COMM1PCOMM1P Alan Woolrych Temporary Module Handbook now available at: cs0gco/COMM1P01_HBT.doc Usability Evaluation 3

COMM1P

Alan Woolrych

Temporary Module Handbook now available at:http://osiris.sunderland.ac.uk/~cs0gco/COMM1P01_HBT.

doc

Usability EvaluationUsability Evaluation

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• SCET MSc EC/ECA © Gilbert Cockton 2001

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The Rule of HCI: ReminderThe Rule of HCI: Reminder09:0309:03

• Good Design …

• … demonstrably fits …

• … its context of use

• This lecture explains what we mean for HCI by “demonstrably”


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3 Fundamentals: Reminder 3 Fundamentals: Reminder 09:0409:04

• Context

• Design

Evaluation


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How Evaluation Fits InHow Evaluation Fits In09:0509:05

Evaluation

Constrains

Informs

Tests

Fits

Implies

Context

Design

Implies


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Forms of EvaluationForms of Evaluation09:0609:06

• Formative• What’s wrong (and what’s good!)• Earlier rather than later

• Summative• How well it has (not) done• At the end of each significant design

iteration• Before going live• Before getting venture capital


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ContextContext of Use of Use09:0809:08

“of use” is a specialisation, a restriction to environments of usage, success and

failure

evaluations should (re-)create such contexts


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Cover the Context in Cover the Context in EvaluationEvaluation 09:1009:10

• Typical end-users and key stakeholders

• Use real tasks within real activities wherever possible• ensure realistic motivation

• Test in real usage settings where possible


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Approaches to EvaluationApproaches to Evaluation09120912

• Analytical• deduction, inference, constructing

arguments based on inspection of web-site

• Empirical• factual, evidence gathered from real

usage by real people


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Inspection MethodsInspection Methods 09130913

• Heuristic Evaluation• Keith Instone’s Web Interpretations

• Cognitive Walkthrough• Novice users, learning site for first time

• “Scent” analysis (semiotic engineering)• How strong are link “affordances”?• How suggestive (and accurate) is a link?


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Heuristic Evaluation 1Heuristic Evaluation 109170917

• Visibility of system status (Nielsen)• The system should always keep users informed about what is

going on, through appropriate feedback within reasonable time.

• Instone• Probably the two most important things that users need to

know at your site are "Where am I?" and "Where can I go next?"

• Make sure each page is branded and that you indicate which

section it belongs to. Links to other pages should be marked. Since users could be jumping to any part of your site from somewhere else, you need to include this status on every page.


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• Match between system and the real world• The system should speak the users' language, with words,

phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

• Instone• On the Web, you have to be aware that users will probably

be coming from diverse backgrounds, so figuring out their "language" can be a challenge.


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• User control and freedom• Users often choose system functions by mistake and need a

clearly marked "emergency exit" to leave unwanted states without having to go through an extended dialogue. Support undo and redo.

• Instone• Many “emergency exits” are provided by the browser, but

there are still things open to designers, especially taking away the user control that is built into the Web!

• “Home” button on every page, care with forcing users into certain fonts, colors, screen widths, browser versions, and "advanced technologies” e.g., animated GIFs. Until browsers let users stop and restart the animations, they can do more harm than good.


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• Consistency and standards • Users must not wonder whether different words, situations,

or actions mean the same thing. Follow platform conventions.

• Instone• Word content and buttons consistently. Check titles and

headers against links.

• Users jump onto (and off of) sites from others. Custom link colors may work well for one site but could conflict with the rest of the Web, and make a site hard to use.

• Follow HTML and other specifications. Deviations are opportunities for unusable features to creep into a site.


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• Error prevention• Even better than good error messages is a careful design

which prevents a problem from occurring in the first place.

• Instone• Limitations of HTML forms mean that inputting information

on the Web is a common source of errors. Until full-featured, GUI-style widgets arrive , use JavaScript to prevent errors before users submit, but still double-check after submission.


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• Recognition rather than recall• Make objects, actions, and options visible. The user should

not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

• Instone• If users can recognize where they are from the current page,

without recall of their path there, they are less likely to get lost.

• Server-side image maps are invisible. Client-side maps (need java/script) are better iff images make links salient.

• Good labels and descriptive links are also crucial for recognition.


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• Flexibility and efficiency of use• Accelerators - unseen by novices - may speed up interaction for

experts so that systems can cater to both inexperienced and experienced users. Let users tailor frequent actions.

• Instone• Bookmarks! Make site easy to bookmark, and corners of

interest too. Don’t let frames prevent users from bookmarking effectively.

• Avoid temporary URLs with a short lifespan. Make sure a URL lives on, even after content is taken down.

• GET instead of POST on forms. GET attaches parameters to URL, so users can bookmark the results of a search.

