Föreläsning

Comments

Transcription

Föreläsning
Entertainment Services
Usability- användbarhet
Tekniker, metoder och annat vi måste
känna till för att kunna använda oss
av usability som ett framgångsrecept
i design av IT & digitala medier.
Charlotte Wiberg
[email protected]
Charlotte Wiberg
Entertainment Services
Veckans agenda
• 
• 
• 
• 
• 
• 
Usability vad är det?
Definitioner på användbarhet.
Utvärdering i stort inom HCI & ID - vad har vi för andra
möjligheter?
Utvärderingsmetoder – två huvudspår
–  Empiriska utvärderingsmetoder
–  Expertmetoder
Metodologiska avvägningar
Utvärdering i relation till designprocessen
Charlotte Wiberg
Entertainment Services
Människa-Datorinteraktion - ett
forskningsfält mellan teori och praktik.
Understanding
Informing
Human Beings
Artifact
Worker
Tool
User
UI
Evaluation
Designing
Charlotte Wiberg
Entertainment Services
Vanliga frågor
• Hur ser en professionell målgruppsanalys/användartest ut?
• Hur gör man en sån test?
-personliga intervjuer?
-kvalitets test?
-kvantitetstest?
• Vilka fel kan man göra?
• Hur använder man sig av resultatet?
• Hur presenterar man sitt resultat?
• När bör man göra en sån här test?
• När bör man inte göra
en sån här test?
Charlotte Wiberg
Entertainment Services
Usability
Charlotte Wiberg
Entertainment Services
The context
of usability
(Nielsen, 1993)
System Acceptability
Practical acceptability
Social acceptability
Cost
Reliability
Compatibility
Etc.
Usefulness
Utility
Charlotte Wiberg
USABILITY
Learnability
Efficiency
Memorability
Errors
Satisfaction
Entertainment Services
Usability aspects
(Nielsen, 1993)
• 
Learnability:
• 
• 
The system should be easy to learn so that the user can rapidly
start getting some work done with the system.
• 
Efficiency:
• 
• 
The system should be efficient to use, so that once the user has
learned the system, a high level of productivity is possible.
• 
Memorability:
• 
• 
• 
The system should be easy to remember, so that the casual user
is able to return to the system after some period of not having used it,
without having to learn everything all over again.
• 
Errors:
• 
• 
• 
The system should have a low error rate, so that users make few errors
during the use of the system, and so that if they do make errors they can
easily recover from them. Further, catastrophic errors must not occur.
• 
Satisfaction:
• 
• 
The system should be pleasant to use so that users are subjectively satisfied
when using it; they like it.
Charlotte Wiberg
Entertainment Services
Vad utvärdera?
• 
• 
• 
Uppgift - task
Aktivitet - activity
Process - process
• 
Task analysis kopplas ofta till usability
Charlotte Wiberg
Entertainment Services
Utvärderingsmetoder för användbarhet
•  Dels grovt upp i:
–  Empiriska utvärderingsmetoder
–  Expertutvärderingsmetoder- inspektionsmetoder
Charlotte Wiberg
Empiriska metoder Entertainment Services
Method
Measures
Generated data
Think-aloud (or verbal) protocol
Captured events from usage
situations; problems,
expectations etc.
Use data collection
Clinical experiments
Surveys and Questionnaires
Interviews
Number of errors, types of
errors, time to complete task
Record of cognitive processes
of users in system usage
Record of statistics for errors,
listings of types of occurring
errors, time statistics
Eye gaze, heart rate, skin
color, body heat
Statistics for measured clinical
aspects
Accuracy regarding memory,
learning etc.
Record of answers –
quantitative or qualitative
General information from
users. Structured or
unstructured.
Charlotte Wiberg
Record of answers - qualitative
Entertainment Services
Usabilitylabb
Charlotte Wiberg
Entertainment Services
Usabilitylabb (forts)
Charlotte Wiberg
Expertutvärderingsmetoder
(1)
Entertainment
Services
Method
Characteristics of
evaluators
Number of
evaluators
Heuristic evaluation
Usability experts
One
Goals of inspection
Judge whether each
element in interface
follows heuristics
Cognitive
Walkthrough
Cognitive
Psychologists
Formal usability
inspections
One
One or
group
Design
(or pluralistic)
Walkthroughs
Users, developers
and Human Factor
HCI experts
One or
group
Charlotte Wiberg
Predictions of user
behavior regarding
learning
Combines Heuristic
Ev. with Cog.
Walkthrough
Walkthrough of each
dialogue element by
using scenarios
Expertutvärderingsmetoder
(2)
Entertainment
Services
Method
Characteristics of
evaluators
Number of
evaluators
Feature inspection
Goals of inspection
Inspection of
