CS2003 Usability Engineering **updated**

What percentage of new product development fails due to a lack of understanding users' needs?

70% to 80%

What is the issue with software engineering methodologies?

They focus on providing system functionality over interactivity and the importance of the user.

What is the Waterfall Model?

A sequential development model with requirements written up front that does not involve users in the development process.

What is the Boehm's Spiral Model?

A software development model that allows for multiple rounds of development, testing, and evaluation but does not involve users.

What are the core values of Agile?

Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan

What is the Star Lifecycle?

A methodology for designing and evaluating interactive systems that emphasizes iteration and evaluation throughout the process and is applicable to both small and large projects.

What are the steps in the star lifecycle?

Situation, Task Analysis, Analysis, Revision, Implementation

Situation

Understand the context and goals of the user and the system being designed.

Task Analysis

Analyse the tasks that users need to perform with the system.

Analysis

In this stage, the usability of the system is evaluated, including user interface design, interaction design, and information architecture. This stage includes heuristic evaluations, cognitive walkthroughs, and usability testing.

Refinement

Develop detailed designs, prototypes, and usability tests to refine the system's design.

Testing

Test the system's usability with representative users and evaluate the results.

What is the Design Thinking Process?

A problem-solving methodology that emphasizes empathy, creativity, and iterative testing to create innovative and effective solutions.

empathise

This stage involves understanding the needs, wants and feeling of the people who are experiencing the problem.

define

Once problem has been identified the next stage is to define the problem more clearly

ideate

This stage involves generating wide range of potential solutions to the problem

prototyping in the design thinking process

Once potential solutions are generated, the next step is to create a prototype of the solution.

What is the Double Diamond?

A problem-solving methodology consisting of four stages that are grouped into two diamonds, representing the divergent and convergent thinking stages of the design process.

test

Involves testing prototype with users to gain feedback.

What are the steps in the Double Diamond

Stage 1 Discover Stage 2 Define Stage 3 Develop Stage 4 Deliver

Stage 1 Discover:

Involves identifying and understanding the problem through research analysis and observation
Goal is to explore problem space broadly

Stage 2 Define:

Involves developing the insights gained in stage 1 to create a clear problem statement
Goal is to define the problem narrowly and identify the key issues to be addressed.

Stage 3 Develop:

Involves generating potential solutions to the defined problem statement
Goal is to explore wide range of ideas and develop them into workable solutions

Stage 4 Deliver:

Involves prototyping and testing the potential solutions developed in the previous stage
Goal is to refine and improve the most promising solutions until final design is reached.

Visibility

The ability of users to see and understand the available options and actions in the user interface.

Feedback

The immediate response that users receive after taking an action in the user interface.

Constraints

Design elements that prevent users from making mistakes or performing unintended actions.

Mapping

The relationship between the controls and the results in the user interface.

Consistency

The use of the same design elements and interaction patterns throughout the user interface.

Affordance

The visual or physical cues in the user interface that suggest how an object should be used.

Aesthetics

The emotional appeal and attractiveness of the user interface.

Semantic networks

web of concepts linked through association
easy way to explore problem space
requires knowledge of problem space

what do we use prototyping for

work out details and test them, quickly and cheaply build features of interest, concrete approach, users can suggest changes

why do we need to quickly and cheaply build features of interest

to try them out

Describe Mental models as a form of knowledge representation

They are simplified versions of reality

Describe the Interactional utility of mental models

supports understanding of system operations

Structural

understanding the components and their relationships

Conceptual model

defines how systems are designed to be understood

A Good conceptual model is a high level description of

- the proposed system in terms of a set of ideas
- what it should do, behave and look like
- how it should be understood by users

Card Sort

organise info collected in a discovery phase
quick and easy
difficult to navigate

Flowcharts

identifies elements or computation processes

Scenario

give rich picture of user's tasks

What do Scenarios show?

- Basic goal
-Conditions
-Activities
-Outcomes

Conceptual design involves

structuring information space, creating of alternative solutions, determining which design concept to pursue.

Human-centred design process

specifies general activities to be performed in development, does not demand or recommend particular techniques or methods

Design process

involves searching for an acceptable design in a infinitely large design space

3 problems with prototyping

may not search for solution effectively, may not recognise a good design, may think a bad design is good.

when do we prototype

application area is poorly defined, cost of rejection is high, final version is essential to be right first time, requirement to assess impact of change.

Evolutionary Prototyping

final design looks similar initial design

horizontal prototyping

providing a lot of requirements but not functionality

why is wizard of oz prototyping useful?

allows for early designs to be tested.

what form of fidelity layout design is wireframing?

low fidelity

Mental Models

Models people have of themselves, others, their environments and things with which they interact

Mental models are formed by ...

Self, shown by others, told by someone else

Psychological utility of mental models

simple, help us make sense of the way the world works

Types of mental models

functional, structural

Functional

knowing what to do but not why

Ways to design

brainstorm, card sort, semantic networks, flowcharts, scenarios.

Brainstorm

team activity, combine and improve ideas

prototype

building a physical working model of all or parts of the system and using it to identify weaknesses in the understanding of the real requirements

best practices in prototyping

If you want to look at social and cognitive effects, use hands-on testing by users in realistic scenarios, use with a design/evaluation methodology integrating prototype testing.

concrete approach

show users what inputs, intermediate stages and outputs look like

Prototyping works out details and tests them

in ways not possible at level of verbal description

prototyping car design examples

doodles, blueprint, scale models, computer models

product conceptualisation

allows exploration of alternative designs

methods for prototyping

requirements animation, rapid prototyping, evolutionary prototyping, incremental prototyping

requirements animation

shows what the system would do but user cannot interact with it

Rapid Prototyping

collect information on requirements, at end of each prototype we discard the prototype, taking the good and leaving the bad.

Incremental Prototyping

building and refining a prototype in stages, with each stage adding additional features and functionality to the prototype

Economic principle of prototyping

the best prototype is one that in the simplest and most efficient way makes the possibilities and limitation of a design idea visible and measurable.

full prototype

full unpolished components with functionality

paper prototype

sketch on paper, has no functionality

vertical prototyping

providing a lot of functionality but for little requirements

low fidelity vs high fidelity prototypes

low fidelity are rough mock-ups, high fidelity are detailed more advanced prototypes that are closer to the final product.

Wizard of oz prototype

a human intermediary intercepts commands from the user and instructs the system to carry them out.

card-based prototyping

each card represents one screen, used in web development

wireframing

wireframes similar to blueprints, each wireframe represents an individual screen.

describe wireframing

contains main info, abstracted from content, visual description of UI.

problems with paper prototypes

concepts and terminology, navigation problems, content, help, requirements/functionality.