• Easy to link to lets others create specialised views of your site (e.g., Amazon.com's associates program)


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• Aesthetic and minimalist design• Dialogues should not contain information that is irrelevant

or rarely needed. Every extra unit of information in a dialogue competes with relevant units of information and diminishes relative visibility.

• Instone• Use progressive levels of detail. Let users drill down to

details. Provide a way to go "up" to get the bigger picture for when users jump into the middle of a site. Get to rarely needed information via links.

• Write content for the Web. Break information into chunks and link to relevant chunks to support different uses of content.


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• Help users recognise, diagnose, and recover from errors• Express error messages in plain language (no codes),

precisely indicate the problem, and constructively suggest a solution.

• Instone• Errors will happen, despite all efforts to prevent them.

Every error message should offer a (link to a) solution on the error page. If a search yields no hits, do not advise broadening a search. Provide him a link that will broaden the search.


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•Heuristic Evaluation 10Heuristic Evaluation 1009400940

• Help and documentation• Even though systems are best used without documentation, it may

be necessary to provide help. This should not be too large, be easy to search, focused on user tasks, listing concrete steps to be carried out.

• Instone• Some basic sites need little documentation, if any. But

complicated tasks need help.

• Don’t just slap up help pages, integrate documentation into sites.

• Link from your main sections into specific help and vice versa. Help could even be fully integrated into each page so users never feel assistance is too far away.


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BreakBreak 09400940

• Back at 09:55 Prompt!


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Planning InspectionsPlanning Inspections09550955

• Analyst training• Method

• Site and Context (especially usage activities)

• Problem Reporting• Fixed Format: Summary, Context,

Assumed Cause(s), Likely Difficulties

• Improves Predictions, Supports Merging


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Report FormatReport Format10001000

Problem #

Brief Description

A description of the problem identified.

Likely Difficulties

A description of the likely difficulties the particular problem will

cause the user.

Specific Context (if applicable)

A description of the context in which the potential problem

would occur. For example, a particular problem may only

occur in a specific context, such as the start up of the

application, and not at any other timer during normal use of the

application.

Assumed Causes

Judgements as to the cause of the problem.

Relevant Guideline/Heuristic/Walkthrough Step

The guideline etc. conformed to or breached


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Model-Based MethodsModel-Based Methods10031003

• GOMS• Goals, Operators, Methods, Selectors• Expert Error Free Use

• Keystroke Level Model/CP-GOMS• Time estimates

• Cognitive Modelling (examples)• Gaze Prediction• How suggestive (and accurate) is a link?


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Empirical MethodsEmpirical Methods10051005

• Paper prototype testing• Lab Testing• Field Testing• Remote observation and

instrumentation• Site Feedback


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Planning TestsPlanning Tests10081008

• Who?• Typical Users, Key Stakeholders• Evaluator present or remote, real-time or

retrospective

• What - (de)briefing, appropriate activities?

• Where - Lab or field?

• Instruments - recording, notes, logs (careful!)


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Paper Prototype Paper Prototype 10111011

• Fidelity Investment’s Rapid Testing• Print outs of page designs• Typical users asked

• 'Where do you look?'

• "Where would you find?"

• 'Where would you click?'

• 'What do you remember/did you learn?'

• Can you guess what this is?" (false text)


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Lab. TestingLab. Testing 10131013

• Pros• Controlled, recorded• Can focus on areas of concern (from

inspections)

• Cons• Out of Context• Unrealistic, user’s motivation may be

unnatural, learning effects with fixed tasks


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Our LabOur Lab


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Our LabOur Lab


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Field TestingField Testing 10161016

• Pros• In context• Realistic, natural motivation within real

work settting and users’ own tasks

• Cons• Difficult to control and record• Much information gets missed/lost• May get no data on areas of concern


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Remote Observation and Remote Observation and InstrumentationInstrumentation 10181018

• Pros• As field testing plus• Cheap to cover many users and contexts

• Cons• Significant loss of data (Activity Theory,

recall binoculars example)• Can be intrusive


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Site FeedbackSite Feedback10201020

• Pros• As remote observation

• Cons• Unreliable• Tendency to vent by loud mouths• Performance does not correlate to

preference


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Content 1: ReminderContent 1: Reminder10211021

• Human-Computer Interaction for the Web• Context Research

Usability Evaluation,

• Information Architecture

• Conceptual Functionality

• Navigation Structures, Display Design, Interaction Techniques


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Web-PageWeb-Page 10231023

• http://osiris.sunderland.ac.uk/~cs0gco/comm1p.htm

• Module Handbook (Temporary)

• First Assignment

• Slides & Exercise

• Resources & Links


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SummarySummary 10251025

• Plan Evaluations• Formative - when, where, how

• Summative - what, who, why

• Use Evaluations• If the design is broken, fix it

Documents

COMM1PCOMM1P Alan Woolrych Temporary Module Handbook now available at: cs0gco/COMM1P01_HBT.doc Usability Evaluation 3