sequences of
(complicated)
features
Consistency
inspection
(External)
designers
Standard
inspections
Expert in (specific)
standard(s)
Theory-based
reviews
Experts in each
method
Charlotte Wiberg
Group
Comparison of
different designs to
check consistency
One
Inspection of interface
for compliance with
standard(s)
One
Discover problems on
a micro-level.
Heuristic EvaluationEntertainment
(Nielsen, J) Services
1.  Visability of system status
The system should always keep users informed about what is going on, through
appropriate feedback within reasonable time. 2.  Match between system and 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. 3.  User control and freedom
Users often choose system functions by mistake and will need a clearly marked
"emergency exit" to leave the unwanted state without having to go through an
extended dialogue. Support undo and redo. 4.  Consistency and standards
Users should not have to wonder whether different words, situations, or actions
mean the same thing. Follow platform conventions. 5.  Error prevention
Even better than good error messages is a careful design, which prevents a
problem from occurring in the first place. Charlotte Wiberg
Entertainment Services
Heuristic Evaluation (2)
6.
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.
7. Flexibility and efficiency of use
Accelerators -- unseen by the novice user -- may often speed up the
interaction for the expert user such that the system can cater to both
inexperienced and experienced users. Allow users to tailor frequent actions.
8. Aesthetic and minimalist design
Dialogues should not contain information which is irrelevant or rarely needed.
Every extra unit of information in a dialogue competes with the relevant units of
information and diminishes their relative visibility.
9. Help users recognize, diagnose and recover from errors.
Error messages should be expressed in plain language (no codes), precisely
indicate the problem, and constructively suggest a solution.
10.Help and documentation
Even though it is better if the system can be used without documentation, it
may be necessary to provide help and documentation. Any such information
should be easy to search, focused on the user's task, list concrete steps to be
carried out, and not be too large.
Charlotte Wiberg
Entertainment Services
Metodologiska avvägningar
• 
• 
• 
• 
• 
• 
• 
Design - implementation, var i process
Laboratorium - fältstudier
Subjektiv - objektiv, grad av tolkning
Kvalitativ - kvantitativ mätning
Tidpunkt för svar
Grad av involvering (intervention)
Resurser för utvärdering (labb,speglar.. )
Charlotte Wiberg
Entertainment Services
Från usability till user experience (UX)
• 
• 
• 
• 
• 
• 
• 
• 
2004 – en klar skillnad på traditionell användbarhet och UX
Idag vill vissa säga att det är samma sak för att vinna mark
–  ”allt är usability!”
–  ”allt är UX”
Samma problem kvarstår dock – oberoende vad vi kallar
aspekten så har vi en flora av metoder och mått som passar mer
eller mindre bra.
Viktigt att ha koll på Jordans trappa (User Needs)
Viktigt att skilja på typer av fel i relation till denna
Viktigt att kunna skilja svåra (severe) fel från mindre svåra fel
Detta avgörs från syftet med artefakten MEN om den är oklar blir
er uppgift att säga något om usability och/eller UX oklar!
Viktigt att informera/lära kunden om detta!
Charlotte Wiberg
Entertainment Services
Övningsuppgift:
• 
• 
• 
• 
Jobba tillsammans
2 informationsåtkomstwebbplatser
Skriv ner identifierade usabilityproblem
Hittar ni andra än sådant som inryms inom
heuristikerna?
•  45 minuter (max)
•  Redovisa för lärare samt diskussion (15
min)
Entertainment Services
Charlotte Wiberg
Entertainment Services
Utvärdering i designprocessen
Entertainment Services
Hur ser en designprocess ut?
Föranalys Analys Design
Progr. Utv/Dok
Var kan eller vill vi
utvärdera
användbarheten då?
Charlotte Wiberg
Entertainment Services
Designprocessen
Användar-
testets
lämplighet
Kostnad för
ändring av hittat fel
Prototypens
körbarhet
Expertmetodens
lämplighet
Tid
Wiberg
Föranalys AnalysCharlotte
Design
Progr. Utv/Dok
Entertainment Services
Iterativ design
•  Cykliskt tänkande där utvärdering återfinns
i varje fas.
•  Olika typer av utvärderingar används –
usability, utility, debugging mm
•  Iterationerna kan vara av olika längd
•  Kan vara kostsamt – i alla fall på kort sikt
•  Återfinns (tyvärr) mest inom
forskningsvärlden
Charlotte Wiberg