Transcript User Modeling - Gunadarma University

Task Analysis
• Analyzing and describing how people do
their jobs/work
 -> Go to their environment
• Examine users’ tasks to better understand
what they need from interface and how
they will use it
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Components
• Three key components to include in discussing
how people work
 Activities
 Artifacts
 Relations
• Don’t just focus on computer system artifacts
and interactions
• Study related processes and objects in the
environment that people may use and involve
 Example: office env---papers, whiteboards, etc.
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Task Analysis Focus
• Focus on observable behaviors
 What are the practices, methods, steps,
objects, …, used?
• Observe users, what they do, less so how
they do it
• Not on internal cognitive state of user
(more on that next week)
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Input & Output
• Gather data:
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Documentation
Interviews
Observation
Surveys/questionnaires
Automatic data recording/tracking
• Represent Data:
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Lists, outlines, matrices
Narratives
Hierarchies & Networks
Flow charts
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Data 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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Data to be Gathered …
• Tasks & Subtasks:
 Physical
 Cognitive
 Communication
• Conditions under which these tasks are done
• Results/outcomes of tasks
• Requirements to perform task:
Must include
 Information
 Communication with others
 Equipment
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Should include
Could include
Exclude
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Data Gathering Tools: Docs
• Documentation
 Often contains description of how the tasks should be
done (rather than how they are currently being done)
 Standards
 Manuals
 Histories
 Best Practices
• Domain Expert Description
 Expert describes how process should work, how tasks
should be done
 “Knowledge-based” discovery
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DGT: Interviews
• Interviews:
 Structured
Efficient
Require training
 Unstructured
Inefficient
No training
 Semi-structured
Good balance
Often appropriate
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Semi-structured
Interviews
• Predetermine data of interest
• Plan for effective question types
How do you perform task x?
Why do you perform task x?
Under what conditions do you perform task x?
What do you do before you perfom…?
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…?
What is the result or consequence of NOT…?
 See: Gordon & Gill, 1992; Graesser, Lang, & Elofson,
1987
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DGT: Observation
• Observation
 In situ, watch users do what they do
 Record with videotape
To watch later, or again
 Take lots of notes, sketches
 May require coding the video later
 Focus on specific task-relevant behaviors in
notes, but later convert to abstract subtasks
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DGT: Questions
• Questions & Answers
 Questionnaires
Exploratory vs. confirmatory
Open-ended vs. categorical (exhaustive)
What do you need to perform..? (list)
Which of the following is most important to perform…?
(select)
If you ask it, use it. If you won’t/can’t use it, don’t
ask it.
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DGT: Think-aloud
• Questions & Answers, cont’d…
 Think-aloud protocol
Person talks about what they are doing, while they
are doing it (or just before or after)
Observer can ask probe questions
Why did you just do that?
 Note: Probe questions affect performance, as
does thinking aloud.
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DGT: Logging
• Automatic tracking
 Keystroke/mouse click monitoring
 Timers
 Logs
 Physical location/movement trackers
Cell phones
Aware Home
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Representing Data: Outlines
• Lists, outlines, matrices
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Use expanding/collapsing outline tool
Add detail progressively
Know in advance how much detail is enough
Can add linked outlines for specific subtasks
 Good for sequential tasks
 Does not support parallel tasks well
 Does not support branching well
 Example, next slide
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Using a lawnmower to cut grass
Task Outline
Step 1. Examine lawn
Make sure grass is dry
Look for objects laying in the grass
Step 2. Inspect lawnmower
Check components for tightness
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
Check engine oil level
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
…
RD: Narratives
• Narratives
 Describe tasks in sentences
 Often expanded version of list or outline
 More effective for communicating general
idea of task
 Not effective for details
 Not effective for branching tasks
 Not effective for parallel tasks
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RD: Hierarchies
• Hierarchical Task Analysis (HTA)
 Graphical notation & decomposition of tasks
 Tasks as sets of actions
 Tasks organized into plans
Clusters of subtasks with a preferred order and
prerequisite conditions
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HTA
Example Task Clusters
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Fixed sequence
Optional tasks
Waiting events
Cycles
Time-sharing
Discretionary
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RD: Networks
• Network / Entity-Relationship Diagrams
 Objects/people with links to related objects
Stress relationship between objects and actions
 Links described functionally and in terms of
strength
Task: Develop design for final project
objects - pens, paper, drawing tools, etc.
actors - Mary, Bob, Sally
composite objects - the “team”
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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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RD: 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
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Flow Chart
Start
Continue?
Y
Document
Manual
Operation
N
Input
Display
End
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Summary of Task Analysis
• Determine the data you need
• Gather it using various appropriate
methods and techniques
• Represent the tasks and subtasks, plus
other related information
• Use this data to improve design
• Note: Be efficient!
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