Flashcards in Unit 2: Goals and design principles Deck (23)
Usability vs User experience goals
Usability goals - meeting specific usability criteria.
User experience goals - nature of user experience (how they perceive product rather than from product perspective).
Distinction not clear cut - both linked to each other.
Usability goals. (6)
Effectiveness (effective to use).
Efficiency (efficient to use).
Safety (safe to use).
Utility (having good utility).
Learnabilty (easy to learn).
Memorability (easy to remember how to use).
Effectiveness (def and question)
General goal - how good is something at doing what it's supposed to.
Q: Is product capable of allowing people to learn, carry out their work efficiently, access info needed or buy goods wanted?
Efficiency (def and question)
How well a product supports users in carrying out tasks.
Q: Once products tasks learned, can users sustain a high level of productivity?
Safety (def and question)
How well a product protects users from dangerous conditions and undesirable situations.
Q: What is the range of possible errors and what measures are there to permit users to recover easily from them?
2 aspects of safety?
Hazardous working conditions, eg. X-ray, chemicals - need to interact remotely.
Avoiding unintended actions; also perceived fears of consequences of making errors and how this affects user behaviour.
How to make product safer in 2nd aspect of safety. (2)
Prevent serious errors by reducing risk of pressing wrong button (eg. place 'quit', 'delete', etc away from 'save').
Provide means of recovery from errors - confidence to explore and try new operations.
Eg. Undo and confirmatory dialog boxes ("Are you sure you want to delete?").
Utility (def and question)
The extent to which a product provides the right kind of functionality so users can do what they need or want.
Q: Does the product provide an appropriate set of functions that will enable users to carry out tasks in the way they want to?
Learnability (def and question)
How easy a product is to learn to use.
Q: Can a user work out how to use a product by exploring the interface and trying out actions?
How hard is it to learn all the functions in this way?
Memorability (def and question)
How easy a product is to remember how to use, once learned.
Q: What kinds of interface support have been provided to help users remember how to carry out tasks, especially for products and operations used infrequently?
Usability criteria (def and examples)
Specific objectives that enable the usability of a product to be assessed in terms of how it can improve (or not) a user's performance.
Time to complete a task (efficiency)
Time to learn a task (learnability)
Number of errors made when carrying out a given task over time (memorability)
User experience goals use.
Used to improve the way interaction with a product feels to the user.
User experience goals (10 examples)
Supportive of creativity.
Concept of flow?
State of intense emotional involvement that comes from being completely involved in an activity.
Eg. leading web visitor to unexpected place where they become absorbed.
Generalisable abstraction intended to orient designers towards thinking about different aspects of their design.
Don't specify how to actually design interface.
Design principles. (6)
Controls should be clearly visible, so users can see they're available.
Visual feedback should also be clearly visible so users can understand what action has been done and what affect has been achieved and hence what needs to be done next.
The information sent back to the user about what action has been done and what has been accomplished.
(Visual, auditory or tactile).
Ways of restricting the kind of interaction that can take place at a given moment.
Eg. menu options greyed out.
The interface follows rules, eg. always selecting objects with the left mouse button, 'help' menu always at RHS of menu bar.
Internal - UI consistent within itself.
External - UI consistent with outside world.
An attribute of an object that allows people to know how to use it. (May be perceived affordance).
A learned mapping between a screen representation of a control and its operation.