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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