Task Analysis

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Task Analysis
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• Task analysis is the process of analyzing the way
  people perform their jobs the things they do,
  the things they act on and the things they need
  to know.

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What is Task Analysis?

• Technique
• Lists tasks to be carried out
• Lists actions user carries out in performing a
  task
• Things user does, acts upon, needs to know
• Focuses on the user
• Focuses on interaction

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Usability Methods Toolbox
http//jthom.best.vwh.net/usability
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• contextual inquiry
• ethnographic study / field observation
• interviews and focus groups
• surveys
• questionnaires
• jounaled sessions
• self-reporting logs
• screen snapshots

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Approaches

• Task decomposition
• Looks at the way a task is split into subtasks,
  and the order in which they are performed

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Hierarchical Task Analysis (HTA)

• Task decomposition
• Split into subtasks - subdivision no longer
  needed
• Plans to describe order and conditions
• Text and diagrams

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• Generating the hierarchy 
•  
•        ?  get list of tasks
•        ?  group tasks into higher level tasks
•        ?  decompose lowest level tasks further 
•          

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Hierarchy Description

• 0. in order to clean the house
• 1. get the vacuum cleaner out
• 2. get the appropriate attachments
• 3. clean the rooms
•                               3.1. clean the hall
•                               3.2. clean the
  living rooms
•                               3.3. clean the
  bedrooms
• 4. empty the dust bag
• 5. put vacuum cleaner and attachments away 

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Hierarchy Description
GOAL

• 0. in order to clean the house
• 1. get the vacuum cleaner out
• 2. get the appropriate attachments
• 3. clean the rooms
•                               3.1. clean the hall
•                               3.2. clean the
  living rooms
•                               3.3. clean the
  bedrooms
• 4. empty the dust bag
• 5. put vacuum cleaner and attachments away 

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Hierarchy Description

• 0. in order to clean the house
• 1. get the vacuum cleaner out
• 2. get the appropriate attachments
• 3. clean the rooms
•                               3.1. clean the hall
•                               3.2. clean the
  living rooms
•                               3.3. clean the
  bedrooms
• 4. empty the dust bag
• 5. put vacuum cleaner and attachments away 

SUBTASK
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Hierarchy Description

• 0. in order to clean the house
• 1. get the vacuum cleaner out
• 2. get the appropriate attachments
• 3. clean the rooms
•                               3.1. clean the hall
•                               3.2. clean the
  living rooms
•                               3.3. clean the
  bedrooms
• 4. empty the dust bag
• 5. put vacuum cleaner and attachments away 

Further SUBTASKS
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Plans

• Explanation for each step
• Fixed sequence - parts always done
• Choice
• Waiting for events
• Cycles - repetition
• Time-sharing - done at same time
• Discretionary - optional
• Mixture of all above

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Make Plans

• Plan 0 do 1 - 2 - 3 - 5 in that order.
• when the dust bag gets full do 4
•  Plan 3 do any of 3.1, 3.2 or 3.3 in any order
  depending on which rooms need cleaning 

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Stopping rules

• How do we know when to stop?
•                   Is empty the dust bagsimple
  enough?
•                   Purpose expand only relevant
  tasks
•                   Motor actions lowest sensible
  level

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Upon completion

• Check for errors
• Check for omissions

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ExampleMaking tea the English way!

• 0. Make a cup of tea
• 1. Boil water in kettle
• 2. Fill teapot
• 3. Empty teapot
• 4. Make tea in pot
• 5. Pour tea
• 5.1 put milk in cup
• 5.2 fill cup with tea
• 5.3 add sugar to taste

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Plans

• Plan 0
• Do 1
• At the same time, if pot is full 2
• Then 3 -4
• After four or five mins. 5

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ExampleMaking tea the English way!

• 0. Make a cup of tea
• 1. Boil water
• 2. Fill pot
• 3. Empty pot
• 4. Make tea in pot
• 5. Pour tea
• 5.1 put milk in cup
• 5.2 fill cup with tea
• 5.3 add sugar to taste

• Plan 0
• Do 1
• At the same time,
• if pot is full 2
• Then 3 -4
• After four or five mins. 5

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ExampleMaking tea the English way!

• 0. Make a cup of tea
• 1. Boil water
• 2. Fill pot
• 3. Empty pot
• 4. Make tea in pot
• 5. Pour tea
• 5.1 put milk in cup
• 5.2 fill cup with tea
• 5.3 add sugar to taste

• Plan 5
• 5.1 - 5.2
• If desired 5.3

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Diagram

• 5.1

NO
For each guest
5.2
Empty cups?
5.3
YES
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0 Make cups of tea
Plan 0 do 1 at the same time, if pot
full 2 then 3 -4 After 4 -5 min do 5
1 Boil water
2 Empty pot
3 Make a pot
4 Wait 4 or 5 minutes
5 Pour tea
Plan 1 1.1 - 1.4 When kettle boils 1.5
Plan 3 3.1 - 3.3
3.1 warm pot
3.2 Put leaves in pot
3.3 Pour in boiling water
1.1 Fill kettle
1.2 Put kettle on stove
1.3 Turn on flame
1.4 Wait for kettle to boil
1.5 Turn off flame
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In-Class

• Define critical tasks
• Create an HTA.
• Deliverables
• Textual HTA
• Include Plans
• Diagrammatical HTA