- Places the user at the center of development
- Can envision challenging-to-build application
- Designer learn by playing wizard
Disadvantages of Wizards
- Simulations may represent otherwise imperfect tech
- May simulate tech that doesn’t exist yet (and may never)
- Wizard require training and may be inconsistent
- Playing wizard can be exhausting
- Some features (and limitations) are difficult/impossible to simulate effectively
- May be inappropriate in some venues (e.g. home)
Benefits of Video Prototyping
- Cheap and Fast
- Great communication tools
- Helps achieve common ground
- Ideally portable and self-explanatory
- Can serve as a ‘spec’ for developers
- Ties interface designs to tasks
- Aligns and orients interface choices
- Makes sure you have a complete interface
- And that there’s nothing extra
What should the video show?
- Like a storyboard, the whole task, including motivation and success
- Establishing shots and narrative help
- Draw on tasks you’ve observed
- Illustrate important tasks your system enables
- Can help scope a minimum-viable-product
- Changes what design teams argue about (in a good way)
What are the steps?
- Start with an outline (or your storyboards)
- Fine to extemporize
- Equipment
- A camera. Could be a phone. Built-in laptop camera
- People
- a realistic location
- In general, focus on message more than production values
Considerations
- Can use audio or a silent movie with title cards (audio can be too wordy)
- Interface can paper, mockups, code or invisible (just showing the task)
- Can show both success and failure (of your interface and others)
- Edit as little as possible because editing is hugely time-consuming (in camera/pause editing is most efficient)
-
Creating and comparing alternatives
- Quantity or Quality?
“The works of highest quality were all produced by the group being graded for quantity. It seems that while the “quantity” group was busily churning out piles of work - and learning from their mistakes - the “quality” group had sat theorizing about perfection, and in the end had little more to show for their efforts than grandiose theories and a pile of dead clay.” (Bayles and Orland, 2001)
Benefits of sharing multiple
- More individual exploration
- More features sharing
- More conversational turns
- Better consensus
- Increase in group rapport
Alignment guides the eye, reducing clutter
- Avoid slight misalignments
- they undermine your ability to beacon organization.
- We ‘automatically’ notice patterns
- and deviations
- So when you deviate from a pattern
- do so strategically
- And use visual proximity and scale
- to convey semantic information
A brief word on color
- Pay attention to it
- Design in grayscale first
- Keep luminance values from grayscale when moving to color
Grids: to learn more …
- Kevin Mullet and Darrel Sano, Designing Visual Interfaces
- Luke Wroblewski, Web Form Design
- Jan Tschichold, The New Typography
How can you detect poor scent?
- Flailing
- Low confidence
- Back button
Low-scent navigation
- Surprising categories
- Short links
- Hidden navigation
- Icons provide little additional information.
Icons help when …
- They facilitate repeat recognition
- When you know what something looks like but not what it’s called
- Good redundant coding can help
Improving scent: multi-word links
- With specific, recognizable terms
- Trigger words, not “clever” terms
- This also helps accessibility
Prime real estate
- Above the fold
- Where people expect
- Where other pages put similar content
- Not where ads usually
Whitespace conveys grouping
“Some space might be narrow so that other space may be wide, and some space must be emptied so that other space may be filled.”
Use size contrasts to indicate hierarchy
“Information consists of differences that make a difference.”
Three basic tools of visual design
- Typography
- Layout
- Color
“Minute to learn and lifetime to master”
Challenges
- Individual differences dwarf manipulation effects
- i.e. some people read faster than others. If there is an effect, it’s very small.
- Confound: Reading requires familiarity
- Dependent Variable? Speed? Comprehension?
“Legibility, in practice, amounts simply to what one is accustomed to” – Eric Gill, 1931
No Robust Evidence for Serif Hypothesis
“What initially a neat dichotomous question of serif vs sans serif has resulted in a body of research consisting of weak claims and counter-claims, and study after study with findings of ‘no difference’. Is it the case that more than one hundred years of research has marred by repeated methodological flaws, or are serifs simply a typographical ‘red herring’?”
To improve typographical eye
- Use typefaces in multiple places to see its range
- Display the same text with different typefaces to change its effect
Multiple ways to evaluate
- Empirical assess with real users
- Formal methods and formulas to calculate measures
- Automated software measures
- Critique: expertise and heuristic feedback
When to get design critique?
- Before user testing: Don’t waste users on the small stuff. Critique can identify minor issues that can be resolved before testing, allowing users to focus on big issues.
- Before redesigning: Don’t throw out the baby with the bathwater: critique can help you learn what works and what should change.
- When you know there are problems, but you need evidence. Perhaps you’ve received complaints from customers or found yourself stumbling around your site. Critique can help you articulate problems and provide you with ammunition for redesign.
- Before release: smooth off rough edges.
