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ISDE Revision Topics 2012

ISDE Revision Topics 2012

Compiled by Sheila Cassidy-Allan using J Burns slides

Exam Details

Date – Thursday 24 MayTime – 9amDuration 2hrs

Suggested time to read scenario and questions 30 minutes

Answer 2 of the 3 questions available

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ISDE Review

Goals of HCISafetyEffectivenessEfficiencyUsabilityAppealJustify Trade offs

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User Centred Activities

User AnalysisPrototypingUsability SpecificationsEvaluationTask Analysis

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User Characteristics

Physical DifferencesGeneral Differences

IntelligenceMotivationKnowledgeEducation

Cultural Differences

ISDE 2009

User characteristics: physical differences

Age (use larger fonts for older people)

Vision limitations, such as colour blindnessOther physical limitations that might restrict

movementSmall children don’t have good fine-muscle

control: see big buttons on next slide

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Frequent Uses/Infrequent User?

How can we design our interface to suit both types of users?

ISDE 2009

System Related User Characteristics

What characteristics can you expect of the users of your interface?frequency of usediscretion to use the systemknowledge of the task which the system will supportknowledge of computersexperience of other similar systemsgeneral abilities, e.g. literacy, visionattitude towards computers (and your system)existing skills (keyboard, mouse)

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Task Analysis

How is it used?How does it inform our design?

Task sequence – in what orderTask Frequency – how oftenTask Criticality – how importantTask Allocation – who or how

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Design Guidelines (Heuristic) use simple and natural dialogue sequencesspeak the users languageminimise user memory loadbe consistentprovide feedbackprovide clearly marked exitsprovide shortcutsprovide good error messagesprevent errors

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Ambiguous Design

What is this?Give an example

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Discretionary User?

What is this?Give an example

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UCD Activities

PrototypingWhat are the key techniques?

Horizontal /Vertical High & Low Fidelity prototypes examples?ThrowawayEvolutionaryIncremental and requirement gathering

+ and – of each

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What is a prototype?

In interaction design it can be (among other things):a series of screen sketchesa storyboard, i.e. a cartoon-like series of scenes a Powerpoint slide showa video simulating the use of a systema lump of wood (e.g. PalmPilot)a cardboard mock-upa piece of software with limited functionality written in the target language or in another language

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General Features of Prototyping

Enables the designer to quickly build or create examples of :-

The data entry formThe menu structure and orderThe dialogue stylesError messages

Should be inexpensive to develop – intention is to discard/modify it

Should not require programming skills

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What to prototype?

•Work flow, task design

•Screen layouts and information display

•Difficult, controversial, critical areas

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Low-fidelity Prototyping

•Uses a medium which is unlike the final medium, e.g. paper, cardboard

•Is quick, cheap and easily changed

•Examples:sketches of screens, task sequences, etc‘Post-it’ notesstoryboards‘Wizard-of-Oz’

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Paper Based Prototyping

Paper based prototypes These have no functionality but can still be useful

for:- Generating ideas Gaining insights into what the user might want or is thinking

Eg a paper based design of a data entry screen

Storyboards and Snapshotsusing “film-scripting” techniques to visualise

interactions between users and the systemThis is very quick and cheap

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Storyboards

•Often used with scenarios, bringing more detail, and a chance to role play

•It is a series of sketches showing how a user might progress through a task using the device

•Used early in design for example check availability or book What are the stages?

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High-fidelity prototyping

•Uses materials that you would expect to be in

the final product.

•Prototype looks more like the final system than a

low-fidelity version.

•For a high-fidelity software prototype common

environments include Macromedia Director, Visual

Basic, and Smalltalk.

•Danger that users think they have a full

system…….see compromises

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Aims of Prototyping in Software

The aim of prototyping is to resolve uncertainty about

functional and user requirementsoperation sequencesuser support needsrequired representations“Look and Feel” of the interfaceappropriateness of the design

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Software Prototyping

A software prototype will be a version of the proposed system with limited functionality

Will differ from the final system in terms ofSize, reliability robustness & completeness

A software prototype is “executable”can be thrown away, or evolvemay serve many different purposesshould be “quick and dirty” (and cheap!) is an integral part of user-centred design approaches

based on evaluation/modification

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Collecting Users Opinions

Questionnaires“open” (free form reply) or “closed” (answers “yes/no”

or from a wider range of possible answers)latter is better for quantitative analysis

important to use clear, comprehensive and unambiguous terminology, quantified where possiblee.g., daily?, weekly?, monthly? Rather than “seldom”,

“often” and there should always be a “never”Needs to allow for “negative” feedbackAll Form Fill-in guidelines apply!

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Components of a usability specification

Statement of the usability goalStatement of the usability attributeusability attributeStatement of the criteriacriteria which will represent

attainment of the specification Now level Worst case Planned level Best case

Statement of which set or subset of usersusers the specification applies to

A statement of preconditionspreconditions for the measurement

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Sample specification

Usability Goal: Users can quickly obtain a balance from an ATMAttribute: TimeMeasuring method: Observe and record Time

taken by users to obtain balance Now level: 30 secsWorst case: 25 secsPlanned level: 20 secsBest case: 15User class: AllPreconditions: Users are familiar with ATMs

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Usability Engineering

What is UE?You should now be able to write a

specification!What are the components of a usability

Specification?

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Interaction Elements

IconsSound/ Music speechVideo/PicturesTextColourWhat are some of the key design issues

surrounding each of these?

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The Primary Styles of Interaction

Q & AMenu selectionForm fill-inCommand languageDirect manipulationNatural language/Anthropomorphic

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Advantages and Disadvantages of MenusAdvantages

shortens learning curve reduces keystrokes structures decision-making permits use of dialogue-management tools allows easy support of error-handling

Disadvantages imposes danger of deep-nested menu hierarchies may slow frequent users consumes screen “real estate” requires rapid display rate

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Advantages and Disadvantages of Form Fill-inAdvantages

simplifies data entry requires modest training makes assistance convenient permits use of form-management tools

Disadvantages consumes screen “real estate”

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Q & A

Simple interaction styleUsers respond to series of questionsInput is usually Y/N or a particular single

inputPrint whole document?No of pages to print?No of copies

Evaluation J T Burns Feb 2010

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Reasons for Evaluation

UnderstandingUnderstanding the real worldparticularly important during requirements

gatheringComparingComparing designs

rarely are there options without alternativesvaluable throughout the development process

EngineeringEngineering towards a targetoften expressed in the form of a metric

Checking conformanceChecking conformance to a standard

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Evaluation Techniques

How applied? – how long, amount of errors (usability spec)

Techniques for doing evaluationsQuestion design

appropriate questionsJustification

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Observation and Monitoring - Direct Observation Protocol

Usually informal in field study, more formal in controlled laboratories

data collection by direct observation and note-takingusers in “natural” surroundingsquickly highlights difficultiesGood for tasks that are safety critical“objectivity” may be compromised by point of view

of observerusers may behave differently while being watched

(Hawthorne Effect)

Evaluation J T Burns Feb 2010

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Heuristic EvaluationUseful where method of operation is not fully

predictable and where user might not be a complete novice

Relies on a ‘team’ of evaluators to evaluate the designEach individually critiques the design –4/5

evaluators discover 75% of problemsSet of Design Heuristics (general guidelines) is

used to guide the evaluators – Prevent errors

Important Lectures to revise

Process of Interaction –wk 4Prototyping – wk 7-8Usability Engineering – wk 8Evaluation – wk 14&15

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