This Week#

• User Task analysis
• User Object Modeling
• Mental Models

Further reading:
Redmond-Pyle & Moore, Sections 3.3, Chapters 6, 7

The Guide Method#

What is a user task and Modeling?#

Example of a task (Send a message)

• Modeling (Processes of sending message)
  • Use mobile
  • Open message application
  • Type a message
  • Send it
• To accomplish goal, Each Task should be
  • Meaning full
  • Associated with a goal
  • Identifiable by a user

The Aim of Modeling User Tasks#

Modeling user tasks enable us to analyze the tasks and conceptual objects; this then provides useful information for the design of the interface.

The Objectives of Task Analysis#

• Understand User Goals: helps in identifying and understanding the goals users want to achieve while interacting with a system
• Analyze User Tasks: involves breaking down complex tasks into smaller, manageable steps
• Create Task Models: forms the basis for creating task models, which are graphical representations of tasks, actions, and interactions
• Develop Task Scenarios: Task scenarios are detailed narratives describing specific situations in which users interact with a system to accomplish tasks.

Task Scenarios#

Task scenarios are detailed descriptions of a specific situation or context in which a user might interact with a product, service, or system (initial circumstances, input, subtasks).

• A scenario could include typical data; it may, include exceptions. It can be thought of as a test case for a task, including
  • a situation or set of circumstances for a task
  • a script describing how a user performs a task

Task Analysis#

• Task Analysis is
  • the study of what a user will want to do with the system
  • documentation of the information and control facilities used to carry out a task
  • a methodology to help the analyst collect and organize information then use it to make design decisions.
• Relevant information about each task may include:
  • who performs it
  • frequency
  • average performance time
  • user error frequency
  • notes about the context in which the task is performed

Task Models#

This an abstract model of the structure of the tasks that users carry out. Two well-known task models are
GOMS
   Goals, Operators, Methods, Selection Rules
Task Hierarchy Diagram
   - goals, tasks, operations, plans
   - hierarchies, redescription, stopping rules

Both models
   - have different ways of breaking large tasks down into smaller tasks
   - ultimately identify the conceptual actions and conceptual objects of the system

Task Hierarchy Diagrams#

Notes:

• The structure of the tree indicates how one task is  broken up into subtasks
• There are notations for indivisible sub-tasks, and for indicating which sub-task has its own diagram.
• The diagrams can be added to indicate the order of  tasks (if not obvious from the diagram) or conditions under which the tasks are performed

Hierarchy Task Analysis#

Task Analysis-Example#

Scenario: Online Grocery Shopping Task Analysis Background: Sarah, a working professional, wants to buy groceries online due to her busy schedule. She has limited time and wants to efficiently complete her grocery shopping without any hassle

Task Analysis:

Why use Task Analysis?#

• To ensure efficient and effective integration of the human element into system design
• To more clearly establish the relationship between
  • human requirements & limitations
  • design preferences & constraints
• To avoid the design of sub-optimal systems

The process of Task Analysis#

1. Define the Task

• Identify the task
• Understand the context

2. Identify the Users

• Define the user demographics:
• Identify user goals

3. Observe and Document

• Observe users
• Take notes

4. Decompose the Task

• Break down the task
• Hierarchical breakdown

5. Create Task Flow Diagrams

• Visual representation
• Annotate the diagram

6. Analyze Pain Points

• Identify challenges
• Determine causes

7. Validate with Users

• Usability testing
• Iterative process

8. Document Findings

• Create a task analysis report
• Visual aids

9. Iterate and Improve

We have learnt….#

✅What is User Task?
✅User Task Analysis?
✅Task Analysis Models?
✅Examples of Task Analysis?
✅Processes of Task Analysis

The Guide Method#

User Object-User object Modeling#

✅What is a User Object?
✅Characteristics of User object?
✅User Object Modeling?
✅Benefits of User Object Modeling?

