User Interface Design

1. Jan 13, 2011 IAT 334 1
IAT 334
Interface Design
Task Analysis
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SCHOOL OF INTERACTIVE ARTS + TECHNOLOGY [SIAT] | WWW.SIAT.SFU.CA

2. Jan 13, 2011 IAT 334 2
Agenda
 Task Analysis
 Evaluation
 Predictive evaluation
– Heuristic evaluation
– Discount usability testing
– Cognitive walkthrough

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Task Conformance
 Task coverage
– Can system do all tasks of interest?
 Task adequacy
– Can user do tasks?
– Does system match real-world tasks?

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Task Analysis
 Analyzing how people do their jobs
– Go to their environment
– Learn about, analyze and describe their tasks
 Examine users’ tasks to better understand
what they need from interface and how
they will use it

5. Task Analysis
 Gather data about what users need to do
or accomplish
…then…
 Represent data for interpretation and use
in design decisions
Jan 13, 2011 IAT 334 5

6. Information to be Gathered
 Information about users
 Description of environment
– where the tasks will be performed
 Major goals of the job
– what will result in a successful end state?
 User preferences & needs
– before they even start: coffee, pen,
notebook, log sheets…
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7. Jan 13, 2011 IAT 334 7
Task Analysis
 Broad Focus
 Observe users of current system(s)
 Generate requirements
– Hierarchical task analysis
– Knowledge-based task analysis
– Entity-Relationship model

8. Data Gathering Techniques
1. Observation
2. Interviews & Contextual Inquiry
3. Ethnography
also…
4. Surveys & Questionnaires
5. Focus Groups & Expert Debriefing
6. Competitive Product Review
7. Documentation mining
8. Data logging
Jan 13, 2011 IAT 334 8

9. Information to be Gathered
 Tasks & Subtasks:
– Physical
– Cognitive
– Communication
 Conditions under which these tasks are done
 Results/outcomes of tasks
 Requirements to perform task:
– Information
– Communication with others
– Equipment
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10. 1. Observation
 Watch users do what they do
– Typically from a distance
 Record with videotape
– May require coding video later
 Take lots of notes, sketches
 Focus on specific task-relevant behaviors
in notes, but later convert to abstract
subtasks
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11. 2. Interviews
 Engage the user more than just watching
 Structured interviews
– Efficient, but requires training
 Unstructured
– Inefficient, but requires no training
 Semi-structured
– Good balance
– Often appropriate
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12. Semi-Structured Interviews
 Predetermine data of interest
 Plan for effective question types
– How do you perform task x?
– Why do you perform task x?
– What information do you need to…?
– Who do you need to communicate with to…?
– What do you use to…?
– What happens after you…?
– What is the result or consequence of NOT…?
Jan 13, 2011 IAT 334 12

13. 3. Ethnography
 Deeply contextual inquiry
– “Wallow in the data”
 “Live among” the users
 Understanding the full complexity of
behavior, in its complete social context
 Note: Techniques based in sociology and
anthropology--the study of humans
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14. Comment
 Techniques 1-3 are similar, but differ in
how “plugged in” or engaged the observer
gets
 There are Pros and Cons of all these
techniques
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15. More!
 Often used in addition:
4. Surveys & Questionnaires
5. Focus Groups & Expert Debriefing
6. Competitive Product Review
7. Documentation mining
8. Data logging
Jan 13, 2011 IAT 334 15

16. Jan 13, 2011 IAT 334 16
Existing System
 Usually task analysis involves an
examination of an existing system,
process or practice
 Watch what they do and how they do it

17. 4. Surveys & Questionnaires
 Subjective answers in a quantitative format
– What does this mean?
 Questions:
– Exploratory vs. confirmatory
– Open-ended vs. categorical (exhaustive)
– NB: If you ask it, use it. If you won’t/can’t use it,
don’t ask it.
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18. Questionnaires
 Likert scale common
Jan 13, 2011 IAT 334 18
Evaluation Questionnaire
Please complete the following questionnaire by indicating how strongly you agree or disagree with the
following statements. Your responses will be kept confidential and will be used only for improving the
interface that you worked with in this experiment.
1. I felt that the computer agent’s help was worthwhile. 1-----2------3------4------5------6------7
Strongly Strongly
Disagree Agree
2. I found the computer agent to be intrusive. 1-----2------3------4------5------6------7
Strongly Strongly
Disagree Agree
3. I found the computer agent's help to be distracting. 1-----2------3------4------5------6------7
Strongly Strongly
Disagree Agree

19. Typical Questions
 Rank the importance of each of these tasks
(give a list of tasks)
 List the four most important tasks that you
perform (this is an open question)
 List the pieces of information you need to have
before making a decision about X, in order of
importance
 Are there any other points you would like to
make? (open-ended opinion question; good way
to end)
Jan 13, 2011 IAT 334 19

