Transcript Slides for Lecture 2

IAT 334
Interface Design
Task Analysis
______________________________________________________________________________________
SCHOOL OF INTERACTIVE ARTS + TECHNOLOGY [SIAT] | WWW.SIAT.SFU.CA
Jan 13, 2011
IAT 334
1
Agenda
 Task
Analysis
 Evaluation
 Predictive evaluation
– Heuristic evaluation
– Discount usability testing
– Cognitive walkthrough
Jan 13, 2011
IAT 334
2
Task Conformance
 Task
coverage
– Can system do all tasks of interest?
 Task
adequacy
– Can user do tasks?
– Does system match real-world tasks?
Jan 13, 2011
IAT 334
3
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
Jan 13, 2011
IAT 334
4
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
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…
Jan 13, 2011
IAT 334
6
Task Analysis
 Broad
Focus
 Observe users of current system(s)
 Generate requirements
– Hierarchical task analysis
– Knowledge-based task analysis
– Entity-Relationship model
Jan 13, 2011
IAT 334
7
Data Gathering Techniques
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
1.
Jan 13, 2011
IAT 334
8
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
Jan 13, 2011
IAT 334
9
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
Jan 13, 2011
IAT 334
10
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
Jan 13, 2011
IAT 334
11
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
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
Jan 13, 2011
IAT 334
13
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
Jan 13, 2011
IAT 334
14
More!

Often used in addition:
4.
5.
6.
7.
8.
Jan 13, 2011
Surveys & Questionnaires
Focus Groups & Expert Debriefing
Competitive Product Review
Documentation mining
Data logging
IAT 334
15
Existing System
 Usually
task analysis involves an
examination of an existing system,
process or practice
 Watch
Jan 13, 2011
what they do and how they do it
IAT 334
16
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.
Jan 13, 2011
IAT 334
17
Questionnaires
 Likert
scale common
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
Disagree
2. I found the computer agent to be intrusive.
1-----2------3------4------5------6------7
Strongly
Disagree
3. I found the computer agent's help to be distracting.
Jan 13, 2011
Strongly
Agree
IAT 334
Strongly
Agree
1-----2------3------4------5------6------7
Strongly
Disagree
Strongly
18
Agree
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
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

Jan 13, 2011
IAT 334
20
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)
Jan 13, 2011
IAT 334
21
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
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
No Existing System
 Gather
documents, talk with
knowledgeable people, etc.
 Can
still be useful to help generate
requirements
Jan 13, 2011
IAT 334
24
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?
Jan 13, 2011
IAT 334
25
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
Describe Tasks
1.
2.
3.
Task Outlines
Narratives
Hierarchies & Network Diagrams
– Hierarchical Task Analysis (HTA)
– Entity-Relationship Diagrams
4.
5.
Flow Charts
Card Sorting
Jan 13, 2011
IAT 334
27
1. Task Outline
Using a lawnmower to cut grass
Step 1. Examine lawn
a.
b.
Make sure grass is dry
Look for objects laying in the grass
Step 2. Inspect lawnmower
a.
Check components for tightness
1)
2)
3)
4)
5)
b.
Check engine oil level
1)
2)
3)
4)
5)
Jan 13, 2011
Check that grass bag handle is securely fastened to the grass bag support
Make sure grass bag connector is securely fastened to bag adaptor
Make sure that deck cover is in place
Check for any loose parts (such as oil caps)
Check to make sure blade is attached securely
Remove oil fill cap and dipstick
Wipe dipstick
Replace dipstick completely in lawnmower
Remove dipstick
Check that oil is past the level line on dipstick
IAT 334
28
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
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
Jan 13, 2011
IAT 334
30
Jan 13, 2011
IAT 334
31
Hierarchical Task
Decomposition
 Decompose
task into
– Subtasks
• Multiple levels
– Plans describing ordering and conditions
Jan 13, 2011
IAT 334
32
Common Plans
 Fixed
sequence
 Optional tasks
 Waiting for events
 Cycles
 Time-sharing -- parallel
 Discretionary
Jan 13, 2011
IAT 334
33
Entity-Relationship
 Object-based
methodology, with a real
stress on relationship between objects
and actions
 Involves
– Concrete objects
– Actors
– Composite objects
Jan 13, 2011
IAT 334
34
Example
 Task:
Develop design for final project
– Objects
- Pens, paper, drawing tools, etc.
– Actors
- Mary, Bob, Sally
– Composite objects
- The “team”
Jan 13, 2011
IAT 334
35
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
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
Jan 13, 2011
IAT 334
37
Methodology
 Sample:
– Get 3x5 cards
– Put different object/action on each
– Don’t worry about repetition at this point!
– Group into piles, subpiles, etc.
Jan 13, 2011
IAT 334
38
Utility
 This
type of task analysis can be very
useful when you’re writing a manual or
some documentation
– Taxonomy --- Document sections
Jan 13, 2011
IAT 334
39
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
Jan 13, 2011
IAT 334
40
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
Jan 13, 2011
IAT 334
41
Summary:
Data Gathering Techniques
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
1.
Jan 13, 2011
IAT 334
42
Summary:
Describe Tasks
1.
2.
3.
Task Outlines
Narratives
Hierarchies & Network Diagrams
– Hierarchical Task Analysis (HTA)
– Entity-Relationship Diagrams
4.
5.
Flow Charts
Card Sorting
Jan 13, 2011
IAT 334
43