What is a User Object?#

Examples of user objects in different software:

• A business system object (Invoice, Customer)
• A computer system object (Printer) .
• A container object (folder/directory, list)
• In LMS (student, student number, timetable,  module, module registration etc.)
• In Calendar software (day, week, month,  meeting, etc.)

Identifying User Objects#

User objects can be identified from

• discussion with users
• models and scenarios
• (optionally if one is available) a data model Identify objects from users by asking them!
• what objects do they perform the tasks on?
• what other objects are used in the task, i.e. what  objects are used as containers, tools, devices, inputs, reference sources?
• what additional objects would be useful if they  were available or feasible?

Characteristics of a User Object#

• contain other objects
  • useful when the user needs to manipulate collections of objects
  • e.g. in the calendar, Years contain Months contain  Weeks et. Days contain time slots.
• exist in a relationship with other objects
  • a relationship between objects may indicate that the related objects can be regarded as a single entity, at some level

• have attributes - describe characteristics of an object,
  • e.g., name, size, no. of objects in collection.
• have actions - the processes which can affect the object
  • e.g., delete, create, rename, sort
• have subtype - a subtype inherits the  attributes, actions etc. of its parent object type, but may well have additional attributes, actions etc. of its own.

User Object Modeling#

• To understand and define the user’s concepts of  the objects in the system
• To express required system behavior in terms of objects in the system, and actions that the  user can perform on them.

For more detail: Chapter 3-Interaction Design(Beyond human computer interaction)

User object model for a Calendar#

This includes (amongst other things):
Types of objects
   Days, weeks, months  Meetings, birthdays
Actions the user can perform on (or with) an object of a particular type (user object actions)
   Birthday – Add, remove, change
   Meeting – Add, remove, change
   (etc.)

Benefits of User Object Modeling#

• Promotes the usability of the GUI by ensuring that  serious thought is given to how the end-user will conceptualize and comprehend the objects in the system.
• Promotes an object-action style of user interface
• Promotes an object-based GUI design
• Helps the user to form a mental model of what is going on ->->->

We have learnt…#

✅What is a User Object?
✅Characteristics of User object?
✅User Object Modeling?
✅Benefits of User Object Modeling?

Mental (or Conceptual) Models#

To design for the Human Computer Interface we need to know how users approach a new interface:
When using a computer system, users have a mental model of what they hope to achieve: their goals and intentions
People don’t actually know everything about the interface but just work out what will be useful to them.
People try things out and look for patterns and consistencies - they are building a conceptual model of how the interface works

Errors#

Definition: Errors occur when there is a mismatch between the mental model a person has and the actual system or situation. These deviations lead to incorrect actions or decisions.
Example: Emma tries to close an application on her computer by clicking the red “X” button in the corner. However, the application doesn’t close because her mental model of the system is based on Mac OS, but she is using a Windows computer.

Slips vs. Mistakes#

Slip: you have the right mental model but  accidentally do the wrong thing
Example: James, who is familiar to his old car, turns the key in his new car’s ignition and realizes he has turned on the windshield wipers instead of the engine. His muscle memory is based on his old car’s setup.
Mistake: you have the wrong mental model
Example: Sarah mistakenly believes that all smartphones have the same operating system interface. When she tries to use gestures on her friend’s phone, it doesn’t work as expected because she applied the wrong mental model to a different system

• Improved design will reduce the chances of slips
• Improved affordance and feedback will reduce the chances of mistakes

Two Characteristics of Mental Models#

Help individuals understand and interact with systems

Structural models emphasize the system’s architecture (the “what”), while
Functional models focus on its behavior or operation (the “how”). Both models are crucial for understanding complex systems from different perspectives.

Uses of mental models#

The model will only help IF the users mental model is a true reflection of what is really the case!!

This is why we want interfaces to help construct good mental models.

Next week#

✅Paper Prototypes
✅Design Principles
✅Usability Testing