20. 5. Focus Groups
 Structured Interview with groups of individuals
– 3 to 10 persons
– Use several different groups with different roles or
perspectives
– Manage the interaction
• Avoid few people dominating the discussion
 Focus on preferences and views, not
performance
 Relatively low cost, quick way to learn a lot
 Audio or video record, with permission
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21. 6. Competitive Products
 Looking for both good and bad ideas
– Functionality
– UI style
 Why are they successful or unsuccessful?
 What does successful really mean?
– (Note: Successful does not equal usable)
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22. 7. Document Mining
 Documentation
– Often contains description of how the tasks
should be done
– Standards docs
– Manuals
– Histories
– Best Practices
Jan 13, 2011 IAT 334 22

23. 8. Data Logging
 Automatically tracking:
– Keystroke/mouse clicks
– Timers
– Logs of transactions
– Physical location/movement trackers
• Cell phones
• GPS
Jan 13, 2011 IAT 334 23

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No Existing System
 Gather documents, talk with
knowledgeable people, etc.
 Can still be useful to help generate
requirements

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Task Analysis Focus
 Not on internal cognitive state of user
(more on that in the near future)
 Focus on observable behaviors
– Observe users, what they do, and how they
do it
– What are the practices, methods, steps,
objects, …, used?

26. Now that you have observed…
 You have piles of notes, hours of video,
surveys up to here…
 How can you digest and represent the
data, to turn it into information?
Jan 13, 2011 IAT 334 26

27. Describe Tasks
1. Task Outlines
2. Narratives
3. Hierarchies & Network Diagrams
– Hierarchical Task Analysis (HTA)
– Entity-Relationship Diagrams
4. Flow Charts
5. Card Sorting
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28. 1. Task Outline
Using a lawnmower to cut grass
Step 1. Examine lawn
a. Make sure grass is dry
b. Look for objects laying in the grass
Step 2. Inspect lawnmower
a. Check components for tightness
1) Check that grass bag handle is securely fastened to the grass bag support
2) Make sure grass bag connector is securely fastened to bag adaptor
3) Make sure that deck cover is in place
4) Check for any loose parts (such as oil caps)
5) Check to make sure blade is attached securely
b. Check engine oil level
1) Remove oil fill cap and dipstick
2) Wipe dipstick
3) Replace dipstick completely in lawnmower
4) Remove dipstick
5) Check that oil is past the level line on dipstick
Jan 13, 2011 IAT 334 28

29. 2. Narratives
 Describe tasks in sentences
 Often expanded version of task outline
 More effective for communicating general
idea of task
 Not effective for details
 Not effective for branching tasks
 Not effective for parallel tasks
Jan 13, 2011 IAT 334 29

30. 3. Hierarchies & Networks
 Hierarchical Task Analysis (HTA)
– Graphical notation & decomposition of tasks
– Tasks as sets of actions
– Tasks organized into plans (describes sequence)
 Network / Entity-Relationship Diagrams
– Objects/people with links to related objects
– Links described functionally and in terms of strength
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Hierarchical Task
Decomposition
 Decompose task into
– Subtasks
• Multiple levels
– Plans describing ordering and conditions

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Common Plans
 Fixed sequence
 Optional tasks
 Waiting for events
 Cycles
 Time-sharing -- parallel
 Discretionary

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Entity-Relationship
 Object-based methodology, with a real
stress on relationship between objects
and actions
 Involves
– Concrete objects
– Actors
– Composite objects

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Example
 Task: Develop design for final project
– Objects - Pens, paper, drawing tools, etc.
– Actors - Mary, Bob, Sally
– Composite objects - The “team”

36. 4. Flow Charts
 Flow Chart of Task Steps
– Combines Entity-relationship (network) with
sequential flow, branching, parallel tasks.
– Includes actions, decisions, logic, by all
elements of the system
– Abstracted
– Mature, well-known, good tools
Jan 13, 2011 IAT 334 36

37. Jan 13, 2011 IAT 334 37
5. Knowledge-based
Analysis
 List all objects and actions involved in a
task, then build a taxonomy of them
 Often times, work with domain expert to
get help

38. Jan 13, 2011 IAT 334 38
Methodology
 Sample:
– Get 3x5 cards
– Put different object/action on each
– Don’t worry about repetition at this point!
– Group into piles, subpiles, etc.

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Utility
 This type of task analysis can be very
useful when you’re writing a manual or
some documentation
– Taxonomy --- Document sections

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Methodology
 Often list attributes, actions of objects
Object: pen simple
Attribute:
color: red
writing: on/off
Object: Mary actor
Actions:
M1: make a sketch
M2: organize meeting

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Use
 Produce documentation
– Training, manuals, tutorials
 Requirements capture and system design
– Helps you define requirements document
– Helps decide what should be included
 Helps interface design
– Hierarchical breakdown might feed menu
design

42. Summary:
Data Gathering Techniques
1. Observation
2. Interviews & Contextual Inquiry
3. Ethnography
also…
4. Surveys & Questionnaires
5. Focus Groups & Expert Debriefing
6. Competitive Product Review
7. Documentation mining
8. Data logging
Jan 13, 2011 IAT 334 42

43. Summary:
Describe Tasks
1. Task Outlines
2. Narratives
3. Hierarchies & Network Diagrams
– Hierarchical Task Analysis (HTA)
– Entity-Relationship Diagrams
4. Flow Charts
5. Card Sorting
Jan 13, 2011 IAT 334 43