ReseaRch MethoD 94UsabilityTesting Usability testing focuses on people and their tasks, and seeks empirical evidence about how to improve the usability of an interface. 1 Usabilitytestingisanevaluativemethodthatallowsteamstoobserveanindividual'sexperience withadigitalapplicationasheorshewalksthroughthestepsofagiventask(orsetoftasks).The methodisdesignedtohelpteamsidentifythepartsofaninterfacethatmostregularlyfrustrateand confusepeoplesothattheycanbeprioritized,fixed,andretestedpriortolaunch. Testsaredesignedaroundtasksandscenariosthatrepresenttypicalend-usergoals.Itiscommon practicethateveryoneontheinterdisciplinaryteamworkstogethertoidentifyusabilitytestingtasks andscenarios.Tasksshouldbespecific,concrete,andreflectactualgoalsofthetargetaudience. Scenarioscontextualizethetask,andarewrittentoprovideextrainformationnecessarytocom- pletethetask.Tasksandscenariosshouldneitherinfluencetheparticipanttosolveaproblemacer- tainway,norseektojustifyproductrequirements(whichoftenreflectsystemordevelopergoals). UsabilityteststypicallyfollowtheformatoftheThink-aloudProtocoltechnique.Someoftheerrors thatobserversandevaluatorsshouldtrytodetectincludeanyinstancewheretheparticipant: 2 1. understandsthetaskbutcan'tcompleteitwithinareasonableamountoftime; 2. understandsthegoal,buthastotrydifferentapproachestocompletethetask; 3. givesuporresignsfromtheprocess; 1.Gould,JohnD.,andClaytonLewis. "DesigningforUsability:KeyPrinciplesand WhatDesignersThink."Communications of the ACM28,no.3(1985):300-311. 2.Jacobsen,NielsEbbe,andBonnieE.John. "TheEvaluatorEffectinUsabilityStudies: ProblemDetectionandSeverityJudgments." Proceeding of the Human Factors and Ergonomics Society 42nd Annual Meeting, 1998. 3.Mack,Robert,ClaytonH.Lewis,andJohn M.Carroll."LearningtoUseWordProcessors: ProblemsandProspects."ACM Transactions on Information Systems1,no.3(1983): 254-271. 4.Virzi,RobertA."RefiningtheTestPhase ofUsabilityEvaluation:HowManySubjects isEnough?"Human Factors34,no.4(1992):