Heuristic Evaluation
- Developed by Jacob Nielsen
- Helps find usability problems in a design
- Small set (3-5) of evaluators to examine UI
- Independently check for compliance with usability principles (“heuristics”)
- Different evaluators will find different problems
- Evaluators only communicate afterwards:
- Finding are then aggregated
- Can perform on working UI or sketches
Nielsen’s Ten Heuristics
- Visibility of System Status
- Match between System and World
- User Control & Freedom
- Consistency & Standards
- Error Prevention
- Recognition Rather than Recall
- Flexibility & Efficiency of Use
- Aesthetic & Minimalist Design
- Help Users Recognize, Diagnose, & Recover from Errors
- Help and Documentation
Evaluators’ Process
- Step through design several times
- Examine details, flow and architecture
- Consult list of usability principles
- … and everything else that comes to mind
- Which principles?
- Nielsen’s “heuristics”
- Category-specific heuristics from
- E.g. Design goals, competitive analysis, existing design
- User violations to redesign/fix problems
Why Multiple Evaluators?
- No evaluator finds everything
- Some find more than others
Heuristic Eval: Cost-effective
- In one case: benefit-cost ratio of 48
- Estimated benefit $500,000; cost $10,500
- Value of each problem ~15K
- How might we calculate this value?
- In-house -> productivity; open market -> sales
- Severe problems found more often
- Single evaluator achieves poor results
- Only finds 35% of usability problems
- 5 evaluators find ~75% of problems
Heuristics vs User Testing
- Heuristic Evaluation often faster:
- 1-2 hours each evaluator
- HE presets come pre-interpreted
- User testing is more accurate (by def.)
- Takes into account actual users and tasks
- HE may miss problems & find “false positives”
- Valuable to alternate methods
- Find different problems
- Don’t waste participants
Phases of Heuristic Evaluation
- 1. Pre-evaluation training: give evaluators needed domain knowledge and information on the scenario
- 2. Evaluation: individuals evaluate and then aggregate results
- 3. Severity rating: determine how severe each problem is (priority). Can do first individually and the as a group.
- 4. Debriefing: review with design team
How-to: Heuristic Evaluation
- At least two passes for each evaluator
- First to get feel for flow and scope of system
- Second to focus on specific elements
- If system is walk-up-and-use or evaluators are domain experts, no assistance needed
- Otherwise might supply evaluators with scenarios
- Each evaluator produces list of problems
- Explain why with reference to heuristic or other information
- Be specific and list each problem separately
How-to: Heuristic Evaluation
- Why separate listings for each violation?
- Risk of repeating problems aspect
- May not be possible to fix all problems
- Where problems may be found
- Single location in UI
- Two or more locations that need to be compared
- Problem with overall structure of UI
- Something is missing
- Ambiguous with early prototypes; clarify in advance
- Sometimes features are implied by design docs and just haven’t been “implemented” – relax on those.
Severity Rating
- Independently estimate after review
- Allocate resources to fix problems
- Estimate need for more usability efforts
- Severity combines
- Frequency
- Impact
- Persistence
Severity ratings
- 0 – don’t agree that this is a usability problem
- 1 – cosmetic problem
- 2 – minor usability problem
- 3 – major usability problem; important to fix
- 4 – usability catastrophe; imperative to fix;
Severity Ratings Example
- Issue: unable to edit one’s weight
- Severity: 2
- Heuristic violated: User control and freedom
- Description: when you open the app for the first time, you have to enter your weight, but you cannot update it. It could be useful if you mistyped your weight, or if one year or two after the first use of the app, your weight has changed.
Debriefing
- Conduct with evaluators, observers, and development team members
- Discuss general characteristics of UI
- Suggest potential improvements to address major usability problems
- Dev. team rates effort to fix
- Brainstorm solutions
HEURISTICS
- Show system status
- Familiar metaphors and language
- Control and freedom
- Consistency
- Error prevention
- Recognition over recall
- Flexibility and efficiency
- Aesthetic & minimalistic design
- Recognize, diagnose & recover errors
- Help
Show system status: Time
- Feedback depends on response time:
- < 1s: just show outcome
- ~ 1s: feedback that activity is underway
- >> 1s: show functional progress; time
Show: space
- Feedback above is telling I’m out of space in Gmail account.
Show: change
- You’ve changed doc, want to save?
Show: next steps
- It’s important for user to know what is actionable for the next. They don’t see the problem, but have a solution provided already.
- Answers already in the message.
Problem Solving as Representation
“Solving a problem simply means representing it so as to make the solution transparent”
- Herbert Simon, The Sciences of the Artificial
Working memory
- Capacity: 2 +/- 2 (don’t require your users to remember)
Getting Things Done
- Task management system
- Whenever something comes to mind, just write it down immediately.
When interfaces help people distribute cognition, it can . . .
- Encourage experimentation
- Scaffold learning and reduce errors through redundancy
- Show (only) differences that matter
- Convert slow calculation into fast perception
- Support chunking, especially by experts
- Increase efficiency
- Facilitate collaboration
A good representation
. . . shows all of the relevant information, and nothing else.
Should enable:
- Comparison
- Exploration
- Problem solving