Observing Users (Introducing C3: User Focus and Perspective)1 Jacques Terken ID: Unit Communication Research group UCE (User-Centered Engineering)

Observing Users (Introducing C3: User Focus and Perspective)2 Agressie opgewekt door interactie met systemen

Observing Users (Introducing C3: User Focus and Perspective)3 Belang van User Focus volgens bedrijven

Observing Users (Introducing C3: User Focus and Perspective)4 Relationship between Effort and Costs Fixing an error in the early product development phase costs about 2-10 $ Fixing an error in the late product development phase costs about $ Conclusion: the more effort at the beginning, the less cost at the end! (ref.: Barry Boehm, Software Engineering Economics. 1981, Englewood Cliffs, ISBN X)

Observing Users (Introducing C3: User Focus and Perspective)5 Opdracht: Ontwerpen van gebruiksvriendelijke interfaces voor interactieve systemen/producten/diensten HCI  Ergonomie Discussie: –De intuitieve interface Case: mobiele telefoon

Observing Users (Introducing C3: User Focus and Perspective)6 Bronnen Voorafgaande kennis (Literatuur/Richtlijnen/Standaards/Eigen ervaring etc) Informatie van en over gebruikers verkregen door middel van gebruikerstest, interviews etc

Observing Users (Introducing C3: User Focus and Perspective)7 User research

Observing Users (Introducing C3: User Focus and Perspective)8 Utility vs Usability Schackel (1991): Onderscheid Utility – Usability – Likeability utility--will the system/product do what is needed functionally? usability--will the users actually work it successfully? likeability--will the users feel it is suitable?

Observing Users (Introducing C3: User Focus and Perspective)9 Requirements Functionele requirements: “Wat moet het systeem doen” (omvat Constraints) methoden: observatie, analyse van documenten, interviews, … resultaat bijv. In de vorm van dataflow diagram

Observing Users (Introducing C3: User Focus and Perspective)10 Niet-functionele/ usability requirements (Schackel): –Throughput/Effectiveness: Performance in accomplishment of tasks--the access to potential utility (Usability metrics: tasks accomplished, speed of task execution, errors made ) –Learnability: Degree of learning to accomplish tasks--the effort required to access utility –Flexibility: Adaptation to variation in tasks--the range of tasks for which there is utility –Attitude: User satisfaction with system--the manifestation of potential likeability

Observing Users (Introducing C3: User Focus and Perspective)11 Usability ISO /DIS 9241: –Usability: The effectiveness, efficiency, and satisfaction with which specified users achieve specified goals in particular environments. –Effectiveness: The accuracy and completeness with which specified users can achieve specified goals in particular environments. –Efficiency: The resources expended in relation to the accuracy and completeness of goals achieved. –Satisfaction: The comfort and acceptability of the work system to its users and other people affected by its use.

Observing Users (Introducing C3: User Focus and Perspective)12 Ontwerpsituaties Interface voor bestaand systeem verbeteren Interface ontwikkelen als onderdeel van ontwikkeling van nieuw systeem Doel in beide situaties: ontwerpen van gebruiksvriendelijke interface

Observing Users (Introducing C3: User Focus and Perspective)13 Ontwerpcyclus Definitie Requirements (“eigenaar”?) Specificaties (high level/low level) Implementatie Evaluatie [ Release (Sales, After sales) ] Sleutelwoord: iteratief

Observing Users (Introducing C3: User Focus and Perspective)14 Mental models and Everyday reasoning You arrive home on a cold winter’s night to a cold house. How do you get the house to warm up as quickly as possible? Set the thermostat to be at its highest or to the desired temperature?

Observing Users (Introducing C3: User Focus and Perspective)15 Heating up a room that is thermostat-controlled Many people have erroneous mental models (Kempton, 1996) –General valve theory, where ‘more is more’ principle is generalised to different settings (e.g. gas pedal, gas cooker, tap, radio volume) –Thermostats based on model of on-off switch model

Observing Users (Introducing C3: User Focus and Perspective)16 Heating up a room that is thermostat-controlled Same is often true for understanding how interactive devices and computers work: –Poor, often incomplete, easily confusable, based on inappropriate analogies and superstition (Norman, 1983) –e.g. frozen cursor/screen - most people will bash all manner of keys

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Observing Users (Introducing C3: User Focus and Perspective)18 Kennisniveaus Rasmussen (1986): Skills Geautomatiseerde, sterk geintegreerde gedragspatronen die plaats vinden zonder bewuste controle Rules de gebruiker beschikt over stelsel van regels of procedures op basis van eerdere confrontaties, uit een instructie, of via iemand anders General knowledge in onbekende situaties, waar de gebruiker geen kennis of regels beschikbaar heeft op basis van eerdere confrontaties, stelt hij/zij en plan op (of meerdere alternatieve plannen), en probeert de utkomst te voorspellen op basis van een analyse van de eigenschappen van de situatie (“model-gebaseerd”)

Observing Users (Introducing C3: User Focus and Perspective)19 Mentaal model Mentaal model: verzameling regels over hoe het systeem bediend moet worden Knowledge-based approach: Gebruiker genereert hypothesen over hoe het systeem bediend moet worden op basis van algemene kennis en de manier waarop het systeem zich presenteert Hypothese testen: positief resultaat leidt tot regel

Observing Users (Introducing C3: User Focus and Perspective)20 Visibility

Observing Users (Introducing C3: User Focus and Perspective)21 Resident pathogens Latent error opportunities embedded in system complexity, procedures, training inadequacies etc. Include design errors due to wrong affordance and mapping

Observing Users (Introducing C3: User Focus and Perspective)22 Affordance (Norman) Refers to the perceived and actual properties of a thing Primarily those fundamental properties that determine just how the thing –Could possibly be used –Cannot be possibly used

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Observing Users (Introducing C3: User Focus and Perspective)26 Opdracht Lees voorwoord en hoofdstuk 1 van Norman (introduceert en illustreert begrippen zoals visibility, mapping en affordance) Formeer groepjes van 3 a 4 personen en bestudeer in de omgeving hoe mensen met artefacten omgaan. Let daarbij speciaal op de affordance van de artefacten Beschrijf de activiteiten en de observaties in een kort verslag

Observing Users (Introducing C3: User Focus and Perspective)27 Verdere informatie: (Further reading, met verwijzingen naar nuttige/vermakelijke websites)