Task Analysis

1
Task Analysis

• Whats the goal?

2
Agenda

• Task Analysis
• Overview, utility
• Types of task analysis
• Sources and use

3
Task Analysis

• Analyzing and describing how people do their
  jobs/work
• -gt Go to their environment
• Examine users tasks to better understand what
  they need from interface and how they will use it

4
Components

• Three key components to include in discussing how
  people work
• Activities
• Artifacts
• Relations
• Dont 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.

5
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)

6
Input Output

• Gather data
• Documentation
• Interviews
• Observation
• Surveys/questionnaires
• Automatic data recording/tracking
• Represent Data
• Lists, outlines, matrices
• Narratives
• Hierarchies Networks
• Flow charts

7
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

8
Data 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

Must include 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

10
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

13
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 wont/cant use it,
  dont ask it.

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DGT Think-aloud

• Questions Answers, contd
• 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.

15
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
• 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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Task Outline

• Using a lawnmower to cut grass
• 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

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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
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Example Task Clusters

• Fixed sequence
• Optional tasks
• Waiting events
• Cycles
• Time-sharing
• Discretionary

22
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

23
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?
Document
Manual Operation
Y
Input
N
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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Upcoming

• Predictive evaluation (w/o users)
• Discount usability testing
• Cognitive models
• GOMS, CCT
• Context-based approaches
• Interpretive evaluation
• Observation, ethnography